< draft-ietf-anima-autonomic-control-plane.txt   draft-ietf-anima-autonomic-control-plane.txt >
ANIMA WG T. Eckert, Ed. ANIMA WG T. Eckert, Ed.
Internet-Draft Futurewei USA Internet-Draft Futurewei USA
Intended status: Standards Track M. Behringer, Ed. Intended status: Standards Track M. Behringer, Ed.
Expires: 7 March 2021 Expires: 14 March 2021
S. Bjarnason S. Bjarnason
Arbor Networks Arbor Networks
3 September 2020 10 September 2020
An Autonomic Control Plane (ACP) An Autonomic Control Plane (ACP)
draft-ietf-anima-autonomic-control-plane-29 draft-ietf-anima-autonomic-control-plane-29
Abstract Abstract
Autonomic functions need a control plane to communicate, which Autonomic functions need a control plane to communicate, which
depends on some addressing and routing. This Autonomic Control Plane depends on some addressing and routing. This Autonomic Control Plane
should ideally be self-managing, and as independent as possible of should ideally be self-managing, and as independent as possible of
configuration. This document defines such a plane and calls it the configuration. This document defines such a plane and calls it the
skipping to change at page 1, line 43 skipping to change at page 1, line 43
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Table of Contents Table of Contents
1. Introduction (Informative) . . . . . . . . . . . . . . . . . 6 1. Introduction (Informative) . . . . . . . . . . . . . . . . . 6
1.1. Applicability and Scope . . . . . . . . . . . . . . . . . 9 1.1. Applicability and Scope . . . . . . . . . . . . . . . . . 9
2. Acronyms and Terminology (Informative) . . . . . . . . . . . 10 2. Acronyms and Terminology (Informative) . . . . . . . . . . . 10
3. Use Cases for an Autonomic Control Plane (Informative) . . . 16 3. Use Cases for an Autonomic Control Plane (Informative) . . . 16
3.1. An Infrastructure for Autonomic Functions . . . . . . . . 16 3.1. An Infrastructure for Autonomic Functions . . . . . . . . 16
3.2. Secure Bootstrap over a not configured Network . . . . . 17 3.2. Secure Bootstrap over a not configured Network . . . . . 16
3.3. Data-Plane Independent Permanent Reachability . . . . . . 17 3.3. Data-Plane Independent Permanent Reachability . . . . . . 17
4. Requirements (Informative) . . . . . . . . . . . . . . . . . 19 4. Requirements (Informative) . . . . . . . . . . . . . . . . . 18
5. Overview (Informative) . . . . . . . . . . . . . . . . . . . 20 5. Overview (Informative) . . . . . . . . . . . . . . . . . . . 19
6. Self-Creation of an Autonomic Control Plane (ACP) 6. Self-Creation of an Autonomic Control Plane (ACP)
(Normative) . . . . . . . . . . . . . . . . . . . . . . . 21 (Normative) . . . . . . . . . . . . . . . . . . . . . . . 21
6.1. ACP Domain, Certificate and Network . . . . . . . . . . . 22 6.1. Requirements for use of Transport Layer Security (TLS) . 21
6.1.1. ACP Certificates . . . . . . . . . . . . . . . . . . 23 6.2. ACP Domain, Certificate and Network . . . . . . . . . . . 22
6.1.2. ACP Certificate AcpNodeName . . . . . . . . . . . . . 25 6.2.1. ACP Certificates . . . . . . . . . . . . . . . . . . 23
6.1.2.1. AcpNodeName ASN.1 Module . . . . . . . . . . . . 28 6.2.2. ACP Certificate AcpNodeName . . . . . . . . . . . . . 25
6.1.3. ACP domain membership check . . . . . . . . . . . . . 29 6.2.2.1. AcpNodeName ASN.1 Module . . . . . . . . . . . . 28
6.1.3.1. Realtime clock and Time Validation . . . . . . . 31 6.2.3. ACP domain membership check . . . . . . . . . . . . . 29
6.1.4. Trust Anchors (TA) . . . . . . . . . . . . . . . . . 32 6.2.3.1. Realtime clock and Time Validation . . . . . . . 31
6.1.5. Certificate and Trust Anchor Maintenance . . . . . . 33 6.2.4. Trust Anchors (TA) . . . . . . . . . . . . . . . . . 32
6.1.5.1. GRASP objective for EST server . . . . . . . . . 34 6.2.5. Certificate and Trust Anchor Maintenance . . . . . . 33
6.1.5.2. Renewal . . . . . . . . . . . . . . . . . . . . . 36 6.2.5.1. GRASP objective for EST server . . . . . . . . . 34
6.1.5.3. Certificate Revocation Lists (CRLs) . . . . . . . 36 6.2.5.2. Renewal . . . . . . . . . . . . . . . . . . . . . 36
6.1.5.4. Lifetimes . . . . . . . . . . . . . . . . . . . . 37 6.2.5.3. Certificate Revocation Lists (CRLs) . . . . . . . 36
6.1.5.5. Re-enrollment . . . . . . . . . . . . . . . . . . 37 6.2.5.4. Lifetimes . . . . . . . . . . . . . . . . . . . . 37
6.1.5.6. Failing Certificates . . . . . . . . . . . . . . 39 6.2.5.5. Re-enrollment . . . . . . . . . . . . . . . . . . 37
6.2. ACP Adjacency Table . . . . . . . . . . . . . . . . . . . 39 6.2.5.6. Failing Certificates . . . . . . . . . . . . . . 39
6.3. Neighbor Discovery with DULL GRASP . . . . . . . . . . . 40 6.3. ACP Adjacency Table . . . . . . . . . . . . . . . . . . . 39
6.4. Candidate ACP Neighbor Selection . . . . . . . . . . . . 44 6.4. Neighbor Discovery with DULL GRASP . . . . . . . . . . . 40
6.5. Channel Selection . . . . . . . . . . . . . . . . . . . . 44 6.5. Candidate ACP Neighbor Selection . . . . . . . . . . . . 43
6.6. Candidate ACP Neighbor verification . . . . . . . . . . . 47 6.6. Channel Selection . . . . . . . . . . . . . . . . . . . . 44
6.7. Security Association (Secure Channel) protocols . . . . . 47 6.7. Candidate ACP Neighbor verification . . . . . . . . . . . 48
6.7.1. General considerations . . . . . . . . . . . . . . . 48 6.8. Security Association (Secure Channel) protocols . . . . . 48
6.7.2. Common requirements . . . . . . . . . . . . . . . . . 49 6.8.1. General considerations . . . . . . . . . . . . . . . 49
6.7.3. ACP via IPsec . . . . . . . . . . . . . . . . . . . . 50 6.8.2. Common requirements . . . . . . . . . . . . . . . . . 50
6.7.3.1. Native IPsec . . . . . . . . . . . . . . . . . . 50 6.8.3. ACP via IPsec . . . . . . . . . . . . . . . . . . . . 51
6.7.3.1.1. RFC8221 (IPsec/ESP) . . . . . . . . . . . . . 51 6.8.3.1. Native IPsec . . . . . . . . . . . . . . . . . . 51
6.7.3.1.2. RFC8247 (IKEv2) . . . . . . . . . . . . . . . 52 6.8.3.1.1. RFC8221 (IPsec/ESP) . . . . . . . . . . . . . 52
6.8.3.1.2. RFC8247 (IKEv2) . . . . . . . . . . . . . . . 53
6.7.3.2. IPsec with GRE encapsulation . . . . . . . . . . 53 6.8.3.2. IPsec with GRE encapsulation . . . . . . . . . . 54
6.7.4. ACP via DTLS . . . . . . . . . . . . . . . . . . . . 54 6.8.4. ACP via DTLS . . . . . . . . . . . . . . . . . . . . 55
6.7.5. ACP Secure Channel Profiles . . . . . . . . . . . . . 55 6.8.5. ACP Secure Channel Profiles . . . . . . . . . . . . . 57
6.8. GRASP in the ACP . . . . . . . . . . . . . . . . . . . . 56 6.9. GRASP in the ACP . . . . . . . . . . . . . . . . . . . . 57
6.8.1. GRASP as a core service of the ACP . . . . . . . . . 56 6.9.1. GRASP as a core service of the ACP . . . . . . . . . 57
6.8.2. ACP as the Security and Transport substrate for 6.9.2. ACP as the Security and Transport substrate for
GRASP . . . . . . . . . . . . . . . . . . . . . . . . 57 GRASP . . . . . . . . . . . . . . . . . . . . . . . . 58
6.8.2.1. Discussion . . . . . . . . . . . . . . . . . . . 60 6.9.2.1. Discussion . . . . . . . . . . . . . . . . . . . 61
6.9. Context Separation . . . . . . . . . . . . . . . . . . . 61 6.10. Context Separation . . . . . . . . . . . . . . . . . . . 62
6.10. Addressing inside the ACP . . . . . . . . . . . . . . . . 61 6.11. Addressing inside the ACP . . . . . . . . . . . . . . . . 62
6.10.1. Fundamental Concepts of Autonomic Addressing . . . . 61 6.11.1. Fundamental Concepts of Autonomic Addressing . . . . 62
6.10.2. The ACP Addressing Base Scheme . . . . . . . . . . . 63 6.11.2. The ACP Addressing Base Scheme . . . . . . . . . . . 64
6.10.3. ACP Zone Addressing Sub-Scheme (ACP-Zone) . . . . . 64 6.11.3. ACP Zone Addressing Sub-Scheme (ACP-Zone) . . . . . 65
6.10.4. ACP Manual Addressing Sub-Scheme (ACP-Manual) . . . 66 6.11.4. ACP Manual Addressing Sub-Scheme (ACP-Manual) . . . 67
6.10.5. ACP Vlong Addressing Sub-Scheme (ACP-VLong-8/ 6.11.5. ACP Vlong Addressing Sub-Scheme (ACP-VLong-8/
ACP-VLong-16 . . . . . . . . . . . . . . . . . . . . 67 ACP-VLong-16 . . . . . . . . . . . . . . . . . . . . 68
6.10.6. Other ACP Addressing Sub-Schemes . . . . . . . . . . 68 6.11.6. Other ACP Addressing Sub-Schemes . . . . . . . . . . 69
6.10.7. ACP Registrars . . . . . . . . . . . . . . . . . . . 69 6.11.7. ACP Registrars . . . . . . . . . . . . . . . . . . . 70
6.10.7.1. Use of BRSKI or other Mechanism/Protocols . . . 69 6.11.7.1. Use of BRSKI or other Mechanism/Protocols . . . 70
6.10.7.2. Unique Address/Prefix allocation . . . . . . . . 70 6.11.7.2. Unique Address/Prefix allocation . . . . . . . . 71
6.10.7.3. Addressing Sub-Scheme Policies . . . . . . . . . 70 6.11.7.3. Addressing Sub-Scheme Policies . . . . . . . . . 71
6.10.7.4. Address/Prefix Persistence . . . . . . . . . . . 72 6.11.7.4. Address/Prefix Persistence . . . . . . . . . . . 73
6.10.7.5. Further Details . . . . . . . . . . . . . . . . 72 6.11.7.5. Further Details . . . . . . . . . . . . . . . . 73
6.11. Routing in the ACP . . . . . . . . . . . . . . . . . . . 72 6.12. Routing in the ACP . . . . . . . . . . . . . . . . . . . 73
6.11.1. ACP RPL Profile . . . . . . . . . . . . . . . . . . 73 6.12.1. ACP RPL Profile . . . . . . . . . . . . . . . . . . 74
6.11.1.1. Overview . . . . . . . . . . . . . . . . . . . . 73 6.12.1.1. Overview . . . . . . . . . . . . . . . . . . . . 74
6.11.1.1.1. Single Instance . . . . . . . . . . . . . . 73 6.12.1.1.1. Single Instance . . . . . . . . . . . . . . 74
6.11.1.1.2. Reconvergence . . . . . . . . . . . . . . . 74 6.12.1.1.2. Reconvergence . . . . . . . . . . . . . . . 75
6.11.1.2. RPL Instances . . . . . . . . . . . . . . . . . 75 6.12.1.2. RPL Instances . . . . . . . . . . . . . . . . . 76
6.11.1.3. Storing vs. Non-Storing Mode . . . . . . . . . . 75 6.12.1.3. Storing vs. Non-Storing Mode . . . . . . . . . . 76
6.11.1.4. DAO Policy . . . . . . . . . . . . . . . . . . . 75 6.12.1.4. DAO Policy . . . . . . . . . . . . . . . . . . . 76
6.11.1.5. Path Metric . . . . . . . . . . . . . . . . . . 75 6.12.1.5. Path Metric . . . . . . . . . . . . . . . . . . 76
6.11.1.6. Objective Function . . . . . . . . . . . . . . . 75 6.12.1.6. Objective Function . . . . . . . . . . . . . . . 76
6.11.1.7. DODAG Repair . . . . . . . . . . . . . . . . . . 75 6.12.1.7. DODAG Repair . . . . . . . . . . . . . . . . . . 76
6.11.1.8. Multicast . . . . . . . . . . . . . . . . . . . 76 6.12.1.8. Multicast . . . . . . . . . . . . . . . . . . . 77
6.11.1.9. Security . . . . . . . . . . . . . . . . . . . . 76 6.12.1.9. Security . . . . . . . . . . . . . . . . . . . . 77
6.11.1.10. P2P communications . . . . . . . . . . . . . . . 76 6.12.1.10. P2P communications . . . . . . . . . . . . . . . 77
6.11.1.11. IPv6 address configuration . . . . . . . . . . . 76 6.12.1.11. IPv6 address configuration . . . . . . . . . . . 77
6.11.1.12. Administrative parameters . . . . . . . . . . . 77 6.12.1.12. Administrative parameters . . . . . . . . . . . 78
6.11.1.13. RPL Packet Information . . . . . . . . . . . . . 77 6.12.1.13. RPL Packet Information . . . . . . . . . . . . . 78
6.11.1.14. Unknown Destinations . . . . . . . . . . . . . . 77 6.12.1.14. Unknown Destinations . . . . . . . . . . . . . . 78
6.12. General ACP Considerations . . . . . . . . . . . . . . . 78 6.13. General ACP Considerations . . . . . . . . . . . . . . . 79
6.12.1. Performance . . . . . . . . . . . . . . . . . . . . 78 6.13.1. Performance . . . . . . . . . . . . . . . . . . . . 79
6.12.2. Addressing of Secure Channels . . . . . . . . . . . 78 6.13.2. Addressing of Secure Channels . . . . . . . . . . . 79
6.12.3. MTU . . . . . . . . . . . . . . . . . . . . . . . . 79 6.13.3. MTU . . . . . . . . . . . . . . . . . . . . . . . . 80
6.12.4. Multiple links between nodes . . . . . . . . . . . . 79 6.13.4. Multiple links between nodes . . . . . . . . . . . . 80
6.12.5. ACP interfaces . . . . . . . . . . . . . . . . . . . 79 6.13.5. ACP interfaces . . . . . . . . . . . . . . . . . . . 80
6.12.5.1. ACP loopback interfaces . . . . . . . . . . . . 79 6.13.5.1. ACP loopback interfaces . . . . . . . . . . . . 80
6.12.5.2. ACP virtual interfaces . . . . . . . . . . . . . 82 6.13.5.2. ACP virtual interfaces . . . . . . . . . . . . . 83
6.12.5.2.1. ACP point-to-point virtual interfaces . . . 82 6.13.5.2.1. ACP point-to-point virtual interfaces . . . 83
6.12.5.2.2. ACP multi-access virtual interfaces . . . . 82 6.13.5.2.2. ACP multi-access virtual interfaces . . . . 83
7. ACP support on L2 switches/ports (Normative) . . . . . . . . 84 7. ACP support on L2 switches/ports (Normative) . . . . . . . . 86
7.1. Why (Benefits of ACP on L2 switches) . . . . . . . . . . 84 7.1. Why (Benefits of ACP on L2 switches) . . . . . . . . . . 86
7.2. How (per L2 port DULL GRASP) . . . . . . . . . . . . . . 86 7.2. How (per L2 port DULL GRASP) . . . . . . . . . . . . . . 87
8. Support for Non-ACP Components (Normative) . . . . . . . . . 87 8. Support for Non-ACP Components (Normative) . . . . . . . . . 88
8.1. ACP Connect . . . . . . . . . . . . . . . . . . . . . . . 87 8.1. ACP Connect . . . . . . . . . . . . . . . . . . . . . . . 88
8.1.1. Non-ACP Controller / NMS system . . . . . . . . . . . 88 8.1.1. Non-ACP Controller / NMS system . . . . . . . . . . . 89
8.1.2. Software Components . . . . . . . . . . . . . . . . . 90 8.1.2. Software Components . . . . . . . . . . . . . . . . . 91
8.1.3. Auto Configuration . . . . . . . . . . . . . . . . . 91 8.1.3. Auto Configuration . . . . . . . . . . . . . . . . . 92
8.1.4. Combined ACP/Data-Plane Interface (VRF Select) . . . 92 8.1.4. Combined ACP/Data-Plane Interface (VRF Select) . . . 93
8.1.5. Use of GRASP . . . . . . . . . . . . . . . . . . . . 93 8.1.5. Use of GRASP . . . . . . . . . . . . . . . . . . . . 95
8.2. Connecting ACP islands over Non-ACP L3 networks (Remote ACP 8.2. Connecting ACP islands over Non-ACP L3 networks (Remote ACP
neighbors) . . . . . . . . . . . . . . . . . . . . . . . 94 neighbors) . . . . . . . . . . . . . . . . . . . . . . . 95
8.2.1. Configured Remote ACP neighbor . . . . . . . . . . . 94 8.2.1. Configured Remote ACP neighbor . . . . . . . . . . . 96
8.2.2. Tunneled Remote ACP Neighbor . . . . . . . . . . . . 95 8.2.2. Tunneled Remote ACP Neighbor . . . . . . . . . . . . 97
8.2.3. Summary . . . . . . . . . . . . . . . . . . . . . . . 96 8.2.3. Summary . . . . . . . . . . . . . . . . . . . . . . . 97
9. ACP Operations (Informative) . . . . . . . . . . . . . . . . 96 9. ACP Operations (Informative) . . . . . . . . . . . . . . . . 98
9.1. ACP (and BRSKI) Diagnostics . . . . . . . . . . . . . . . 97 9.1. ACP (and BRSKI) Diagnostics . . . . . . . . . . . . . . . 98
9.1.1. Secure Channel Peer diagnostics . . . . . . . . . . . 100 9.1.1. Secure Channel Peer diagnostics . . . . . . . . . . . 102
9.2. ACP Registrars . . . . . . . . . . . . . . . . . . . . . 101 9.2. ACP Registrars . . . . . . . . . . . . . . . . . . . . . 103
9.2.1. Registrar interactions . . . . . . . . . . . . . . . 101 9.2.1. Registrar interactions . . . . . . . . . . . . . . . 103
9.2.2. Registrar Parameter . . . . . . . . . . . . . . . . . 102 9.2.2. Registrar Parameter . . . . . . . . . . . . . . . . . 104
9.2.3. Certificate renewal and limitations . . . . . . . . . 103 9.2.3. Certificate renewal and limitations . . . . . . . . . 105
9.2.4. ACP Registrars with sub-CA . . . . . . . . . . . . . 104 9.2.4. ACP Registrars with sub-CA . . . . . . . . . . . . . 106
9.2.5. Centralized Policy Control . . . . . . . . . . . . . 104 9.2.5. Centralized Policy Control . . . . . . . . . . . . . 106
9.3. Enabling and disabling ACP/ANI . . . . . . . . . . . . . 105 9.3. Enabling and disabling ACP/ANI . . . . . . . . . . . . . 107
9.3.1. Filtering for non-ACP/ANI packets . . . . . . . . . . 105 9.3.1. Filtering for non-ACP/ANI packets . . . . . . . . . . 107
9.3.2. Admin Down State . . . . . . . . . . . . . . . . . . 106 9.3.2. Admin Down State . . . . . . . . . . . . . . . . . . 108
9.3.2.1. Security . . . . . . . . . . . . . . . . . . . . 107 9.3.2.1. Security . . . . . . . . . . . . . . . . . . . . 109
9.3.2.2. Fast state propagation and Diagnostics . . . . . 108 9.3.2.2. Fast state propagation and Diagnostics . . . . . 109
9.3.2.3. Low Level Link Diagnostics . . . . . . . . . . . 108 9.3.2.3. Low Level Link Diagnostics . . . . . . . . . . . 110
9.3.2.4. Power Consumption Issues . . . . . . . . . . . . 109 9.3.2.4. Power Consumption Issues . . . . . . . . . . . . 111
9.3.3. Interface level ACP/ANI enable . . . . . . . . . . . 109 9.3.3. Interface level ACP/ANI enable . . . . . . . . . . . 111
9.3.4. Which interfaces to auto-enable? . . . . . . . . . . 109 9.3.4. Which interfaces to auto-enable? . . . . . . . . . . 111
9.3.5. Node Level ACP/ANI enable . . . . . . . . . . . . . . 111 9.3.5. Node Level ACP/ANI enable . . . . . . . . . . . . . . 113
9.3.5.1. Brownfield nodes . . . . . . . . . . . . . . . . 111 9.3.5.1. Brownfield nodes . . . . . . . . . . . . . . . . 113
9.3.5.2. Greenfield nodes . . . . . . . . . . . . . . . . 112 9.3.5.2. Greenfield nodes . . . . . . . . . . . . . . . . 114
9.3.6. Undoing ANI/ACP enable . . . . . . . . . . . . . . . 113 9.3.6. Undoing ANI/ACP enable . . . . . . . . . . . . . . . 115
9.3.7. Summary . . . . . . . . . . . . . . . . . . . . . . . 113 9.3.7. Summary . . . . . . . . . . . . . . . . . . . . . . . 115
9.4. Partial or Incremental adoption . . . . . . . . . . . . . 114 9.4. Partial or Incremental adoption . . . . . . . . . . . . . 116
9.5. Configuration and the ACP (summary) . . . . . . . . . . . 115 9.5. Configuration and the ACP (summary) . . . . . . . . . . . 117
10. Summary: Benefits (Informative) . . . . . . . . . . . . . . . 116 10. Summary: Benefits (Informative) . . . . . . . . . . . . . . . 118
10.1. Self-Healing Properties . . . . . . . . . . . . . . . . 116 10.1. Self-Healing Properties . . . . . . . . . . . . . . . . 118
10.2. Self-Protection Properties . . . . . . . . . . . . . . . 118 10.2. Self-Protection Properties . . . . . . . . . . . . . . . 120
10.2.1. From the outside . . . . . . . . . . . . . . . . . . 118 10.2.1. From the outside . . . . . . . . . . . . . . . . . . 120
10.2.2. From the inside . . . . . . . . . . . . . . . . . . 119 10.2.2. From the inside . . . . . . . . . . . . . . . . . . 121
10.3. The Administrator View . . . . . . . . . . . . . . . . . 122
10.3. The Administrator View . . . . . . . . . . . . . . . . . 120 11. Security Considerations . . . . . . . . . . . . . . . . . . . 123
11. Security Considerations . . . . . . . . . . . . . . . . . . . 121 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 128
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 126 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 129
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 127 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 129
14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 127 15. Change log [RFC Editor: Please remove] . . . . . . . . . . . 130
15. Change log [RFC Editor: Please remove] . . . . . . . . . . . 128 15.1. Summary of changes since entering IESG review . . . . . 130
15.1. Summary of changes since entering IESG review . . . . . 128 15.1.1. Reviews (while in IESG review status) / status . . . 130
15.1.1. Reviews (while in IESG review status) / status . . . 128 15.1.2. BRSKI / ACP registrar related enhancements . . . . . 131
15.1.2. BRSKI / ACP registrar related enhancements . . . . . 129 15.1.3. Normative enhancements since start of IESG review . 131
15.1.3. Normative enhancements since start of IESG review . 129
15.1.4. Explanatory enhancements since start of IESG 15.1.4. Explanatory enhancements since start of IESG
review . . . . . . . . . . . . . . . . . . . . . . . 130 review . . . . . . . . . . . . . . . . . . . . . . . 132
15.2. draft-ietf-anima-autonomic-control-plane-29 . . . . . . 131 15.2. draft-ietf-anima-autonomic-control-plane-29 . . . . . . 133
15.3. draft-ietf-anima-autonomic-control-plane-28 . . . . . . 132 15.3. draft-ietf-anima-autonomic-control-plane-28 . . . . . . 135
15.4. draft-ietf-anima-autonomic-control-plane-27 . . . . . . 134 15.4. draft-ietf-anima-autonomic-control-plane-27 . . . . . . 136
15.5. draft-ietf-anima-autonomic-control-plane-26 . . . . . . 134 15.5. draft-ietf-anima-autonomic-control-plane-26 . . . . . . 137
15.6. draft-ietf-anima-autonomic-control-plane-25 . . . . . . 135 15.6. draft-ietf-anima-autonomic-control-plane-25 . . . . . . 137
15.7. draft-ietf-anima-autonomic-control-plane-24 . . . . . . 138 15.7. draft-ietf-anima-autonomic-control-plane-24 . . . . . . 141
15.8. draft-ietf-anima-autonomic-control-plane-23 . . . . . . 139 15.8. draft-ietf-anima-autonomic-control-plane-23 . . . . . . 141
15.9. draft-ietf-anima-autonomic-control-plane-22 . . . . . . 140 15.9. draft-ietf-anima-autonomic-control-plane-22 . . . . . . 143
16. Normative References . . . . . . . . . . . . . . . . . . . . 142 16. Normative References . . . . . . . . . . . . . . . . . . . . 145
17. Informative References . . . . . . . . . . . . . . . . . . . 145 17. Informative References . . . . . . . . . . . . . . . . . . . 148
Appendix A. Background and Futures (Informative) . . . . . . . . 153 Appendix A. Background and Futures (Informative) . . . . . . . . 156
A.1. ACP Address Space Schemes . . . . . . . . . . . . . . . . 154 A.1. ACP Address Space Schemes . . . . . . . . . . . . . . . . 157
A.2. BRSKI Bootstrap (ANI) . . . . . . . . . . . . . . . . . . 154 A.2. BRSKI Bootstrap (ANI) . . . . . . . . . . . . . . . . . . 157
A.3. ACP Neighbor discovery protocol selection . . . . . . . . 155 A.3. ACP Neighbor discovery protocol selection . . . . . . . . 158
A.3.1. LLDP . . . . . . . . . . . . . . . . . . . . . . . . 156 A.3.1. LLDP . . . . . . . . . . . . . . . . . . . . . . . . 159
A.3.2. mDNS and L2 support . . . . . . . . . . . . . . . . . 156 A.3.2. mDNS and L2 support . . . . . . . . . . . . . . . . . 159
A.3.3. Why DULL GRASP . . . . . . . . . . . . . . . . . . . 156 A.3.3. Why DULL GRASP . . . . . . . . . . . . . . . . . . . 159
A.4. Choice of routing protocol (RPL) . . . . . . . . . . . . 157 A.4. Choice of routing protocol (RPL) . . . . . . . . . . . . 160
A.5. ACP Information Distribution and multicast . . . . . . . 158 A.5. ACP Information Distribution and multicast . . . . . . . 161
A.6. Extending ACP channel negotiation (via GRASP) . . . . . . 159 A.6. Extending ACP channel negotiation (via GRASP) . . . . . . 162
A.7. CAs, domains and routing subdomains . . . . . . . . . . . 161 A.7. CAs, domains and routing subdomains . . . . . . . . . . . 164
A.8. Intent for the ACP . . . . . . . . . . . . . . . . . . . 162 A.8. Intent for the ACP . . . . . . . . . . . . . . . . . . . 165
A.9. Adopting ACP concepts for other environments . . . . . . 163 A.9. Adopting ACP concepts for other environments . . . . . . 166
A.10. Further (future) options . . . . . . . . . . . . . . . . 165 A.10. Further (future) options . . . . . . . . . . . . . . . . 168
A.10.1. Auto-aggregation of routes . . . . . . . . . . . . . 165 A.10.1. Auto-aggregation of routes . . . . . . . . . . . . . 168
A.10.2. More options for avoiding IPv6 Data-Plane A.10.2. More options for avoiding IPv6 Data-Plane
dependencies . . . . . . . . . . . . . . . . . . . . 165 dependencies . . . . . . . . . . . . . . . . . . . . 168
A.10.3. ACP APIs and operational models (YANG) . . . . . . . 166 A.10.3. ACP APIs and operational models (YANG) . . . . . . . 169
A.10.4. RPL enhancements . . . . . . . . . . . . . . . . . . 166 A.10.4. RPL enhancements . . . . . . . . . . . . . . . . . . 169
A.10.5. Role assignments . . . . . . . . . . . . . . . . . . 167 A.10.5. Role assignments . . . . . . . . . . . . . . . . . . 170
A.10.6. Autonomic L3 transit . . . . . . . . . . . . . . . . 167 A.10.6. Autonomic L3 transit . . . . . . . . . . . . . . . . 170
A.10.7. Diagnostics . . . . . . . . . . . . . . . . . . . . 167 A.10.7. Diagnostics . . . . . . . . . . . . . . . . . . . . 170
A.10.8. Avoiding and dealing with compromised ACP nodes . . 168 A.10.8. Avoiding and dealing with compromised ACP nodes . . 171
A.10.9. Detecting ACP secure channel downgrade attacks . . . 169 A.10.9. Detecting ACP secure channel downgrade attacks . . . 172
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 170 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 173
1. Introduction (Informative) 1. Introduction (Informative)
Autonomic Networking is a concept of self-management: Autonomic Autonomic Networking is a concept of self-management: Autonomic
functions self-configure, and negotiate parameters and settings functions self-configure, and negotiate parameters and settings
across the network. [RFC7575] defines the fundamental ideas and across the network. [RFC7575] defines the fundamental ideas and
design goals of Autonomic Networking. A gap analysis of Autonomic design goals of Autonomic Networking. A gap analysis of Autonomic
Networking is given in [RFC7576]. The reference architecture for Networking is given in [RFC7576]. The reference architecture for
Autonomic Networking in the IETF is specified in the document Autonomic Networking in the IETF is specified in the document
[I-D.ietf-anima-reference-model]. [I-D.ietf-anima-reference-model].
skipping to change at page 7, line 4 skipping to change at page 7, line 4
require a control plane which is independent of the configuration of require a control plane which is independent of the configuration of
the network they manage, to avoid impacting their own operations the network they manage, to avoid impacting their own operations
through the configuration actions they take. through the configuration actions they take.
This document describes a modular design for a self-forming, self- This document describes a modular design for a self-forming, self-
managing and self-protecting ACP, which is a virtual out-of-band managing and self-protecting ACP, which is a virtual out-of-band
network designed to be as independent as possible of configuration, network designed to be as independent as possible of configuration,
addressing and routing to avoid the self-dependency problems of addressing and routing to avoid the self-dependency problems of
current IP networks while still operating in-band on the same current IP networks while still operating in-band on the same
physical network that it is controlling and managing. The ACP design physical network that it is controlling and managing. The ACP design
is therefore intended to combine as good as possible the resilience is therefore intended to combine as well as possible the resilience
of out-of-band management networks with the low-cost of traditional of out-of-band management networks with the low-cost of traditional
IP in-band network management. The details how this is achieved are IP in-band network management. The details how this is achieved are
described in Section 6. described in Section 6.
In a fully autonomic network node without legacy control or In a fully autonomic network node without legacy control or
management functions/protocols, the Data-Plane would be for example management functions/protocols, the Data-Plane would be for example
just a forwarding plane for "Data" IPv6 packets, aka: packets other just a forwarding plane for "Data" IPv6 packets, aka: packets other
than the control and management plane packets that are forwarded by than the control and management plane packets that are forwarded by
the ACP itself. In such networks/nodes, there would be no non- the ACP itself. In such networks/nodes, there would be no non-
autonomous control or non-autonomous management plane. autonomous control or non-autonomous management plane.
Routing protocols for example would be built inside the ACP as so- Routing protocols for example would be built inside the ACP as so-
called autonomous functions via autonomous service agents, leveraging called autonomous functions via autonomous service agents, leveraging
the ACPs functions instead of implementing them seperately for each the ACPs functions instead of implementing them seperately for each
protocol: discovery, automatically established authenticated and protocol: discovery, automatically established authenticated and
encrypted local and distant peer connectivity for control and encrypted local and distant peer connectivity for control and
management traffic and common control/management protocol session and management traffic, and common control/management protocol session
presentation functions. and presentation functions.
When ACP functionality is added to nodes that have non-autonomous When ACP functionality is added to nodes that have non-autonomous
management plane and/or control plane functions (henceforth called management plane and/or control plane functions (henceforth called
non-autonomous nodes), the ACP instead is best abstracted as a non-autonomous nodes), the ACP instead is best abstracted as a
special Virtual Routing and Forwarding (VRF) instance (or virtual special Virtual Routing and Forwarding (VRF) instance (or virtual
router) and the complete pre-existing non-autonomous management and/ router) and the complete pre-existing non-autonomous management and/
or control plane is considered to be part of the Data-Plane to avoid or control plane is considered to be part of the Data-Plane to avoid
introduction of more complex, new terminology only for this case. introduction of more complex, new terminology only for this case.
Like the forwarding plane for "Data" packets, the non-autonomous Like the forwarding plane for "Data" packets, the non-autonomous
skipping to change at page 8, line 40 skipping to change at page 8, line 40
standardization in this document but were considered important to standardization in this document but were considered important to
document. There are no dependencies against Appendix A to build a document. There are no dependencies against Appendix A to build a
complete working and interoperable ACP according to this document. complete working and interoperable ACP according to this document.
The ACP provides secure IPv6 connectivity, therefore it can be used The ACP provides secure IPv6 connectivity, therefore it can be used
not only as the secure connectivity for self-management as required not only as the secure connectivity for self-management as required
for the ACP in [RFC7575], but it can also be used as the secure for the ACP in [RFC7575], but it can also be used as the secure
connectivity for traditional (centralized) management. The ACP can connectivity for traditional (centralized) management. The ACP can
be implemented and operated without any other components of autonomic be implemented and operated without any other components of autonomic
networks, except for the GRASP protocol. ACP relies on per-link DULL networks, except for the GRASP protocol. ACP relies on per-link DULL
GRASP (see Section 6.3) to autodiscover ACP neighbors, and includes GRASP (see Section 6.4) to autodiscover ACP neighbors, and includes
the ACP GRASP instance to provide service discovery for clients of the ACP GRASP instance to provide service discovery for clients of
the ACP (see Section 6.8) including for its own maintenance of ACP the ACP (see Section 6.9) including for its own maintenance of ACP
certificates. certificates.
The document "Using Autonomic Control Plane for Stable Connectivity The document "Using Autonomic Control Plane for Stable Connectivity
of Network OAM" [RFC8368] describes how the ACP alone can be used to of Network OAM" [RFC8368] describes how the ACP alone can be used to
provide secure and stable connectivity for autonomic and non- provide secure and stable connectivity for autonomic and non-
autonomic OAM applications, specifically for the case of current non- autonomic OAM applications, specifically for the case of current non-
autonomic networks/nodes. That document also explains how existing autonomic networks/nodes. That document also explains how existing
management solutions can leverage the ACP in parallel with management solutions can leverage the ACP in parallel with
traditional management models, when to use the ACP and how to traditional management models, when to use the ACP and how to
integrate with potentially IPv4 only OAM backends. integrate with potentially IPv4 only OAM backends.
skipping to change at page 9, line 35 skipping to change at page 9, line 35
Provider, Local Area Network (LAN), Metro(politan networks), Wide Provider, Local Area Network (LAN), Metro(politan networks), Wide
Area Network (WAN), Enterprise Information Technology (IT) and Area Network (WAN), Enterprise Information Technology (IT) and
->"Operational Technology" (OT) networks. The ACP can operate ->"Operational Technology" (OT) networks. The ACP can operate
equally on layer 3 equipment and on layer 2 equipment such as bridges equally on layer 3 equipment and on layer 2 equipment such as bridges
(see Section 7). The hop-by-hop authentication, integrity-protection (see Section 7). The hop-by-hop authentication, integrity-protection
and confidentiality mechanism used by the ACP is defined to be and confidentiality mechanism used by the ACP is defined to be
negotiable, therefore it can be extended to environments with negotiable, therefore it can be extended to environments with
different protocol preferences. The minimum implementation different protocol preferences. The minimum implementation
requirements in this document attempt to achieve maximum requirements in this document attempt to achieve maximum
interoperability by requiring support for multiple options depending interoperability by requiring support for multiple options depending
on the type of device: IPsec, see [RFC4301], and datagram Transport on the type of device: IPsec, see [RFC4301], and Datagram Transport
Layer Security (DTLS) version 1.2, see [RFC6347]). Layer Security (DTLS, see Section 6.8.4).
The implementation footprint of the ACP consists of Public Key The implementation footprint of the ACP consists of Public Key
Infrastructure (PKI) code for the ACP certificate, the GRASP Infrastructure (PKI) code for the ACP certificate including
protocol, UDP, TCP and TLS ([RFC5246] [RFC8446], for security and "Enrollment over Secure Transport (EST, see [RFC7030]), the GRASP
reliability of GRASP), the ACP secure channel protocol used (such as protocol, UDP, TCP and Transport Layer Security (TLS, see
IPsec or DTLS), and an instance of IPv6 packet forwarding and routing Section 6.1), for security and reliability of GRASP and for EST, the
via the Routing Protocol for Low-power and Lossy Networks (RPL), see ACP secure channel protocol used (such as IPsec or DTLS), and an
[RFC6550], that is separate from routing and forwarding for the Data- instance of IPv6 packet forwarding and routing via the Routing
Plane (user traffic). Protocol for Low-power and Lossy Networks (RPL), see [RFC6550], that
is separate from routing and forwarding for the Data-Plane (user
traffic).
The ACP uses only IPv6 to avoid complexity of dual-stack ACP The ACP uses only IPv6 to avoid complexity of dual-stack ACP
operations (IPv6/IPv4). Nevertheless, it can without any changes be operations (IPv6/IPv4). Nevertheless, it can without any changes be
integrated into even otherwise IPv4-only network devices. The Data- integrated into even otherwise IPv4-only network devices. The Data-
Plane itself would not need to change, it could continue to be IPv4 Plane itself would not need to change and it could continue to be
only. For such IPv4 only devices, the IPv6 protocol itself would be IPv4 only. For such IPv4-only devices, the IPv6 protocol itself
additional implementation footprint only used for the ACP. would be additional implementation footprint that is only required
for the ACP.
The protocol choices of the ACP are primarily based on wide use and The protocol choices of the ACP are primarily based on wide use and
support in networks and devices, well understood security properties support in networks and devices, well understood security properties
and required scalability. The ACP design is an attempt to produce and required scalability. The ACP design is an attempt to produce
the lowest risk combination of existing technologies and protocols to the lowest risk combination of existing technologies and protocols to
build a widely applicable operational network management solution. build a widely applicable operational network management solution.
RPL was chosen because it requires a smaller routing table footprint RPL was chosen because it requires a smaller routing table footprint
in large networks compared to other routing protocols with an in large networks compared to other routing protocols with an
autonomically configured single area. The deployment experience of autonomically configured single area. The deployment experience of
skipping to change at page 10, line 25 skipping to change at page 10, line 28
wide deployment experience with RPL. The profile chosen for RPL in wide deployment experience with RPL. The profile chosen for RPL in
the ACP does not leverage any RPL specific forwarding plane features the ACP does not leverage any RPL specific forwarding plane features
(IPv6 extension headers), making its implementation a pure control (IPv6 extension headers), making its implementation a pure control
plane software requirement. plane software requirement.
GRASP is the only completely novel protocol used in the ACP, and this GRASP is the only completely novel protocol used in the ACP, and this
choice was necessary because there is no existing suitable protocol choice was necessary because there is no existing suitable protocol
to provide the necessary functions to the ACP, so GRASP was developed to provide the necessary functions to the ACP, so GRASP was developed
to fill that gap. to fill that gap.
The ACP design can be applicable to (cpu, memory) constrained devices The ACP design can be applicable to devices constrained with respect
and (bitrate, reliability) constrained networks, but this document to cpu and memory, and to networks constrained with respect to
does not attempt to define the most constrained type of devices or bitrate and reliability, but this document does not attempt to define
networks to which the ACP is applicable. RPL and DTLS for ACP secure the most constrained type of devices or networks to which the ACP is
channels are two protocol choices already making ACP more applicable applicable. RPL and DTLS for ACP secure channels are two protocol
to constrained environments. Support for constrained devices in this choices already making ACP more applicable to constrained
specification is opportunistic, but not complete, because the environments. Support for constrained devices in this specification
reliable transport for GRASP (see Section 6.8.2) only specifies TCP/ is opportunistic, but not complete, because the reliable transport
TLS). See Appendix A.9 for discussions about how future standards or for GRASP (see Section 6.9.2) only specifies TCP/TLS. See
Appendix A.9 for discussions about how future standards or
proprietary extensions/variations of the ACP could better meet proprietary extensions/variations of the ACP could better meet
different expectations from those on which the current design is different expectations from those on which the current design is
based including supporting constrained devices better. based including supporting constrained devices better.
2. Acronyms and Terminology (Informative) 2. Acronyms and Terminology (Informative)
[RFC Editor: Please add ACP, BRSKI, GRASP, MASA to https://www.rfc- [RFC Editor: Please add ACP, BRSKI, GRASP, MASA to https://www.rfc-
editor.org/materials/abbrev.expansion.txt.] editor.org/materials/abbrev.expansion.txt.]
[RFC Editor: What is the recommended way to reference a hanging text, [RFC Editor: What is the recommended way to reference a hanging text,
skipping to change at page 11, line 27 skipping to change at page 11, line 21
[RFC Editor: Question: Is it possible to change the first occurrences [RFC Editor: Question: Is it possible to change the first occurrences
of [RFCxxxx] references to "rfcxxx title" [RFCxxxx]? the XML2RFC of [RFCxxxx] references to "rfcxxx title" [RFCxxxx]? the XML2RFC
format does not seem to offer such a format, but I did not want to format does not seem to offer such a format, but I did not want to
duplicate 50 first references - one reference for title mentioning duplicate 50 first references - one reference for title mentioning
and one for RFC number.] and one for RFC number.]
This document serves both as a normative specification for how ACP This document serves both as a normative specification for how ACP
nodes have to behave as well as describing requirements, benefits, nodes have to behave as well as describing requirements, benefits,
architecture and operational aspects to explain the context. architecture and operational aspects to explain the context.
Normative sections are labelled "(Normative)" and use Normative sections are labelled "(Normative)" and use BCP 14
[RFC2119]/[RFC8174] keywords. Other sections are labelled keywords. Other sections are labelled "(Informative)" and do not use
"(Informative)" and do not use those normative keywords. those normative keywords.
In the rest of the document we will refer to systems using the ACP as In the rest of the document we will refer to systems using the ACP as
"nodes". Typically such a node is a physical (network equipment) "nodes". Typically such a node is a physical (network equipment)
device, but it can equally be some virtualized system. Therefore, we device, but it can equally be some virtualized system. Therefore, we
do not refer to them as devices unless the context specifically calls do not refer to them as devices unless the context specifically calls
for a physical system. for a physical system.
This document introduces or uses the following terms (sorted This document introduces or uses the following terms (sorted
alphabetically). Terms introduced are explained on first use, so alphabetically). Terms introduced are explained on first use, so
this list is for reference only. this list is for reference only.
skipping to change at page 12, line 10 skipping to change at page 12, line 4
Functions) or completely by itself. Functions) or completely by itself.
ACP address: An IPv6 address assigned to the ACP node. It is stored ACP address: An IPv6 address assigned to the ACP node. It is stored
in the acp-node-name of the ->"ACP certificate". in the acp-node-name of the ->"ACP certificate".
ACP address range/set: The ACP address may imply a range or set of ACP address range/set: The ACP address may imply a range or set of
addresses that the node can assign for different purposes. This addresses that the node can assign for different purposes. This
address range/set is derived by the node from the format of the address range/set is derived by the node from the format of the
ACP address called the "addressing sub-scheme". ACP address called the "addressing sub-scheme".
ACP connect interface: An interface on an ACP node providing access ACP connect interface: An interface on an ACP node providing access
to the ACP for non ACP capable nodes without using an ACP secure to the ACP for non ACP capable nodes without using an ACP secure
channel. See Section 8.1.1. channel. See Section 8.1.1.
ACP domain: The ACP domain is the set of nodes with ->"ACP ACP domain: The ACP domain is the set of nodes with ->"ACP
certificates" that allow them to authenticate each other as certificates" that allow them to authenticate each other as
members of the ACP domain. See also Section 6.1.3. members of the ACP domain. See also Section 6.2.3.
ACP (ANI/AN) certificate: A [RFC5280] certificate (LDevID) carrying ACP (ANI/AN) certificate: A [RFC5280] certificate (LDevID) carrying
the acp-node-name which is used by the ACP to learn its address in the acp-node-name which is used by the ACP to learn its address in
the ACP and to derive and cryptographically assert its membership the ACP and to derive and cryptographically assert its membership
in the ACP domain. in the ACP domain.
ACP acp-node-name field: An information field in the ACP certificate ACP acp-node-name field: An information field in the ACP certificate
in which the ACP relevant information is encoded: the ACP domain in which the ACP relevant information is encoded: the ACP domain
name, the ACP IPv6 address of the node and optional additional name, the ACP IPv6 address of the node and optional additional
role attributes about the node. role attributes about the node.
ACP Loopback interface: The Loopback interface in the ACP Virtual ACP Loopback interface: The Loopback interface in the ACP Virtual
Routing and Forwarding (VRF) that has the ACP address assigned to Routing and Forwarding (VRF) that has the ACP address assigned to
it. See Section 6.12.5.1. it. See Section 6.13.5.1.
ACP network: The ACP network constitutes all the nodes that have ACP network: The ACP network constitutes all the nodes that have
access to the ACP. It is the set of active and transitively access to the ACP. It is the set of active and transitively
connected nodes of an ACP domain plus all nodes that get access to connected nodes of an ACP domain plus all nodes that get access to
the ACP of that domain via ACP edge nodes. the ACP of that domain via ACP edge nodes.
ACP (ULA) prefix(es): The /48 IPv6 address prefixes used across the ACP (ULA) prefix(es): The /48 IPv6 address prefixes used across the
ACP. In the normal/simple case, the ACP has one ULA prefix, see ACP. In the normal/simple case, the ACP has one ULA prefix, see
Section 6.10. The ACP routing table may include multiple ULA Section 6.11. The ACP routing table may include multiple ULA
prefixes if the "rsub" option is used to create addresses from prefixes if the "rsub" option is used to create addresses from
more than one ULA prefix. See Section 6.1.2. The ACP may also more than one ULA prefix. See Section 6.2.2. The ACP may also
include non-ULA prefixes if those are configured on ACP connect include non-ULA prefixes if those are configured on ACP connect
interfaces. See Section 8.1.1. interfaces. See Section 8.1.1.
ACP secure channel: A channel authenticated via ->"ACP certificates" ACP secure channel: A channel authenticated via ->"ACP certificates"
providing integrity protection and confidentiality through providing integrity protection and confidentiality through
encryption. These are established between (normally) adjacent ACP encryption. These are established between (normally) adjacent ACP
nodes to carry traffic of the ACP VRF securely and isolated from nodes to carry traffic of the ACP VRF securely and isolated from
Data-Plane traffic in-band over the same link/path as the Data- Data-Plane traffic in-band over the same link/path as the Data-
Plane. Plane.
ACP secure channel protocol: The protocol used to build an ACP ACP secure channel protocol: The protocol used to build an ACP
secure channel, e.g., Internet Key Exchange Protocol version 2 secure channel, e.g., Internet Key Exchange Protocol version 2
(IKEv2) with IPsec or Datagram Transport Layer Security (DTLS). (IKEv2) with IPsec or Datagram Transport Layer Security (DTLS).
ACP virtual interface: An interface in the ACP VRF mapped to one or ACP virtual interface: An interface in the ACP VRF mapped to one or
more ACP secure channels. See Section 6.12.5. more ACP secure channels. See Section 6.13.5.
AN "Autonomic Network": A network according to AN "Autonomic Network": A network according to
[I-D.ietf-anima-reference-model]. Its main components are ANI, [I-D.ietf-anima-reference-model]. Its main components are ANI,
Autonomic Functions and Intent. Autonomic Functions and Intent.
(AN) Domain Name: An FQDN (Fully Qualified Domain Name) in the acp- (AN) Domain Name: An FQDN (Fully Qualified Domain Name) in the acp-
node-name of the Domain Certificate. See Section 6.1.2. node-name of the Domain Certificate. See Section 6.2.2.
ANI (nodes/network): "Autonomic Network Infrastructure". The ANI is ANI (nodes/network): "Autonomic Network Infrastructure". The ANI is
the infrastructure to enable Autonomic Networks. It includes ACP, the infrastructure to enable Autonomic Networks. It includes ACP,
BRSKI and GRASP. Every Autonomic Network includes the ANI, but BRSKI and GRASP. Every Autonomic Network includes the ANI, but
not every ANI network needs to include autonomic functions beyond not every ANI network needs to include autonomic functions beyond
the ANI (nor Intent). An ANI network without further autonomic the ANI (nor Intent). An ANI network without further autonomic
functions can for example support secure zero-touch (automated) functions can for example support secure zero-touch (automated)
bootstrap and stable connectivity for SDN networks - see bootstrap and stable connectivity for SDN networks - see
[RFC8368]. [RFC8368].
ANIMA: "Autonomic Networking Integrated Model and Approach". ACP, ANIMA: "Autonomic Networking Integrated Model and Approach". ACP,
BRSKI and GRASP are specifications of the IETF ANIMA working BRSKI and GRASP are specifications of the IETF ANIMA working
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on an ANI device. The components making up the ANI (BRSKI, ACP, on an ANI device. The components making up the ANI (BRSKI, ACP,
GRASP) are also described as ASAs. GRASP) are also described as ASAs.
Autonomic Function: A function/service in an Autonomic Network (AN) Autonomic Function: A function/service in an Autonomic Network (AN)
composed of one or more ASA across one or more ANI nodes. composed of one or more ASA across one or more ANI nodes.
BRSKI: "Bootstrapping Remote Secure Key Infrastructures" BRSKI: "Bootstrapping Remote Secure Key Infrastructures"
([I-D.ietf-anima-bootstrapping-keyinfra]. A protocol extending ([I-D.ietf-anima-bootstrapping-keyinfra]. A protocol extending
EST to enable secure zero-touch bootstrap in conjunction with ACP. EST to enable secure zero-touch bootstrap in conjunction with ACP.
ANI nodes use ACP, BRSKI and GRASP. ANI nodes use ACP, BRSKI and GRASP.
CA: "Certification Authority". An entity that issues digital CA: "Certification Authority". An entity that issues digital
certificates. A CA uses its private key to sign the certificates certificates. A CA uses its private key to sign the certificates
it issues, relying parties use the public key in the CA it issues. Relying parties use the public key in the CA
certificate to validate the signature. This signing certificate certificate to validate the signature.
can be considered to be an identifier of the CA, so the term CA is
also loosely used to refer to the certificate used by the CA for
signing.
CRL: "Certificate Revocation List". A list of revoked certificates. CRL: "Certificate Revocation List". A list of revoked certificates.
Required to revoke certificates before their lifetime expires. Required to revoke certificates before their lifetime expires.
Data-Plane: The counterpoint to the ACP VRF in an ACP node: Data-Plane: The counterpoint to the ACP VRF in an ACP node:
forwarding of user traffic and in non-autonomous nodes/networks forwarding of user traffic and in non-autonomous nodes/networks
also any non-autonomous control and/or management plane functions. also any non-autonomous control and/or management plane functions.
In a fully Autonomic Network node, the Data-Plane is managed In a fully Autonomic Network node, the Data-Plane is managed
autonomically via Autonomic Functions and Intent. See Section 1 autonomically via Autonomic Functions and Intent. See Section 1
for more detailed explanations. for more detailed explanations.
device: A physical system, or physical node. device: A physical system, or physical node.
Enrollment: The process through which a node authenticates itself to Enrollment: The process through which a node authenticates itself to
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describe an IDevID in referenced materials. This term is not used describe an IDevID in referenced materials. This term is not used
in this document. in this document.
native interface: Interfaces existing on a node without native interface: Interfaces existing on a node without
configuration of the already running node. On physical nodes configuration of the already running node. On physical nodes
these are usually physical interfaces. On virtual nodes their these are usually physical interfaces. On virtual nodes their
equivalent. equivalent.
NOC: Network Operations Center. NOC: Network Operations Center.
node: A system supporting the ACP according to this document. Can node: A system supporting the ACP according to this document. Can
be virtual or physical. Physical nodes are called devices. be virtual or physical. Physical nodes are called devices.
Node-ID: The identifier of an ACP node inside that ACP. It is the Node-ID: The identifier of an ACP node inside that ACP. It is the
last 64 (see Section 6.10.3) or 78-bits (see Section 6.10.5) of last 64 (see Section 6.11.3) or 78-bits (see Section 6.11.5) of
the ACP address. the ACP address.
OAM: Operations, Administration and Management. Includes Network OAM: Operations, Administration and Management. Includes Network
Monitoring. Monitoring.
Operational Technology (OT): https://en.wikipedia.org/wiki/ Operational Technology (OT): https://en.wikipedia.org/wiki/
Operational_Technology: "The hardware and software dedicated to Operational_Technology: "The hardware and software dedicated to
detecting or causing changes in physical processes through direct detecting or causing changes in physical processes through direct
monitoring and/or control of physical devices such as valves, monitoring and/or control of physical devices such as valves,
pumps, etc.". OT networks are today in most cases well separated pumps, etc.". OT networks are today in most cases well separated
from Information Technology (IT) networks. from Information Technology (IT) networks.
out-of-band (management) network: An out-of-band network is a out-of-band (management) network: An out-of-band network is a
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root CA: "root Certification Authority". A ->"CA" for which the root CA: "root Certification Authority". A ->"CA" for which the
root CA Key update procedures of [RFC7030], Section 4.4 can be root CA Key update procedures of [RFC7030], Section 4.4 can be
applied. applied.
RPL: "IPv6 Routing Protocol for Low-Power and Lossy Networks". The RPL: "IPv6 Routing Protocol for Low-Power and Lossy Networks". The
routing protocol used in the ACP. See [RFC6550]. routing protocol used in the ACP. See [RFC6550].
(ACP/ANI/BRSKI) Registrar: An ACP registrar is an entity (software (ACP/ANI/BRSKI) Registrar: An ACP registrar is an entity (software
and/or person) that is orchestrating the enrollment of ACP nodes and/or person) that is orchestrating the enrollment of ACP nodes
with the ACP certificate. ANI nodes use BRSKI, so ANI registrars with the ACP certificate. ANI nodes use BRSKI, so ANI registrars
are also called BRSKI registrars. For non-ANI ACP nodes, the are also called BRSKI registrars. For non-ANI ACP nodes, the
registrar mechanisms are undefined by this document. See registrar mechanisms are undefined by this document. See
Section 6.10.7. Renewal and other maintenance (such as Section 6.11.7. Renewal and other maintenance (such as
revocation) of ACP certificates may be performed by other entities revocation) of ACP certificates may be performed by other entities
than registrars. EST must be supported for ACP certificate than registrars. EST must be supported for ACP certificate
renewal (see Section 6.1.5). BRSKI is an extension of EST, so renewal (see Section 6.2.5). BRSKI is an extension of EST, so
ANI/BRSKI registrars can easily support ACP domain certificate ANI/BRSKI registrars can easily support ACP domain certificate
renewal in addition to initial enrollment. renewal in addition to initial enrollment.
RPI: "RPL Packet Information". Network extension headers for use RPI: "RPL Packet Information". Network extension headers for use
with the ->"RPL" routing protocols. Not used with RPL in the ACP. with the ->"RPL" routing protocols. Not used with RPL in the ACP.
See Section 6.11.1.13. See Section 6.12.1.13.
RPL: "Routing Protocol for Low-Power and Lossy Networks". The RPL: "Routing Protocol for Low-Power and Lossy Networks". The
routing protocol used in the ACP. See Section 6.11. routing protocol used in the ACP. See Section 6.12.
sUDI: "secured Unique Device Identifier". This is another word to sUDI: "secured Unique Device Identifier". This is another word to
describe an IDevID in referenced material. This term is not used describe an IDevID in referenced material. This term is not used
in this document. in this document.
TA: "Trust Anchor". A Trust Anchor is an entity that is trusted for TA: "Trust Anchor". A Trust Anchor is an entity that is trusted for
the purpose of certificate validation. Trust Anchor Information the purpose of certificate validation. Trust Anchor Information
such as self-signed certificate(s) of the Trust Anchor is such as self-signed certificate(s) of the Trust Anchor is
configured into the ACP node as part of Enrollment. See configured into the ACP node as part of Enrollment. See
[RFC5280], Section 6.1.1. [RFC5280], Section 6.1.1.
UDI: "Unique Device Identifier". In the context of this document UDI: "Unique Device Identifier". In the context of this document
unsecured identity information of a node typically consisting of unsecured identity information of a node typically consisting of
at least device model/type and serial number, often in a vendor at least device model/type and serial number, often in a vendor
specific format. See sUDI and LDevID. specific format. See sUDI and LDevID.
ULA: (Global ID prefix) A "Unique Local Address" (ULA) is an IPv6 ULA: (Global ID prefix) A "Unique Local Address" (ULA) is an IPv6
address in the block fc00::/7, defined in [RFC4193]. It is the address in the block fc00::/7, defined in [RFC4193]. It is the
approximate IPv6 counterpart of the IPv4 private address approximate IPv6 counterpart of the IPv4 private address
([RFC1918]). The ULA Global ID prefix are the first 48-bits of a ([RFC1918]). The ULA Global ID prefix are the first 48-bits of a
ULA address. In this document it is abbreviated as "ULA prefix". ULA address. In this document it is abbreviated as "ULA prefix".
(ACP) VRF: The ACP is modeled in this document as a "Virtual Routing (ACP) VRF: The ACP is modeled in this document as a "Virtual Routing
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and Forwarding" instance (VRF). This means that it is based on a and Forwarding" instance (VRF). This means that it is based on a
"virtual router" consisting of a separate IPv6 forwarding table to "virtual router" consisting of a separate IPv6 forwarding table to
which the ACP virtual interfaces are attached and an associated which the ACP virtual interfaces are attached and an associated
IPv6 routing table separate from the Data-Plane. Unlike the VRFs IPv6 routing table separate from the Data-Plane. Unlike the VRFs
on MPLS/VPN-PE ([RFC4364]) or LISP XTR ([RFC6830]), the ACP VRF on MPLS/VPN-PE ([RFC4364]) or LISP XTR ([RFC6830]), the ACP VRF
does not have any special "core facing" functionality or routing/ does not have any special "core facing" functionality or routing/
mapping protocols shared across multiple VRFs. In vendor products mapping protocols shared across multiple VRFs. In vendor products
a VRF such as the ACP-VRF may also be referred to as a so called a VRF such as the ACP-VRF may also be referred to as a so called
VRF-lite. VRF-lite.
(ACP) Zone: An ACP zone is a set of ACP nodes using the same zone (ACP) Zone: An ACP zone is a set of ACP nodes using the same zone
field value in their ACP address according to Section 6.10.3. field value in their ACP address according to Section 6.11.3.
Zones are a mechanism to support structured addressing of ACP Zones are a mechanism to support structured addressing of ACP
addresses within the same /48-bit ULA prefix. addresses within the same /48-bit ULA prefix.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119],[RFC8174] when, and only when, they appear in all 14 [RFC2119],[RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Use Cases for an Autonomic Control Plane (Informative) 3. Use Cases for an Autonomic Control Plane (Informative)
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or mask changes, routing changes, or security policies. Today such or mask changes, routing changes, or security policies. Today such
changes require precise hop-by-hop planning. changes require precise hop-by-hop planning.
Note that specific control plane functions for the Data-Plane often Note that specific control plane functions for the Data-Plane often
want to depend on forwarding of their packets via the Data-Plane: want to depend on forwarding of their packets via the Data-Plane:
Aliveness and routing protocol signaling packets across the Data- Aliveness and routing protocol signaling packets across the Data-
Plane to verify reachability across the Data-Plane, using IPv4 Plane to verify reachability across the Data-Plane, using IPv4
signaling packets for IPv4 routing vs. IPv6 signaling packets for signaling packets for IPv4 routing vs. IPv6 signaling packets for
IPv6 routing. IPv6 routing.
Assuming appropriate implementation (see Section 6.12.2 for more Assuming appropriate implementation (see Section 6.13.2 for more
details), the ACP provides reachability that is independent of the details), the ACP provides reachability that is independent of the
Data-Plane. This allows the control plane and OAM plane to operate Data-Plane. This allows the control plane and OAM plane to operate
more robustly: more robustly:
* For management plane protocols, the ACP provides the functionality * For management plane protocols, the ACP provides the functionality
of a Virtual out-of-band (VooB) channel, by providing connectivity of a Virtual out-of-band (VooB) channel, by providing connectivity
to all nodes regardless of their Data-Plane configuration, routing to all nodes regardless of their Data-Plane configuration, routing
and forwarding tables. and forwarding tables.
* For control plane protocols, the ACP allows their operation even * For control plane protocols, the ACP allows their operation even
when the Data-Plane is temporarily faulty, or during transitional when the Data-Plane is temporarily faulty, or during transitional
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configuration and routing. Requirements 2 and 3 build on this configuration and routing. Requirements 2 and 3 build on this
requirement, but also have value on their own. requirement, but also have value on their own.
ACP2: The ACP must have a separate address space from the Data- ACP2: The ACP must have a separate address space from the Data-
Plane. Reason: traceability, debug-ability, separation from Plane. Reason: traceability, debug-ability, separation from
Data-Plane, infrastructure security (filtering based on known Data-Plane, infrastructure security (filtering based on known
address space). address space).
ACP3: The ACP must use autonomically managed address space. Reason: ACP3: The ACP must use autonomically managed address space. Reason:
easy bootstrap and setup ("autonomic"); robustness (admin easy bootstrap and setup ("autonomic"); robustness (admin
cannot break network easily). This document uses Unique Local cannot break network easily). This document uses Unique Local
Addresses (ULA) for this purpose, see [RFC4193]. Addresses (ULA) for this purpose, see [RFC4193].
ACP4: The ACP must be generic, that is it must be usable by all the ACP4: The ACP must be generic, that is it must be usable by all the
functions and protocols of the ANI. Clients of the ACP must functions and protocols of the ANI. Clients of the ACP must
not be tied to a particular application or transport protocol. not be tied to a particular application or transport protocol.
ACP5: The ACP must provide security: Messages coming through the ACP ACP5: The ACP must provide security: Messages coming through the ACP
must be authenticated to be from a trusted node, and should must be authenticated to be from a trusted node, and it is
(very strong should) be encrypted. very strongly > recommended that they be encrypted.
Explanation for ACP4: In a fully autonomic network (AN), newly Explanation for ACP4: In a fully autonomic network (AN), newly
written ASA could potentially all communicate exclusively via GRASP written ASAs could potentially all communicate exclusively via GRASP
with each other, and if that was assumed to be the only requirement with each other, and if that was assumed to be the only requirement
against the ACP, it would not need to provide IPv6 layer connectivity against the ACP, it would not need to provide IPv6 layer connectivity
between nodes, but only GRASP connectivity. Nevertheless, because between nodes, but only GRASP connectivity. Nevertheless, because
ACP also intends to support non-AN networks, it is crucial to support ACP also intends to support non-AN networks, it is crucial to support
IPv6 layer connectivity across the ACP to support any transport and IPv6 layer connectivity across the ACP to support any transport and
application layer protocols. application layer protocols.
The ACP operates hop-by-hop, because this interaction can be built on The ACP operates hop-by-hop, because this interaction can be built on
IPv6 link local addressing, which is autonomic, and has no dependency IPv6 link local addressing, which is autonomic, and has no dependency
on configuration (requirement 1). It may be necessary to have ACP on configuration (requirement 1). It may be necessary to have ACP
connectivity across non-ACP nodes, for example to link ACP nodes over connectivity across non-ACP nodes, for example to link ACP nodes over
the general Internet. This is possible, but introduces a dependency the general Internet. This is possible, but introduces a dependency
against stable/resilient routing over the non-ACP hops (see against stable/resilient routing over the non-ACP hops (see
Section 8.2). Section 8.2).
5. Overview (Informative) 5. Overview (Informative)
When a node has an ACP certificate (see Section 6.1.1) and is enabled When a node has an ACP certificate (see Section 6.2.1) and is enabled
to bring up the ACP (see Section 9.3.5), it will create its ACP to bring up the ACP (see Section 9.3.5), it will create its ACP
without any configuration as follows. For details, see Section 6 and without any configuration as follows. For details, see Section 6 and
further sections: further sections:
1. The node creates a VRF instance, or a similar virtual context for 1. The node creates a VRF instance, or a similar virtual context for
the ACP. the ACP.
2. The node assigns its ULA IPv6 address (prefix) (see Section 6.10 2. The node assigns its ULA IPv6 address (prefix) (see Section 6.11
which is learned from the acp-node-name (see Section 6.1.2) of which is learned from the acp-node-name (see Section 6.2.2) of
its ACP certificate (see Section 6.1.1) to an ACP loopback its ACP certificate (see Section 6.2.1) to an ACP loopback
interface (see Section 6.10) and connects this interface into the interface (see Section 6.11) and connects this interface into the
ACP VRF. ACP VRF.
3. The node establishes a list of candidate peer adjacencies and 3. The node establishes a list of candidate peer adjacencies and
candidate channel types to try for the adjacency. This is candidate channel types to try for the adjacency. This is
automatic for all candidate link-local adjacencies, see automatic for all candidate link-local adjacencies, see
Section 6.3 across all native interfaces (see Section 9.3.4). If Section 6.4 across all native interfaces (see Section 9.3.4). If
a candidate peer is discovered via multiple interfaces, this will a candidate peer is discovered via multiple interfaces, this will
result in one adjacency per interface. If the ACP node has result in one adjacency per interface. If the ACP node has
multiple interfaces connecting to the same subnet across which it multiple interfaces connecting to the same subnet across which it
is also operating as an L2 switch in the Data-Plane, it employs is also operating as an L2 switch in the Data-Plane, it employs
methods for ACP with L2 switching, see Section 7. methods for ACP with L2 switching, see Section 7.
4. For each entry in the candidate adjacency list, the node 4. For each entry in the candidate adjacency list, the node
negotiates a secure tunnel using the candidate channel types. negotiates a secure tunnel using the candidate channel types.
See Section 6.5. See Section 6.6.
5. The node authenticates the peer node during secure channel setup 5. The node authenticates the peer node during secure channel setup
and authorizes it to become part of the ACP according to and authorizes it to become part of the ACP according to
Section 6.1.3. Section 6.2.3.
6. Unsuccessful authentication of a candidate peer results in 6. Unsuccessful authentication of a candidate peer results in
throttled connection retries for as long as the candidate peer is throttled connection retries for as long as the candidate peer is
discoverable. See Section 6.6. discoverable. See Section 6.7.
7. Each successfully established secure channel is mapped into an 7. Each successfully established secure channel is mapped into an
ACP virtual interface, which is placed into the ACP VRF. See ACP virtual interface, which is placed into the ACP VRF. See
Section 6.12.5.2. Section 6.13.5.2.
8. Each node runs a lightweight routing protocol, see Section 6.11, 8. Each node runs a lightweight routing protocol, see Section 6.12,
to announce reachability of the ACP loopback address (or prefix) to announce reachability of the ACP loopback address (or prefix)
across the ACP. across the ACP.
9. This completes the creation of the ACP with hop-by-hop secure 9. This completes the creation of the ACP with hop-by-hop secure
tunnels, auto-addressing and auto-routing. The node is now an tunnels, auto-addressing and auto-routing. The node is now an
ACP node with a running ACP. ACP node with a running ACP.
Note: Note:
* None of the above operations (except the following explicit * None of the above operations (except the following explicit
configured ones) are reflected in the configuration of the node. configured ones) are reflected in the configuration of the node.
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information for the Data-Plane will not impact the ACP. Even information for the Data-Plane will not impact the ACP. Even
impaired ACP nodes will have a significantly reduced attack surface impaired ACP nodes will have a significantly reduced attack surface
against malicious misconfiguration because only very limited ACP or against malicious misconfiguration because only very limited ACP or
interface up/down configuration can affect the ACP, and pending on interface up/down configuration can affect the ACP, and pending on
their specific designs these type of attacks could also be their specific designs these type of attacks could also be
eliminated. See more in Section 9.3 and Section 11. eliminated. See more in Section 9.3 and Section 11.
An ACP node can be a router, switch, controller, NMS host, or any An ACP node can be a router, switch, controller, NMS host, or any
other IPv6 capable node. Initially, it MUST have its ACP other IPv6 capable node. Initially, it MUST have its ACP
certificate, as well as an (empty) ACP Adjacency Table (described in certificate, as well as an (empty) ACP Adjacency Table (described in
Section 6.2). It then can start to discover ACP neighbors and build Section 6.3). It then can start to discover ACP neighbors and build
the ACP. This is described step by step in the following sections: the ACP. This is described step by step in the following sections:
6.1. ACP Domain, Certificate and Network 6.1. Requirements for use of Transport Layer Security (TLS)
The following requirements apply to TLS required or used by ACP
components. Applicable ACP components include ACP certificate
maintenance via EST, see Section 6.2.5, TLS connections for
Certificate Revocation List (CRL) Distribution Point (CRLDP) or
Online Certificate Status Protocol (OCSP) responder (if used, see
Section 6.2.3) and ACP GRASP (see Section 6.9.2). On ANI nodes these
requirements also apply to BRSKI.
TLS MUST comply with [RFC7525] except that TLS 1.2 ([RFC5246]) is
REQUIRED and that older versions of TLS MUST NOT be used. TLS 1.3
([RFC8446]) SHOULD be supported. The choice for TLS 1.2 as the
lowest common denominator for the ACP is based on current expected
most likely availability across the wide range of candidate ACP node
types, potentially with non-agile operating system TCP/IP stacks.
TLS MUST offer TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 and
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 and MUST NOT offer options
with less than 256 bit symmetric key strength or hash strength of
less than SHA384. When TLS 1.3 is supported, TLS_AES_256_GCM_SHA384
MUST be offered and TLS_CHACHA20_POLY1305_SHA256 MAY be offered.
TLS MUST also include the "Supported Elliptic Curves" extension, it
MUST support the NIST P-256 (secp256r1(22)) and P-384 (secp384r1(24))
curves [RFC4492]. In addition, TLS clients SHOULD send an
ec_point_formats extension with a single element, "uncompressed".
6.2. ACP Domain, Certificate and Network
The ACP relies on group security. An ACP domain is a group of nodes The ACP relies on group security. An ACP domain is a group of nodes
that trust each other to participate in ACP operations such as that trust each other to participate in ACP operations such as
creating ACP secure channels in an autonomous peer-to-peer fashion creating ACP secure channels in an autonomous peer-to-peer fashion
between ACP domain members via protocols such as IPsec. To between ACP domain members via protocols such as IPsec. To
authenticate and authorize another ACP member node with access to the authenticate and authorize another ACP member node with access to the
ACP Domain, each ACP member requires keying material: An ACP node ACP Domain, each ACP member requires keying material: An ACP node
MUST have a Local Device IDentity (LDevID) certificate, henceforth MUST have a Local Device IDentity (LDevID) certificate, henceforth
called the ACP certificate and information about one or more Trust called the ACP certificate and information about one or more Trust
Anchor (TA) as required for the ACP domain membership check Anchor (TA) as required for the ACP domain membership check
(Section 6.1.3). (Section 6.2.3).
Manual keying via shared secrets is not usable for an ACP domain Manual keying via shared secrets is not usable for an ACP domain
because it would require a single shared secret across all current because it would require a single shared secret across all current
and future ACP domain members to meet the expectation of autonomous, and future ACP domain members to meet the expectation of autonomous,
peer-to-peer establishment of ACP secure channels between any ACP peer-to-peer establishment of ACP secure channels between any ACP
domain members. Such a single shared secret would be an inacceptable domain members. Such a single shared secret would be an inacceptable
security weakness. Asymmetric keying material (public keys) without security weakness. Asymmetric keying material (public keys) without
certificates does not provide the mechanisms to authenticate ACP certificates does not provide the mechanisms to authenticate ACP
domain membership in an autonomous, peer-to-peer fashion for current domain membership in an autonomous, peer-to-peer fashion for current
and future ACP domain members. and future ACP domain members.
The LDevID certificate is called the ACP certificate, the TA is the The LDevID certificate is called the ACP certificate. The TA is the
Certification Authority (CA) root certificate of the ACP domain. Certification Authority (CA) root certificate of the ACP domain.
The ACP does not mandate specific mechanisms by which this keying The ACP does not mandate specific mechanisms by which this keying
material is provisioned into the ACP node. It only requires the material is provisioned into the ACP node. It only requires the
certificate to comply with Section 6.1.1, specifically to have the certificate to comply with Section 6.2.1, specifically to have the
acp-node-name as specified in Section 6.1.2 in its domain certificate acp-node-name as specified in Section 6.2.2 in its domain certificate
as well as those of candidate ACP peers. See Appendix A.2 for more as well as those of candidate ACP peers. See Appendix A.2 for more
information about enrollment or provisioning options. information about enrollment or provisioning options.
This document uses the term ACP in many places where the Autonomic This document uses the term ACP in many places where the Autonomic
Networking reference documents [RFC7575] and Networking reference documents [RFC7575] and
[I-D.ietf-anima-reference-model] use the word autonomic. This is [I-D.ietf-anima-reference-model] use the word autonomic. This is
done because those reference documents consider (only) fully done because those reference documents consider (only) fully
autonomic networks and nodes, but support of ACP does not require autonomic networks and nodes, but support of ACP does not require
support for other components of autonomic networks except for relying support for other components of autonomic networks except for relying
on GRASP and providing security and transport for GRASP. Therefore on GRASP and providing security and transport for GRASP. Therefore
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autonomic nodes. ACP nodes do not need to be fully autonomic, but autonomic nodes. ACP nodes do not need to be fully autonomic, but
when they are, then the ACP domain is an autonomic domain. Likewise, when they are, then the ACP domain is an autonomic domain. Likewise,
[I-D.ietf-anima-reference-model] defines the term "Domain [I-D.ietf-anima-reference-model] defines the term "Domain
Certificate" as the certificate used in an autonomic domain. The ACP Certificate" as the certificate used in an autonomic domain. The ACP
certificate is that domain certificate when ACP nodes are (fully) certificate is that domain certificate when ACP nodes are (fully)
autonomic nodes. Finally, this document uses the term ACP network to autonomic nodes. Finally, this document uses the term ACP network to
refer to the network created by active ACP nodes in an ACP domain. refer to the network created by active ACP nodes in an ACP domain.
The ACP network itself can extend beyond ACP nodes through the The ACP network itself can extend beyond ACP nodes through the
mechanisms described in Section 8.1. mechanisms described in Section 8.1.
6.1.1. ACP Certificates 6.2.1. ACP Certificates
ACP certificates MUST be [RFC5280] compliant X.509 v3 ([X.509]) ACP certificates MUST be [RFC5280] compliant X.509 v3 ([X.509])
certificates. certificates.
ACP nodes MUST support handling ACP certificates, TA certificates and ACP nodes MUST support handling ACP certificates, TA certificates and
certificate chain certificates (henceforth just called certificates certificate chain certificates (henceforth just called certificates
in this section) with RSA public keys and certificates with Elliptic in this section) with RSA public keys and certificates with Elliptic
Curve (ECC) public keys. Curve (ECC) public keys.
ACP nodes MUST NOT support certificates with RSA public keys of less ACP nodes MUST NOT support certificates with RSA public keys of less
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Some ACP functions such as GRASP peer-2-peer across the ACP require Some ACP functions such as GRASP peer-2-peer across the ACP require
end-to-end/any-to-any authentication/authorization, therefore ECC can end-to-end/any-to-any authentication/authorization, therefore ECC can
only reliably be used in the ACP when it MUST be supported on all ACP only reliably be used in the ACP when it MUST be supported on all ACP
nodes. RSA signatures are mandatory to be supported also for ECC nodes. RSA signatures are mandatory to be supported also for ECC
certificates because CAs themselves may not support ECC yet. certificates because CAs themselves may not support ECC yet.
The ACP certificate SHOULD be used for any authentication between The ACP certificate SHOULD be used for any authentication between
nodes with ACP domain certificates (ACP nodes and NOC nodes) where a nodes with ACP domain certificates (ACP nodes and NOC nodes) where a
required authorization condition is ACP domain membership, such as required authorization condition is ACP domain membership, such as
ACP node to NOC/OAM end-to-end security and ASA to ASA end-to-end ACP node to NOC/OAM end-to-end security and ASA to ASA end-to-end
security. Section 6.1.3 defines this "ACP domain membership check". security. Section 6.2.3 defines this "ACP domain membership check".
The uses of this check that are standardized in this document are for The uses of this check that are standardized in this document are for
the establishment of hop-by-hop ACP secure channels (Section 6.6) and the establishment of hop-by-hop ACP secure channels (Section 6.7) and
for ACP GRASP (Section 6.8.2) end-to-end via TLS 1.2 ([RFC5246]). for ACP GRASP (Section 6.9.2) end-to-end via TLS.
The ACP domain membership check requires a minimum amount of elements The ACP domain membership check requires a minimum amount of elements
in a certificate as described in Section 6.1.3. The identity of a in a certificate as described in Section 6.2.3. The identity of a
node in the ACP is carried via the acp-node-name as defined in node in the ACP is carried via the acp-node-name as defined in
Section 6.1.2. Section 6.2.2.
In support of ECDH key establishment, ACP certificates with ECC keys In support of ECDH key establishment, ACP certificates with ECC keys
MUST indicate to be Elliptic Curve Diffie-Hellman capable (ECDH): If MUST indicate to be Elliptic Curve Diffie-Hellman capable (ECDH): If
the X.509v3 keyUsage extension is present, the keyAgreement bit MUST the X.509v3 keyUsage extension is present, the keyAgreement bit MUST
be set. be set.
Any other fields of the ACP certificate are to be populated as Any other fields of the ACP certificate are to be populated as
required by [RFC5280]: As long as they are compliant with [RFC5280], required by [RFC5280]: As long as they are compliant with [RFC5280],
any other field of an ACP certificate can be set as desired by the any other field of an ACP certificate can be set as desired by the
operator of the ACP domain through appropriate ACP registrar/ACP CA operator of the ACP domain through appropriate ACP registrar/ACP CA
skipping to change at page 25, line 39 skipping to change at page 25, line 44
the "serialNumber" contains usually device type information that may the "serialNumber" contains usually device type information that may
help to faster determine working exploits/attacks against the device. help to faster determine working exploits/attacks against the device.
Note that there is no intention to constrain authorization within the Note that there is no intention to constrain authorization within the
ACP or autonomic networks using the ACP to just the ACP domain ACP or autonomic networks using the ACP to just the ACP domain
membership check as defined in this document. It can be extended or membership check as defined in this document. It can be extended or
modified with additional requirements. Such future authorizations modified with additional requirements. Such future authorizations
can use and require additional elements in certificates or policies can use and require additional elements in certificates or policies
or even additional certificates. See the additional check agagainst or even additional certificates. See the additional check agagainst
the id-kp-cmcRA [RFC6402] extended key usage attribute the id-kp-cmcRA [RFC6402] extended key usage attribute
(Section 6.1.5) and for possible future extensions, see (Section 6.2.5) and for possible future extensions, see
Appendix A.10.5. Appendix A.10.5.
6.1.2. ACP Certificate AcpNodeName 6.2.2. ACP Certificate AcpNodeName
acp-node-name = local-part "@" acp-domain-name acp-node-name = local-part "@" acp-domain-name
local-part = [ acp-address ] [ "+" rsub extensions ] local-part = [ acp-address ] [ "+" rsub extensions ]
acp-address = 32HEXDIG | "0" ; HEXDIG as of RFC5234 section B.1 acp-address = 32HEXDIG | "0" ; HEXDIG as of RFC5234 section B.1
rsub = [ <subdomain> ] ; <subdomain> as of RFC1034, section 3.5 rsub = [ <subdomain> ] ; <subdomain> as of RFC1034, section 3.5
acp-domain-name = ; <domain> ; as of RFC 1034, section 3.5 acp-domain-name = ; <domain> ; as of RFC 1034, section 3.5
extensions = *( "+" extension ) extensions = *( "+" extension )
extension = 1*etext ; future standard definition. extension = 1*etext ; future standard definition.
etext = ALPHA / DIGIT / ; Printable US-ASCII etext = ALPHA / DIGIT / ; Printable US-ASCII
"!" / "#" / "$" / "%" / "&" / "'" / "!" / "#" / "$" / "%" / "&" / "'" /
"*" / "-" / "/" / "=" / "?" / "^" / "*" / "-" / "/" / "=" / "?" / "^" /
skipping to change at page 26, line 34 skipping to change at page 26, line 34
acp-node-name = fd89b714f3db00000200000064000000 acp-node-name = fd89b714f3db00000200000064000000
+area51.research@acp.example.com +area51.research@acp.example.com
acp-domain-name = acp.example.com acp-domain-name = acp.example.com
routing-subdomain = area51.research.acp.example.com routing-subdomain = area51.research.acp.example.com
Figure 2: ACP Node Name ABNF Figure 2: ACP Node Name ABNF
acp-node-name in above Figure 2 is the ABNF ([RFC5234]) definition of acp-node-name in above Figure 2 is the ABNF ([RFC5234]) definition of
the ACP Node Name. An ACP certificate MUST carry this information. the ACP Node Name. An ACP certificate MUST carry this information.
It MUST be encoded as a subjectAltName / otherName / AcpNodeName as It MUST be encoded as a subjectAltName / otherName / AcpNodeName as
described in Section 6.1.2.1. described in Section 6.2.2.1.
Nodes complying with this specification MUST be able to receive their Nodes complying with this specification MUST be able to receive their
ACP address through the domain certificate, in which case their own ACP address through the domain certificate, in which case their own
ACP certificate MUST have a 32HEXDIG acp-address field. Acp-address ACP certificate MUST have a 32HEXDIG acp-address field. Acp-address
is case insensitive because ABNF HEXDIG is. It is recommended to is case insensitive because ABNF HEXDIG is. It is recommended to
encode acp-address with lower case letters. Nodes complying with encode acp-address with lower case letters. Nodes complying with
this specification MUST also be able to authenticate nodes as ACP this specification MUST also be able to authenticate nodes as ACP
domain members or ACP secure channel peers when they have a 0-value domain members or ACP secure channel peers when they have a 0-value
acp-address field and as ACP domain members (but not as ACP secure acp-address field and as ACP domain members (but not as ACP secure
channel peers) when the acp-address field is omitted from their channel peers) when the acp-address field is omitted from their
AcpNodeName. See Section 6.1.3. AcpNodeName. See Section 6.2.3.
acp-domain-name is used to indicate the ACP Domain across which ACP acp-domain-name is used to indicate the ACP Domain across which ACP
nodes authenticate and authorize each other, for example to build ACP nodes authenticate and authorize each other, for example to build ACP
secure channels to each other, see Section 6.1.3. acp-domain-name secure channels to each other, see Section 6.2.3. acp-domain-name
SHOULD be the FQDN of an Internet domain owned by the network SHOULD be the FQDN of an Internet domain owned by the network
administration of the ACP and ideally reserved to only be used for administration of the ACP and ideally reserved to only be used for
the ACP. In this specification it serves to be a name for the ACP the ACP. In this specification it serves to be a name for the ACP
that ideally is globally unique. When acp-domain-name is a globally that ideally is globally unique. When acp-domain-name is a globally
unique name, collision of ACP addresses across different ACP domains unique name, collision of ACP addresses across different ACP domains
can only happen due to ULA hash collisions (see Section 6.10.2). can only happen due to ULA hash collisions (see Section 6.11.2).
Using different acp-domain-names, operators can distinguish multiple Using different acp-domain-names, operators can distinguish multiple
ACP even when using the same TA. ACP even when using the same TA.
To keep the encoding simple, there is no consideration for To keep the encoding simple, there is no consideration for
internationalized acp-domain-names. The acp-node-name is not internationalized acp-domain-names. The acp-node-name is not
intended for end user consumption, and there is no protection against intended for end user consumption, and there is no protection against
someone not owning a domain name to simply choose it. Instead, it someone not owning a domain name to simply choose it. Instead, it
serves as a hash seed for the ULA and for diagnostics to the serves as a hash seed for the ULA and for diagnostics to the
operator. Therefore, any operator owning only an internationalized operator. Therefore, any operator owning only an internationalized
domain name should be able to pick an equivalently unique 7-bit ASCII domain name should be able to pick an equivalently unique 7-bit ASCII
skipping to change at page 28, line 47 skipping to change at page 28, line 47
[RFC7585], [RFC4985], [RFC8398]). [RFC7585], [RFC4985], [RFC8398]).
3.3 The element required for the ACP should minimize the risk of 3.3 The element required for the ACP should minimize the risk of
being misinterpreted by other uses of the LDevID being misinterpreted by other uses of the LDevID
certificate. It also must not be misinterpreted to actually certificate. It also must not be misinterpreted to actually
be an email address, hence the use of the otherName / be an email address, hence the use of the otherName /
rfc822Name option in the certificate would be inappropriate. rfc822Name option in the certificate would be inappropriate.
See section 4.2.1.6 of [RFC5280] for details on the subjectAltName See section 4.2.1.6 of [RFC5280] for details on the subjectAltName
field. field.
6.1.2.1. AcpNodeName ASN.1 Module 6.2.2.1. AcpNodeName ASN.1 Module
The following ASN.1 module normatively specifies the AcpNodeName The following ASN.1 module normatively specifies the AcpNodeName
structure. This specification uses the ASN.1 definitions from structure. This specification uses the ASN.1 definitions from
[RFC5912] with the 2002 ASN.1 notation used in that document. [RFC5912] with the 2002 ASN.1 notation used in that document.
[RFC5912] updates normative documents using older ASN.1 notation. [RFC5912] updates normative documents using older ASN.1 notation.
ANIMA-ACP-2020 ANIMA-ACP-2020
{ iso(1) identified-organization(3) dod(6) { iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-anima-acpnodename-2020(IANA1) } id-mod-anima-acpnodename-2020(IANA1) }
skipping to change at page 29, line 44 skipping to change at page 29, line 44
id-on-AcpNodeName OBJECT IDENTIFIER ::= { id-on IANA2 } id-on-AcpNodeName OBJECT IDENTIFIER ::= { id-on IANA2 }
AcpNodeName ::= IA5String (SIZE (1..MAX)) AcpNodeName ::= IA5String (SIZE (1..MAX))
-- AcpNodeName as specified in this document carries the -- AcpNodeName as specified in this document carries the
-- acp-node-name as specified in the ABNF in Section 6.1.2 -- acp-node-name as specified in the ABNF in Section 6.1.2
END END
Figure 3 Figure 3
6.1.3. ACP domain membership check 6.2.3. ACP domain membership check
The following points constitute the ACP domain membership check of a The following points constitute the ACP domain membership check of a
candidate peer via its certificate: candidate peer via its certificate:
1: The peer has proved ownership of the private key associated with 1: The peer has proved ownership of the private key associated with
the certificate's public key. This check is performed by the the certificate's public key. This check is performed by the
security association protocol used, for example [RFC7296], section security association protocol used, for example [RFC7296], section
2.15. 2.15.
2: The peer's certificate passes certificate path validation as 2: The peer's certificate passes certificate path validation as
defined in [RFC5280], section 6 against one of the TA associated defined in [RFC5280], section 6 against one of the TA associated
with the ACP node's ACP certificate (see Section 6.1.4 below). with the ACP node's ACP certificate (see Section 6.2.4 below).
This includes verification of the validity (lifetime) of the This includes verification of the validity (lifetime) of the
certificates in the path. certificates in the path.
3: If the peer's certificate indicates a Certificate Revocation List 3: If the peer's certificate indicates a Certificate Revocation List
(CRL) Distribution Point (CRLDP) ([RFC5280], section 4.2.1.13) or (CRL) Distribution Point (CRLDP) ([RFC5280], section 4.2.1.13) or
Online Certificate Status Protocol (OCSP) responder ([RFC5280], Online Certificate Status Protocol (OCSP) responder ([RFC5280],
section 4.2.2.1), then the peer's certificate MUST be valid section 4.2.2.1), then the peer's certificate MUST be valid
according to those mechanisms when they are available: An OCSP according to those mechanisms when they are available: An OCSP
check for the peer's certificate across the ACP must succeed or check for the peer's certificate across the ACP must succeed or
the peer certificate must not be listed in the CRL retrieved from the peer certificate must not be listed in the CRL retrieved from
the CRLDP. These mechanisms are not available when the ACP node the CRLDP. These mechanisms are not available when the ACP node
has no ACP or non-ACP connectivity to retrieve a current CRL or has no ACP or non-ACP connectivity to retrieve a current CRL or
access an OCSP responder and the security association protocol access an OCSP responder and the security association protocol
itself has also no way to communicate CRL or OCSP check. itself has also no way to communicate CRL or OCSP check.
Retries to learn revocation via OCSP/CRL SHOULD be made using the Retries to learn revocation via OCSP/CRL SHOULD be made using the
same backoff as described in Section 6.6. If and when the ACP same backoff as described in Section 6.7. If and when the ACP
node then learns that an ACP peer's certificate is invalid for node then learns that an ACP peer's certificate is invalid for
which rule 3 had to be skipped during ACP secure channel which rule 3 had to be skipped during ACP secure channel
establishment, then the ACP secure channel to that peer MUST be establishment, then the ACP secure channel to that peer MUST be
closed even if this peer is the only connectivity to access CRL/ closed even if this peer is the only connectivity to access CRL/
OCSP. This applies (of course) to all ACP secure channels to this OCSP. This applies (of course) to all ACP secure channels to this
peer if there are multiple. The ACP secure channel connection peer if there are multiple. The ACP secure channel connection
MUST be retried periodically to support the case that the neighbor MUST be retried periodically to support the case that the neighbor
acquires a new, valid certificate. acquires a new, valid certificate.
4: The peer's certificate has a syntactically valid acp-node-name 4: The peer's certificate has a syntactically valid acp-node-name
field and the acp-domain-name in that peer's acp-node-name is the field and the acp-domain-name in that peer's acp-node-name is the
skipping to change at page 31, line 37 skipping to change at page 31, line 37
* Steps 1...4 authorize to build any secure connection between * Steps 1...4 authorize to build any secure connection between
members of the same ACP domain except for ACP secure channels. members of the same ACP domain except for ACP secure channels.
* Step 5 is the additional verification of the presence of an ACP * Step 5 is the additional verification of the presence of an ACP
address as necessary for ACP secure channels. address as necessary for ACP secure channels.
* Steps 1...5 therefore authorize to build an ACP secure channel. * Steps 1...5 therefore authorize to build an ACP secure channel.
For brevity, the remainder of this document refers to this process For brevity, the remainder of this document refers to this process
only as authentication instead of as authentication and only as authentication instead of as authentication and
authorization. authorization.
6.1.3.1. Realtime clock and Time Validation 6.2.3.1. Realtime clock and Time Validation
An ACP node with a realtime clock in which it has confidence, MUST An ACP node with a realtime clock in which it has confidence, MUST
check the time stamps when performing ACP domain membership check check the time stamps when performing ACP domain membership check
such as as the certificate validity period in step 1. and the such as as the certificate validity period in step 1. and the
respective times in step 4 for revocation information (e.g., respective times in step 4 for revocation information (e.g.,
signingTimes in CMS signatures). signingTimes in CMS signatures).
An ACP node without such a realtime clock MAY ignore those time stamp An ACP node without such a realtime clock MAY ignore those time stamp
validation steps if it does not know the current time. Such an ACP validation steps if it does not know the current time. Such an ACP
node SHOULD obtain the current time in a secured fashion, such as via node SHOULD obtain the current time in a secured fashion, such as via
skipping to change at page 32, line 27 skipping to change at page 32, line 27
their link-local addresses SHOULD primarily run NTP across the ACP their link-local addresses SHOULD primarily run NTP across the ACP
and provide NTP time across the ACP only when they have a trusted and provide NTP time across the ACP only when they have a trusted
time source. Details for such NTP procedures are beyond the scope of time source. Details for such NTP procedures are beyond the scope of
this specification. this specification.
Beside ACP domain membership check, the ACP itself has no dependency Beside ACP domain membership check, the ACP itself has no dependency
against knowledge of the current time, but protocols and services against knowledge of the current time, but protocols and services
using the ACP will likeley have the need to know the current time. using the ACP will likeley have the need to know the current time.
For example event logging. For example event logging.
6.1.4. Trust Anchors (TA) 6.2.4. Trust Anchors (TA)
ACP nodes need TA information according to [RFC5280], section 6.1.1 ACP nodes need TA information according to [RFC5280], section 6.1.1
(d), typically in the form of one or more certificate of the TA to (d), typically in the form of one or more certificate of the TA to
perform certificate path validation as required by Section 6.1.3, perform certificate path validation as required by Section 6.2.3,
rule 2. TA information MUST be provisioned to an ACP node (together rule 2. TA information MUST be provisioned to an ACP node (together
with its ACP domain certificate) by an ACP Registrar during initial with its ACP domain certificate) by an ACP Registrar during initial
enrollment of a candidate ACP node. ACP nodes MUST also support enrollment of a candidate ACP node. ACP nodes MUST also support
renewal of TA information via Enrollment over Secure Transport (EST, renewal of TA information via EST as described below in
see [RFC7030]), as described below in Section 6.1.5. Section 6.2.5.
The required information about a TA can consist of not only a single, The required information about a TA can consist of not only a single,
but multiple certificates as required for dealing with CA certificate but multiple certificates as required for dealing with CA certificate
renewals as explained in Section 4.4 of CMP ([RFC4210]). renewals as explained in Section 4.4 of CMP ([RFC4210]).
A certificate path is a chain of certificates starting at the ACP A certificate path is a chain of certificates starting at the ACP
certificate (leaf/end-entity) followed by zero or more intermediate certificate (leaf/end-entity) followed by zero or more intermediate
CA certificates and ending with the TA information, which are CA certificates and ending with the TA information, which are
typically one or two the self-signed certificates of the TA. The CA typically one or two the self-signed certificates of the TA. The CA
that signs the ACP certificate is called the assigning CA. If there that signs the ACP certificate is called the assigning CA. If there
skipping to change at page 33, line 37 skipping to change at page 33, line 37
requirements typically exclude public CA, because they in general do requirements typically exclude public CA, because they in general do
not support the notion of trusted registrars vouching for the not support the notion of trusted registrars vouching for the
correctness of the fields of a requested certificate or would by correctness of the fields of a requested certificate or would by
themselves not be capable to validate the correctness of otherName / themselves not be capable to validate the correctness of otherName /
AcpNodeName. AcpNodeName.
A single owner can operate multiple independent ACP domains from the A single owner can operate multiple independent ACP domains from the
same set of TA. Registrars must then know which ACP a node needs to same set of TA. Registrars must then know which ACP a node needs to
be enrolled into. be enrolled into.
6.1.5. Certificate and Trust Anchor Maintenance 6.2.5. Certificate and Trust Anchor Maintenance
ACP nodes MUST support renewal of their Certificate and TA ACP nodes MUST support renewal of their Certificate and TA
information via EST ("Enrollment over Secure Transport", see information via EST and MAY support other mechanisms. See
[RFC7030]) and MAY support other mechanisms. An ACP network MUST Section 6.1 for TLS requirements. An ACP network MUST have at least
have at least one ACP node supporting EST server functionality across one ACP node supporting EST server functionality across the ACP so
the ACP so that EST renewal is useable. that EST renewal is useable.
ACP nodes SHOULD be able to remember the IPv6 locator parameters of ACP nodes SHOULD be able to remember the IPv6 locator parameters of
the O_IPv6_LOCATOR in GRASP of the EST server from which they last the O_IPv6_LOCATOR in GRASP of the EST server from which they last
renewed their ACP certificate. They SHOULD provide the ability for renewed their ACP certificate. They SHOULD provide the ability for
these EST server parameters to also be set by the ACP Registrar (see these EST server parameters to also be set by the ACP Registrar (see
Section 6.10.7) that initially enrolled the ACP device with its ACP Section 6.11.7) that initially enrolled the ACP device with its ACP
certificate. When BRSKI (see certificate. When BRSKI (see
[I-D.ietf-anima-bootstrapping-keyinfra]) is used, the IPv6 locator of [I-D.ietf-anima-bootstrapping-keyinfra]) is used, the IPv6 locator of
the BRSKI registrar from the BRSKI TLS connection SHOULD be the BRSKI registrar from the BRSKI TLS connection SHOULD be
remembered and used for the next renewal via EST if that registrar remembered and used for the next renewal via EST if that registrar
also announces itself as an EST server via GRASP (see next section) also announces itself as an EST server via GRASP (see next section)
on its ACP address. on its ACP address.
The EST server MUST present a certificate that is passing ACP domain The EST server MUST present a certificate that is passing ACP domain
membership check in its TLS connection setup (Section 6.1.3, rules membership check in its TLS connection setup (Section 6.2.3, rules
1..4, not rule 5 as this is not for an ACP secure channel setup). 1..4, not rule 5 as this is not for an ACP secure channel setup).
The EST server certificate MUST also contain the id-kp-cmcRA The EST server certificate MUST also contain the id-kp-cmcRA
[RFC6402] extended key usage attribute and the EST client MUST check [RFC6402] extended key usage attribute and the EST client MUST check
its presence. its presence.
The additional check against the id-kp-cmcRA extended key usage The additional check against the id-kp-cmcRA extended key usage
extension field ensures that clients do not fall prey to an illicit extension field ensures that clients do not fall prey to an illicit
EST server. While such illicit EST servers should not be able to EST server. While such illicit EST servers should not be able to
support certificate signing requests (as they are not able to elicit support certificate signing requests (as they are not able to elicit
a signing response from a valid CA), such an illicit EST server would a signing response from a valid CA), such an illicit EST server would
be able to provide faked CA certificates to EST clients that need to be able to provide faked CA certificates to EST clients that need to
renew their CA certificates when they expire. renew their CA certificates when they expire.
Note that EST servers supporting multiple ACP domains will need to Note that EST servers supporting multiple ACP domains will need to
have for each of these ACP domains a separate certificate and respond have for each of these ACP domains a separate certificate and respond
on a different transport address (IPv6 address and/or TCP port), but on a different transport address (IPv6 address and/or TCP port), but
this is easily automated on the EST server as long as the CA does not this is easily automated on the EST server as long as the CA does not
restrict registrars to request certificates with the id-kp-cmcRA restrict registrars to request certificates with the id-kp-cmcRA
extended usage extension for themselves. extended usage extension for themselves.
6.1.5.1. GRASP objective for EST server 6.2.5.1. GRASP objective for EST server
ACP nodes that are EST servers MUST announce their service via GRASP ACP nodes that are EST servers MUST announce their service via GRASP
in the ACP through M_FLOOD messages. See [I-D.ietf-anima-grasp], in the ACP through M_FLOOD messages. See [I-D.ietf-anima-grasp],
section 2.8.11 for the definition of this message type: section 2.8.11 for the definition of this message type:
Example: Example:
[M_FLOOD, 12340815, h'fd89b714f3db00002000000640000001', 210000, [M_FLOOD, 12340815, h'fd89b714f3db0000200000064000001', 210000,
[["SRV.est", 4, 255 ], [["SRV.est", 4, 255 ],
[O_IPv6_LOCATOR, [O_IPv6_LOCATOR,
h'fd89b714f3db00002000000640000001', IPPROTO_TCP, 443]] h'fd89b714f3db0000200000064000001', IPPROTO_TCP, 443]]
] ]
Figure 4: GRASP SRV.est example Figure 4: GRASP SRV.est example
The formal definition of the objective in Concise data definition The formal definition of the objective in Concise data definition
language (CDDL) (see [RFC8610]) is as follows: language (CDDL) (see [RFC8610]) is as follows:
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
+[objective, (locator-option / [])]] +[objective, (locator-option / [])]]
; see example above and explanation ; see example above and explanation
skipping to change at page 36, line 5 skipping to change at page 36, line 5
receiver tries to connect to this dead service before this timeout, receiver tries to connect to this dead service before this timeout,
it will experience a failing connection and use that as an indication it will experience a failing connection and use that as an indication
that the service instance is dead and select another instance of the that the service instance is dead and select another instance of the
same service instead (from another GRASP announcement). same service instead (from another GRASP announcement).
The "SRV.est" objective(s) SHOULD only be announced when the ACP node The "SRV.est" objective(s) SHOULD only be announced when the ACP node
knows that it can successfully communicate with a CA to perform the knows that it can successfully communicate with a CA to perform the
EST renewal/rekeying operations for the ACP domain. See also EST renewal/rekeying operations for the ACP domain. See also
Section 11. Section 11.
6.1.5.2. Renewal 6.2.5.2. Renewal
When performing renewal, the node SHOULD attempt to connect to the When performing renewal, the node SHOULD attempt to connect to the
remembered EST server. If that fails, it SHOULD attempt to connect remembered EST server. If that fails, it SHOULD attempt to connect
to an EST server learned via GRASP. The server with which to an EST server learned via GRASP. The server with which
certificate renewal succeeds SHOULD be remembered for the next certificate renewal succeeds SHOULD be remembered for the next
renewal. renewal.
Remembering the last renewal server and preferring it provides Remembering the last renewal server and preferring it provides
stickiness which can help diagnostics. It also provides some stickiness which can help diagnostics. It also provides some
protection against off-path compromised ACP members announcing bogus protection against off-path compromised ACP members announcing bogus
information into GRASP. information into GRASP.
Renewal of certificates SHOULD start after less than 50% of the Renewal of certificates SHOULD start after less than 50% of the
domain certificate lifetime so that network operations has ample time domain certificate lifetime so that network operations has ample time
to investigate and resolve any problems that causes a node to not to investigate and resolve any problems that causes a node to not
renew its domain certificate in time - and to allow prolonged periods renew its domain certificate in time - and to allow prolonged periods
of running parts of a network disconnected from any CA. of running parts of a network disconnected from any CA.
6.1.5.3. Certificate Revocation Lists (CRLs) 6.2.5.3. Certificate Revocation Lists (CRLs)
The ACP node SHOULD support revocation through CRL(s) via HTTP from The ACP node SHOULD support revocation through CRL(s) via HTTP from
one or more CRL Distribution Points (CRLDP). The CRLDP(s) MUST be one or more CRL Distribution Points (CRLDP). The CRLDP(s) MUST be
indicated in the Domain Certificate when used. If the CRLDP URL uses indicated in the Domain Certificate when used. If the CRLDP URL uses
an IPv6 address (ULA address when using the addressing rules an IPv6 address (ULA address when using the addressing rules
specified in this document), the ACP node will connect to the CRLDP specified in this document), the ACP node will connect to the CRLDP
via the ACP. If the CRLDP uses a domain name, the ACP node will via the ACP. If the CRLDP uses a domain name, the ACP node will
connect to the CRLDP via the Data-Plane. connect to the CRLDP via the Data-Plane.
It is common to use domain names for CRLDP(s), but there is no It is common to use domain names for CRLDP(s), but there is no
skipping to change at page 37, line 10 skipping to change at page 37, line 10
case, HTTPS may be chosen to provide confidentiality, especially when case, HTTPS may be chosen to provide confidentiality, especially when
making the CRL available via the Data-Plane. Authentication and making the CRL available via the Data-Plane. Authentication and
authorization SHOULD use ACP certificates and ACP domain membership authorization SHOULD use ACP certificates and ACP domain membership
check. The CRLDP MAY omit the CRL verification during authentication check. The CRLDP MAY omit the CRL verification during authentication
of the peer to permit retrieval of the CRL by an ACP node with of the peer to permit retrieval of the CRL by an ACP node with
revoked ACP certificate. This can allow for that (ex) ACP node to revoked ACP certificate. This can allow for that (ex) ACP node to
quickly discover its ACP certificate revocation. This may violate quickly discover its ACP certificate revocation. This may violate
the desired need-to-know requirement though. ACP nodes MAY support the desired need-to-know requirement though. ACP nodes MAY support
CRLDP operations via HTTPS. CRLDP operations via HTTPS.
6.1.5.4. Lifetimes 6.2.5.4. Lifetimes
Certificate lifetime may be set to shorter lifetimes than customary Certificate lifetime may be set to shorter lifetimes than customary
(1 year) because certificate renewal is fully automated via ACP and (1 year) because certificate renewal is fully automated via ACP and
EST. The primary limiting factor for shorter certificate lifetimes EST. The primary limiting factor for shorter certificate lifetimes
is load on the EST server(s) and CA. It is therefore recommended is load on the EST server(s) and CA. It is therefore recommended
that ACP certificates are managed via a CA chain where the assigning that ACP certificates are managed via a CA chain where the assigning
CA has enough performance to manage short lived certificates. See CA has enough performance to manage short lived certificates. See
also Section 9.2.4 for discussion about an example setup achieving also Section 9.2.4 for discussion about an example setup achieving
this. See also [I-D.ietf-acme-star]. this. See also [I-D.ietf-acme-star].
When certificate lifetimes are sufficiently short, such as few hours, When certificate lifetimes are sufficiently short, such as few hours,
certificate revocation may not be necessary, allowing to simplify the certificate revocation may not be necessary, allowing to simplify the
overall certificate maintenance infrastructure. overall certificate maintenance infrastructure.
See Appendix A.2 for further optimizations of certificate maintenance See Appendix A.2 for further optimizations of certificate maintenance
when BRSKI can be used ("Bootstrapping Remote Secure Key when BRSKI can be used ("Bootstrapping Remote Secure Key
Infrastructures", see [I-D.ietf-anima-bootstrapping-keyinfra]). Infrastructures", see [I-D.ietf-anima-bootstrapping-keyinfra]).
6.1.5.5. Re-enrollment 6.2.5.5. Re-enrollment
An ACP node may determine that its ACP certificate has expired, for An ACP node may determine that its ACP certificate has expired, for
example because the ACP node was powered down or disconnected longer example because the ACP node was powered down or disconnected longer
than its certificate lifetime. In this case, the ACP node SHOULD than its certificate lifetime. In this case, the ACP node SHOULD
convert to a role of a re-enrolling candidate ACP node. convert to a role of a re-enrolling candidate ACP node.
In this role, the node does maintain the TA and certificate chain In this role, the node does maintain the TA and certificate chain
associated with its ACP certificate exclusively for the purpose of associated with its ACP certificate exclusively for the purpose of
re-enrollment, and attempts (or waits) to get re-enrolled with a new re-enrollment, and attempts (or waits) to get re-enrolled with a new
ACP certificate. The details depend on the mechanisms/protocols used ACP certificate. The details depend on the mechanisms/protocols used
by the ACP Registrars. by the ACP Registrars.
Please refer to Section 6.10.7 and Please refer to Section 6.11.7 and
[I-D.ietf-anima-bootstrapping-keyinfra] for explanations about ACP [I-D.ietf-anima-bootstrapping-keyinfra] for explanations about ACP
Registrars and vouchers as used in the following text. When ACP is Registrars and vouchers as used in the following text. When ACP is
intended to be used without BRSKI, the details about BRSKI and intended to be used without BRSKI, the details about BRSKI and
vouchers in the following text can be skipped. vouchers in the following text can be skipped.
When BRSKI is used (i.e.: on ACP nodes that are ANI nodes), the re- When BRSKI is used (i.e.: on ACP nodes that are ANI nodes), the re-
enrolling candidate ACP node would attempt to enroll like a candidate enrolling candidate ACP node would attempt to enroll like a candidate
ACP node (BRSKI pledge), but instead of using the ACP nodes IDevID ACP node (BRSKI pledge), but instead of using the ACP nodes IDevID
certificate, it SHOULD first attempt to use its ACP domain certificate, it SHOULD first attempt to use its ACP domain
certificate in the BRSKI TLS authentication. The BRSKI registrar MAY certificate in the BRSKI TLS authentication. The BRSKI registrar MAY
skipping to change at page 39, line 5 skipping to change at page 39, line 5
certificate and ACP TA SHOULD therefore be maintained and used for certificate and ACP TA SHOULD therefore be maintained and used for
re-enrollment until new keying material is enrolled. re-enrollment until new keying material is enrolled.
When using BRSKI or other protocol/mechanisms supporting vouchers, When using BRSKI or other protocol/mechanisms supporting vouchers,
maintaining existing TA information allows for re-enrollment of maintaining existing TA information allows for re-enrollment of
expired ACP certificates to be more lightweight, especially in expired ACP certificates to be more lightweight, especially in
environments where repeated acquisition of vouchers during the environments where repeated acquisition of vouchers during the
lifetime of ACP nodes may be operationally expensive or otherwise lifetime of ACP nodes may be operationally expensive or otherwise
undesirable. undesirable.
6.1.5.6. Failing Certificates 6.2.5.6. Failing Certificates
An ACP certificate is called failing in this document, if/when the An ACP certificate is called failing in this document, if/when the
ACP node to which the certificate was issued can determine that it ACP node to which the certificate was issued can determine that it
was revoked (or explicitly not renewed), or in the absence of such was revoked (or explicitly not renewed), or in the absence of such
explicit local diagnostics, when the ACP node fails to connect to explicit local diagnostics, when the ACP node fails to connect to
other ACP nodes in the same ACP domain using its ACP certificate. other ACP nodes in the same ACP domain using its ACP certificate.
For connection failures to determine the ACP certificate as the For connection failures to determine the ACP certificate as the
culprit, the peer should pass the domain membership check culprit, the peer should pass the domain membership check
(Section 6.1.3) and other reasons for the connection failure can be (Section 6.2.3) and other reasons for the connection failure can be
excluded because of the connection error diagnostics. excluded because of the connection error diagnostics.
This type of failure can happen during setup/refresh of a secure ACP This type of failure can happen during setup/refresh of a secure ACP
channel connections or any other use of the ACP certificate, such as channel connections or any other use of the ACP certificate, such as
for the TLS connection to an EST server for the renewal of the ACP for the TLS connection to an EST server for the renewal of the ACP
domain certificate. domain certificate.
Example reasons for failing certificates that the ACP node can only Example reasons for failing certificates that the ACP node can only
discover through connection failure are that the domain certificate discover through connection failure are that the domain certificate
or any of its signing certificates could have been revoked or may or any of its signing certificates could have been revoked or may
have expired, but the ACP node cannot self-diagnose this condition have expired, but the ACP node cannot self-diagnose this condition
directly. Revocation information or clock synchronization may only directly. Revocation information or clock synchronization may only
be available across the ACP, but the ACP node cannot build ACP secure be available across the ACP, but the ACP node cannot build ACP secure
channels because ACP peers reject the ACP node's domain certificate. channels because ACP peers reject the ACP node's domain certificate.
ACP nodes SHOULD support the option to determines whether its ACP ACP nodes SHOULD support the option to determines whether its ACP
certificate is failing, and when it does, put itself into the role of certificate is failing, and when it does, put itself into the role of
a re-enrolling candidate ACP node as explained above a re-enrolling candidate ACP node as explained above
(Section 6.1.5.5). (Section 6.2.5.5).
6.2. ACP Adjacency Table 6.3. ACP Adjacency Table
To know to which nodes to establish an ACP channel, every ACP node To know to which nodes to establish an ACP channel, every ACP node
maintains an adjacency table. The adjacency table contains maintains an adjacency table. The adjacency table contains
information about adjacent ACP nodes, at a minimum: Node-ID information about adjacent ACP nodes, at a minimum: Node-ID
(identifier of the node inside the ACP, see Section 6.10.3 and (identifier of the node inside the ACP, see Section 6.11.3 and
Section 6.10.5), interface on which neighbor was discovered (by GRASP Section 6.11.5), interface on which neighbor was discovered (by GRASP
as explained below), link-local IPv6 address of neighbor on that as explained below), link-local IPv6 address of neighbor on that
interface, certificate (including acp-node-name). An ACP node MUST interface, certificate (including acp-node-name). An ACP node MUST
maintain this adjacency table. This table is used to determine to maintain this adjacency table. This table is used to determine to
which neighbor an ACP connection is established. which neighbor an ACP connection is established.
Where the next ACP node is not directly adjacent (i.e., not on a link Where the next ACP node is not directly adjacent (i.e., not on a link
connected to this node), the information in the adjacency table can connected to this node), the information in the adjacency table can
be supplemented by configuration. For example, the Node-ID and IP be supplemented by configuration. For example, the Node-ID and IP
address could be configured. See Section 8.2. address could be configured. See Section 8.2.
The adjacency table MAY contain information about the validity and The adjacency table MAY contain information about the validity and
trust of the adjacent ACP node's certificate. However, subsequent trust of the adjacent ACP node's certificate. However, subsequent
steps MUST always start with the ACP domain membership check against steps MUST always start with the ACP domain membership check against
the peer (see Section 6.1.3). the peer (see Section 6.2.3).
The adjacency table contains information about adjacent ACP nodes in The adjacency table contains information about adjacent ACP nodes in
general, independently of their domain and trust status. The next general, independently of their domain and trust status. The next
step determines to which of those ACP nodes an ACP connection should step determines to which of those ACP nodes an ACP connection should
be established. be established.
6.3. Neighbor Discovery with DULL GRASP 6.4. Neighbor Discovery with DULL GRASP
[RFC Editor: GRASP draft is in RFC editor queue, waiting for [RFC Editor: GRASP draft is in RFC editor queue, waiting for
dependencies, including ACP. Please ensure that references to I- dependencies, including ACP. Please ensure that references to I-
D.ietf-anima-grasp that include section number references (throughout D.ietf-anima-grasp that include section number references (throughout
this document) will be updated in case any last-minute changes in this document) will be updated in case any last-minute changes in
GRASP would make those section references change. GRASP would make those section references change.
Discovery Unsolicited Link-Local (DULL) GRASP is a limited subset of Discovery Unsolicited Link-Local (DULL) GRASP is a limited subset of
GRASP intended to operate across an insecure link-local scope. See GRASP intended to operate across an insecure link-local scope. See
section 2.5.2 of [I-D.ietf-anima-grasp] for its formal definition. section 2.5.2 of [I-D.ietf-anima-grasp] for its formal definition.
skipping to change at page 42, line 41 skipping to change at page 42, line 41
IKEv2 is the actual protocol used to negotiate an Internet Protocol IKEv2 is the actual protocol used to negotiate an Internet Protocol
security architecture (IPsec) connection. GRASP therefore indicates security architecture (IPsec) connection. GRASP therefore indicates
"IKEv2" and not "IPsec". If "IPsec" was used, this too could mean "IKEv2" and not "IPsec". If "IPsec" was used, this too could mean
use of the obsolete older version IKE (v1) ([RFC2409]). IKEv2 has an use of the obsolete older version IKE (v1) ([RFC2409]). IKEv2 has an
IANA assigned port number 500, but in the above example, the IANA assigned port number 500, but in the above example, the
candidate ACP neighbor is offering ACP secure channel negotiation via candidate ACP neighbor is offering ACP secure channel negotiation via
IKEv2 on port 15000 (purely to show through the example that GRASP IKEv2 on port 15000 (purely to show through the example that GRASP
allows to indicate the port number and it does not have to be the allows to indicate the port number and it does not have to be the
IANA assigned one). IANA assigned one).
"DTLS" indicates DTLS 1.2. This can also be a newer version of the There is no default UDP port for DTLS, it is always locally assigned
protocol as long as it can negotiate down to version 1.2 in the by the node. For further details about the "DTLS" secure channel
presence of a peer only speaking DTLS 1.2. There is no default UDP protocol, see Section 6.8.4.
port for DTLS, it is always locally assigned by the node. For
details, see Section 6.7.4.
If a locator is included, it MUST be an O_IPv6_LOCATOR, and the IPv6 If a locator is included, it MUST be an O_IPv6_LOCATOR, and the IPv6
address MUST be the same as the initiator address (these are DULL address MUST be the same as the initiator address (these are DULL
requirements to minimize third party DoS attacks). requirements to minimize third party DoS attacks).
The secure channel methods defined in this document use the The secure channel methods defined in this document use the
objective-values of "IKEv2" and "DTLS". There is no distinction objective-values of "IKEv2" and "DTLS". There is no distinction
between IKEv2 native and GRE-IKEv2 because this is purely negotiated between IKEv2 native and GRE-IKEv2 because this is purely negotiated
via IKEv2. via IKEv2.
skipping to change at page 43, line 39 skipping to change at page 43, line 34
Note that a node serving both as an ACP node and BRSKI Join Proxy may Note that a node serving both as an ACP node and BRSKI Join Proxy may
choose to distribute the "AN_ACP" objective and the respective BRSKI choose to distribute the "AN_ACP" objective and the respective BRSKI
in the same M_FLOOD message, since GRASP allows multiple objectives in the same M_FLOOD message, since GRASP allows multiple objectives
in one message. This may be impractical though if ACP and BRSKI in one message. This may be impractical though if ACP and BRSKI
operations are implemented via separate software modules / ASAs. operations are implemented via separate software modules / ASAs.
The result of the discovery is the IPv6 link-local address of the The result of the discovery is the IPv6 link-local address of the
neighbor as well as its supported secure channel protocols (and non- neighbor as well as its supported secure channel protocols (and non-
standard port they are running on). It is stored in the ACP standard port they are running on). It is stored in the ACP
Adjacency Table (see Section 6.2), which then drives the further Adjacency Table (see Section 6.3), which then drives the further
building of the ACP to that neighbor. building of the ACP to that neighbor.
Note that the DULL GRASP objective described intentionally does not Note that the DULL GRASP objective described intentionally does not
include ACP nodes ACP certificate even though this would be useful include ACP nodes ACP certificate even though this would be useful
for diagnostics and to simplify the security exchange in ACP secure for diagnostics and to simplify the security exchange in ACP secure
channel security association protocols (see Section 6.7). The reason channel security association protocols (see Section 6.8). The reason
is that DULL GRASP messages are periodically multicasted across IPv6 is that DULL GRASP messages are periodically multicasted across IPv6
subnets and full certificates could easily lead to fragmented IPv6 subnets and full certificates could easily lead to fragmented IPv6
DULL GRASP multicast packets due to the size of a certificate. This DULL GRASP multicast packets due to the size of a certificate. This
would be highly undesirable. would be highly undesirable.
6.4. Candidate ACP Neighbor Selection 6.5. Candidate ACP Neighbor Selection
An ACP node determines to which other ACP nodes in the adjacency An ACP node determines to which other ACP nodes in the adjacency
table it should attempt to build an ACP connection. This is based on table it should attempt to build an ACP connection. This is based on
the information in the ACP Adjacency table. the information in the ACP Adjacency table.
The ACP is established exclusively between nodes in the same domain. The ACP is established exclusively between nodes in the same domain.
This includes all routing subdomains. Appendix A.7 explains how ACP This includes all routing subdomains. Appendix A.7 explains how ACP
connections across multiple routing subdomains are special. connections across multiple routing subdomains are special.
The result of the candidate ACP neighbor selection process is a list The result of the candidate ACP neighbor selection process is a list
of adjacent or configured autonomic neighbors to which an ACP channel of adjacent or configured autonomic neighbors to which an ACP channel
should be established. The next step begins that channel should be established. The next step begins that channel
establishment. establishment.
6.5. Channel Selection 6.6. Channel Selection
To avoid attacks, initial discovery of candidate ACP peers cannot To avoid attacks, initial discovery of candidate ACP peers cannot
include any non-protected negotiation. To avoid re-inventing and include any non-protected negotiation. To avoid re-inventing and
validating security association mechanisms, the next step after validating security association mechanisms, the next step after
discovering the address of a candidate neighbor can only be to try discovering the address of a candidate neighbor can only be to try
first to establish a security association with that neighbor using a first to establish a security association with that neighbor using a
well-known security association method. well-known security association method.
From the use-cases it seems clear that not all type of ACP nodes can From the use-cases it seems clear that not all type of ACP nodes can
or need to connect directly to each other or are able to support or or need to connect directly to each other or are able to support or
skipping to change at page 45, line 13 skipping to change at page 45, line 9
secure channel protocols). secure channel protocols).
To ensure that the selection of the secure channel protocols always To ensure that the selection of the secure channel protocols always
succeeds in a predictable fashion without blocking, the following succeeds in a predictable fashion without blocking, the following
rules apply: rules apply:
* An ACP node may choose to attempt to initiate the different * An ACP node may choose to attempt to initiate the different
feasible ACP secure channel protocols it supports according to its feasible ACP secure channel protocols it supports according to its
local policies sequentially or in parallel, but it MUST support local policies sequentially or in parallel, but it MUST support
acting as a responder to all of them in parallel. acting as a responder to all of them in parallel.
* Once the first secure channel protocol succeeds, the two peers * Once the first ACP secure channel protocol connection to a
know each other's certificates because they are used by all secure specific peer IPv6 address passes peer authentication, the two
channel protocols for mutual authentication. The node with the peers know each other's certificate because those ACP certificates
lower Node-ID in the ACP address of its ACP certificate becomes are used by all secure channel protocols for mutual
Bob, the one with the higher Node-ID in the certificate Alice. A authentication. The peer with the higher Node-ID in the
peer with an omitted ACP address field in its ACP certificate ACPNodeName of its ACP certificate takes on the role of the
becomes Bob (this specification does not define such peers, only Decider towards the peer. The other peer takes on the role of the
the interoperability with them). Follower. The Decider selects which secure channel protocol to
* Bob becomes passive, he does not attempt to further initiate ACP ultimately use.
secure channel protocols with Alice and does not consider it to be * The Follower becomes passive: it does not attempt to further
an error when Alice closes secure channels. Alice becomes the initiate ACP secure channel protocol connections with the Decider
active party, continues to attempt setting up secure channel and does not consider it to be an error when the Decider closes
protocols with Bob until she arrives at the best one from her view secure channels. The Decider becomes the active party, continues
that also works with Bob. to attempt setting up secure channel protocols with the Follower.
This process terminates when the Decider arrives at the "best" ACP
secure channel connection option that also works with the Follower
("best" from the Deciders point of view).
* A peer with a "0" acp-address in its AcpNodeName takes on the role
of Follower when peering with a node that has a non-"0" acp-
address (note that this specification does not fully define the
behavior of ACP secure channel negitation for nodes with a "0" ACP
address field, it only defines interoperability with such ACP
nodes).
For example, originally Bob could have been the initiator of one ACP In a simple example, ACP peer Node 1 attempts to initiate an IPsec
secure channel protocol that Bob prefers and the security association via IKEv2 connection to peer Node 2. The IKEv2 authentication
succeeded. The roles of Bob and Alice are then assigned and the succeeds. Node 1 has the lower ACP address and becomes the Follower.
connection setup is completed. The protocol could for example be Node 2 becomes the Decider. IKEv2 might not be the preferred ACP
IPsec via IKEv2 ("IP security", see [RFC4301] and "Internet Key secure channel protocol for the Decider Node 2. Node 2 would
Exchange protocol version 2", see [RFC7296]. It is now up to Alice therefore proceed to attempt secure channel setups with (in its view)
to decide how to proceed. Even if the IPsec connection from Bob more preferred protocol options (e.g., DTLS/UDP). If any such
succeeded, Alice might prefer another secure protocol over IPsec preferred ACP secure channel connection of the Decider succeeds, it
(e.g., FOOBAR), and try to set that up with Bob. If that preference would close the IPsec connection. If Node 2 has no preferred
of Alice succeeds, she would close the IPsec connection. If no protocol option over IPsec, or no such connection attempt from Node 2
better protocol attempt succeeds, she would keep the IPsec to Node 1 succeeds, Node 2 would keep the IPsec connection and use
connection. it.
The Decider SHOULD NOT send actual payload packets across a secure
channel until it has decided to use it. The Follower MAY delay
linking the ACP secure channel into the ACP virtual interface until
it sees the first payload packet from the Decider up to a maximum of
5 seconds to avoid unnecessarily linking a secure channel that will
be terminated as undesired by the Decider shortly afterwards.
The following sequence of steps show this example in more detail. The following sequence of steps show this example in more detail.
Each step is tagged with [<step#>{:<connection>}]. The connection is Each step is tagged with [<step#>{:<connection>}]. The connection is
included to easier distinguish which of the two competing connections included to easier distinguish which of the two competing connections
the step belong to, one initiated by Node 1, one initiated by Node 2. the step belong to, one initiated by Node 1, one initiated by Node 2.
[1] Node 1 sends GRASP AN_ACP message to announce itself [1] Node 1 sends GRASP AN_ACP message to announce itself
[2] Node 2 sends GRASP AN_ACP message to announce itself [2] Node 2 sends GRASP AN_ACP message to announce itself
skipping to change at page 46, line 24 skipping to change at page 47, line 24
[5] Node 1 receives [2] from Node 2 [5] Node 1 receives [2] from Node 2
[6:C2] Because of [5], Node 1 starts as initiator on its [6:C2] Because of [5], Node 1 starts as initiator on its
preferred secure channel protocol towards Node 2. preferred secure channel protocol towards Node 2.
Connection C2. Connection C2.
[7:C1] Node1 and Node2 have authenticated each others [7:C1] Node1 and Node2 have authenticated each others
certificate on connection C1 as valid ACP peers. certificate on connection C1 as valid ACP peers.
[8:C1] Node 1 certificate has lower ACP Node-ID than Node2, [8:C1] Node 1 certificate has lower ACP Node-ID than Node2, therefore
therefore Node 1 considers itself Bob and Node 2 Alice Node 1 considers itself the Follower and Node 2 the Decider
on connection C1. Connection setup C1 is completed. on connection C1. Connection setup C1 is completed.
[9] Node 1 (Bob)) refrains from attempting any further secure [9] Node 1 refrains from attempting any further secure channel
channel connections to Node 2 (Alice) as learned from [2] connections to Node 2 (the Decider) as learned from [2]
because it knows from [8:C1] that it is Bob relative because it knows from [8:C1] that it is the Follower
to Node 1. relative to Node 1.
[10:C2] Node1 and Node2 have authenticated each others [10:C2] Node1 and Node2 have authenticated each others
certificate on connection C2 (like [7:C1]). certificate on connection C2 (like [7:C1]).
[11:C2] Node 1 certificate has lower ACP Node-ID than Node2, [11:C2] Node 1 certificate has lower ACP Node-ID than Node2,
therefore Node 1 considers itself Bob and Node 2 Alice therefore Node 1 considers itself the Follower and Node 2 the
on connection C2, but they also identify that C2 is to the Decider on connection C2, but they also identify that C2 is
same mutual peer as their C1, so this has no further impact: to the same mutual peer as their C1, so this has no further
the roles Alice and Bob where already assigned between these impact: the roles Decider and Follower where already assigned
two peers by [8:C1]. between these two peers by [8:C1].
[12:C2] Node 2 (Alice) closes C1. Node 1 (Bob) is fine with this, [12:C2] Node 2 (the Decider) closes C1. Node 1 is fine with this,
because of his role as Bob (since [8:C1]). because of its role as the Follower (from [8:C1]).
[13] Node 2 (Alice) and Node 1 (Bob) start data transfer across [13] Node 2 (the Decider) and Node 1 (the Follower) start data
C2, which makes it become a secure channel for the ACP. transfer across C2, which makes it become a secure channel
for the ACP.
Figure 8: Secure Channel sequence of steps Figure 8: Secure Channel sequence of steps
All this negotiation is in the context of an "L2 interface". Alice All this negotiation is in the context of an "L2 interface". The
and Bob will build ACP connections to each other on every "L2 Decider and Follower will build ACP connections to each other on
interface" that they both connect to. An autonomic node MUST NOT every "L2 interface" that they both connect to. An autonomic node
assume that neighbors with the same L2 or link-local IPv6 addresses MUST NOT assume that neighbors with the same L2 or link-local IPv6
on different L2 interfaces are the same node. This can only be addresses on different L2 interfaces are the same node. This can
determined after examining the certificate after a successful only be determined after examining the certificate after a successful
security association attempt. security association attempt.
6.6. Candidate ACP Neighbor verification The Decider SHOULD NOT suppress attempting a particular ACP secure
channel protocol connection on one L2 interface because this type of
ACP secure channel connection has failed to the peer with the same
ACP certificate on another L2 interface: Not only the supported ACP
secure channel protocol options may be different on the same ACP peer
across different L2 interfaces, but also error conditions may cause
inconsistent failures across different L2 interfaces. Avoiding such
connection attempt optimizations can therefore help to increase
robustness in the case of errors.
6.7. Candidate ACP Neighbor verification
Independent of the security association protocol chosen, candidate Independent of the security association protocol chosen, candidate
ACP neighbors need to be authenticated based on their domain ACP neighbors need to be authenticated based on their domain
certificate. This implies that any secure channel protocol MUST certificate. This implies that any secure channel protocol MUST
support certificate based authentication that can support the ACP support certificate based authentication that can support the ACP
domain membership check as defined in Section 6.1.3. If it fails, domain membership check as defined in Section 6.2.3. If it fails,
the connection attempt is aborted and an error logged. Attempts to the connection attempt is aborted and an error logged. Attempts to
reconnect MUST be throttled. The RECOMMENDED default is exponential reconnect MUST be throttled. The RECOMMENDED default is exponential
base 2 backoff with a minimum delay of 10 seconds and a maximum delay base 2 backoff with a minimum delay of 10 seconds and a maximum delay
of 640 seconds. of 640 seconds.
Failure to authenticate an ACP neighbor when acting in the role of a Failure to authenticate an ACP neighbor when acting in the role of a
responder of the security authentication protocol MUST NOT impact the responder of the security authentication protocol MUST NOT impact the
attempts of the ACP node to attempt establishing a connection as an attempts of the ACP node to attempt establishing a connection as an
initiator. Only failed connection attempts as an initiator must initiator. Only failed connection attempts as an initiator must
cause throttling. This rule is meant to increase resilience of cause throttling. This rule is meant to increase resilience of
secure channel creation. Section 6.5 shows how simultaneous mutual secure channel creation. Section 6.6 shows how simultaneous mutual
secure channel setup collisions are resolved. secure channel setup collisions are resolved.
6.7. Security Association (Secure Channel) protocols 6.8. Security Association (Secure Channel) protocols
This section describes how ACP nodes establish secured data This section describes how ACP nodes establish secured data
connections to automatically discovered or configured peers in the connections to automatically discovered or configured peers in the
ACP. Section 6.3 above described how IPv6 subnet adjacent peers are ACP. Section 6.4 above described how IPv6 subnet adjacent peers are
discovered automatically. Section 8.2 describes how non IPv6 subnet discovered automatically. Section 8.2 describes how non IPv6 subnet
adjacent peers can be configured. adjacent peers can be configured.
Section 6.12.5.2 describes how secure channels are mapped to virtual Section 6.13.5.2 describes how secure channels are mapped to virtual
IPv6 subnet interfaces in the ACP. The simple case is to map every IPv6 subnet interfaces in the ACP. The simple case is to map every
ACP secure channel into a separate ACP point-to-point virtual ACP secure channel into a separate ACP point-to-point virtual
interface Section 6.12.5.2.1. When a single subnet has multiple ACP interface Section 6.13.5.2.1. When a single subnet has multiple ACP
peers this results in multiple ACP point-to-point virtual interfaces peers this results in multiple ACP point-to-point virtual interfaces
across that underlying multi-party IPv6 subnet. This can be across that underlying multi-party IPv6 subnet. This can be
optimized with ACP multi-access virtual interfaces optimized with ACP multi-access virtual interfaces
(Section 6.12.5.2.2) but the benefits of that optimization may not (Section 6.13.5.2.2) but the benefits of that optimization may not
justify the complexity of that option. justify the complexity of that option.
6.7.1. General considerations 6.8.1. General considerations
Due to Channel Selection (Section 6.5), ACP can support an evolving Due to Channel Selection (Section 6.6), ACP can support an evolving
set of security association protocols and does not require support set of security association protocols and does not require support
for a single network wide MTI. ACP nodes only need to implement for a single network wide MTI. ACP nodes only need to implement
those protocols required to interoperate with their candidate peers, those protocols required to interoperate with their candidate peers,
not with potentially any node in the ACP domain. See Section 6.7.5 not with potentially any node in the ACP domain. See Section 6.8.5
for an example of this. for an example of this.
The degree of security required on every hop of an ACP network needs The degree of security required on every hop of an ACP network needs
to be consistent across the network so that there is no designated to be consistent across the network so that there is no designated
"weakest link" because it is that "weakest link" that would otherwise "weakest link" because it is that "weakest link" that would otherwise
become the designated point of attack. When the secure channel become the designated point of attack. When the secure channel
protection on one link is compromised, it can be used to send/receive protection on one link is compromised, it can be used to send/receive
packets across the whole ACP network. Therefore, even though the packets across the whole ACP network. Therefore, even though the
security association protocols can be different, their minimum degree security association protocols can be different, their minimum degree
of security should be comparable. of security should be comparable.
skipping to change at page 49, line 5 skipping to change at page 50, line 8
Strong physical security of a link may stand in where cryptographic Strong physical security of a link may stand in where cryptographic
security is infeasible. As there is no secure mechanism to security is infeasible. As there is no secure mechanism to
automatically discover strong physical security solely between two automatically discover strong physical security solely between two
peers, it can only be used with explicit configuration and that peers, it can only be used with explicit configuration and that
configuration too could become an attack vector. This document configuration too could become an attack vector. This document
therefore only specifies with ACP connect (Section 8.1) one therefore only specifies with ACP connect (Section 8.1) one
explicitly configured mechanism without any secure channel explicitly configured mechanism without any secure channel
association protocol - for the case where both the link and the nodes association protocol - for the case where both the link and the nodes
attached to it have strong physical security. attached to it have strong physical security.
6.7.2. Common requirements 6.8.2. Common requirements
The authentication of peers in any security association protocol MUST The authentication of peers in any security association protocol MUST
use the ACP certificate according to Section 6.1.3. Because auto- use the ACP certificate according to Section 6.2.3. Because auto-
discovery of candidate ACP neighbors via GRASP (see Section 6.3) as discovery of candidate ACP neighbors via GRASP (see Section 6.4) as
specified in this document does not communicate the neighbors ACP specified in this document does not communicate the neighbors ACP
certificate, and ACP nodes may not (yet) have any other network certificate, and ACP nodes may not (yet) have any other network
connectivity to retrieve certificates, any security association connectivity to retrieve certificates, any security association
protocol MUST use a mechanism to communicate the certificate directly protocol MUST use a mechanism to communicate the certificate directly
instead of relying on a referential mechanism such as communicating instead of relying on a referential mechanism such as communicating
only a hash and/or URL for the certificate. only a hash and/or URL for the certificate.
A security association protocol MUST use Forward Secrecy (whether A security association protocol MUST use Forward Secrecy (whether
inherently or as part of a profile of the security association inherently or as part of a profile of the security association
protocol). protocol).
skipping to change at page 50, line 17 skipping to change at page 51, line 20
options SHOULD be eliminated that are not necessary to support options SHOULD be eliminated that are not necessary to support
devices that are expected to be able to support the ACP to minimize devices that are expected to be able to support the ACP to minimize
implementation complexity. For example, definitions for security implementation complexity. For example, definitions for security
protocols often include old/inferior security options required only protocols often include old/inferior security options required only
to interoperate with existing devices that will not be a able to to interoperate with existing devices that will not be a able to
update to the currently preferred security options. Such old/ update to the currently preferred security options. Such old/
inferior security options do not need to be supported when a security inferior security options do not need to be supported when a security
association protocol is first specified for the ACP, strengthening association protocol is first specified for the ACP, strengthening
the "weakest link" and simplifying ACP implementation overhead. the "weakest link" and simplifying ACP implementation overhead.
6.7.3. ACP via IPsec 6.8.3. ACP via IPsec
An ACP node announces its ability to support IPsec, negotiated via An ACP node announces its ability to support IPsec, negotiated via
IKEv2, as the ACP secure channel protocol using the "IKEv2" IKEv2, as the ACP secure channel protocol using the "IKEv2"
objective-value in the "AN_ACP" GRASP objective. objective-value in the "AN_ACP" GRASP objective.
The ACP usage of IPsec and IKEv2 mandates a profile with a narrow set The ACP usage of IPsec and IKEv2 mandates a profile with a narrow set
of options of the current standards-track usage guidance for IPsec of options of the current standards-track usage guidance for IPsec
[RFC8221] and IKEv2 [RFC8247]. These option result in stringent [RFC8221] and IKEv2 [RFC8247]. These option result in stringent
security properties and can exclude deprecated/legacy algorithms security properties and can exclude deprecated/legacy algorithms
because there is no need for interoperability with legacy equipment because there is no need for interoperability with legacy equipment
for ACP secure channels. Any such backward compatibility would lead for ACP secure channels. Any such backward compatibility would lead
only to increased attack surface and implementation complexity, for only to increased attack surface and implementation complexity, for
no benefit. no benefit.
6.7.3.1. Native IPsec 6.8.3.1. Native IPsec
An ACP node that is supporting native IPsec MUST use IPsec in tunnel An ACP node that is supporting native IPsec MUST use IPsec in tunnel
mode, negotiated via IKEv2, and with IPv6 payload (e.g., ESP Next mode, negotiated via IKEv2, and with IPv6 payload (e.g., ESP Next
Header of 41). It MUST use local and peer link-local IPv6 addresses Header of 41). It MUST use local and peer link-local IPv6 addresses
for encapsulation. Manual keying MUST NOT be used, see Section 6.1. for encapsulation. Manual keying MUST NOT be used, see Section 6.2.
Traffic Selectors are: Traffic Selectors are:
TSi = (0, 0-65535, :: - FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF) TSi = (0, 0-65535, :: - FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)
TSr = (0, 0-65535, :: - FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF) TSr = (0, 0-65535, :: - FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)
IPsec tunnel mode is required because the ACP will route/forward IPsec tunnel mode is required because the ACP will route/forward
packets received from any other ACP node across the ACP secure packets received from any other ACP node across the ACP secure
channels, and not only its own generated ACP packets. With IPsec channels, and not only its own generated ACP packets. With IPsec
transport mode (and no additional encapsulation header in the ESP transport mode (and no additional encapsulation header in the ESP
payload), it would only be possible to send packets originated by the payload), it would only be possible to send packets originated by the
ACP node itself because the IPv6 addresses of the ESP must be the ACP node itself because the IPv6 addresses of the ESP must be the
same as that of the outer IPv6 header. same as that of the outer IPv6 header.
6.7.3.1.1. RFC8221 (IPsec/ESP) 6.8.3.1.1. RFC8221 (IPsec/ESP)
ACP IPsec implementations MUST comply with [RFC8221] (and its ACP IPsec implementations MUST comply with [RFC8221] (and its
updates). The requirements from above and this section amend and updates). The requirements from above and this section amend and
superseded its requirements. superseded its requirements.
AH MUST NOT be used (because it does not provide confidentiality). AH MUST NOT be used (because it does not provide confidentiality).
For the required ESP encryption algorithms in section 5 of [RFC8221] For the required ESP encryption algorithms in section 5 of [RFC8221]
the following guidance applies: the following guidance applies:
skipping to change at page 52, line 17 skipping to change at page 53, line 29
effective security backup to AES for the ACP once a policy to effective security backup to AES for the ACP once a policy to
switch over to it or prefer it is available in an ACP framework. switch over to it or prefer it is available in an ACP framework.
[RFC8221] allows for 128-bit or 256-bit AES keys. This document [RFC8221] allows for 128-bit or 256-bit AES keys. This document
mandates that only 256-bit AES keys MUST be supported. mandates that only 256-bit AES keys MUST be supported.
When [RFC8221] is updated, ACP implementations will need to consider When [RFC8221] is updated, ACP implementations will need to consider
legacy interoperability, and the IPsec WG has generally done a very legacy interoperability, and the IPsec WG has generally done a very
good job of taking that into account in its recommendations. good job of taking that into account in its recommendations.
6.7.3.1.2. RFC8247 (IKEv2) 6.8.3.1.2. RFC8247 (IKEv2)
[RFC8247] provides a baseline recommendation for mandatory to [RFC8247] provides a baseline recommendation for mandatory to
implement ciphers, integrity checks, pseudo-random-functions and implement ciphers, integrity checks, pseudo-random-functions and
Diffie-Hellman mechanisms. Those recommendations, and the Diffie-Hellman mechanisms. Those recommendations, and the
recommendations of subsequent documents apply well to the ACP. recommendations of subsequent documents apply well to the ACP.
Because IKEv2 for ACP secure channels is sufficient to be implemented Because IKEv2 for ACP secure channels is sufficient to be implemented
in control plane software, rather than in ASIC hardware, and ACP in control plane software, rather than in ASIC hardware, and ACP
nodes supporting IKEv2 are not assumed to be code-space constrained, nodes supporting IKEv2 are not assumed to be code-space constrained,
and because existing IKEv2 implementations are expected to support and because existing IKEv2 implementations are expected to support
[RFC8247] recommendations, this documents makes no attempt to [RFC8247] recommendations, this documents makes no attempt to
simplify its recommendations for use with the ACP. simplify its recommendations for use with the ACP.
See [IKEV2IANA] for IANA IKEv2 parameter names used in this text. See [IKEV2IANA] for IANA IKEv2 parameter names used in this text.
ACP Nodes supporting IKEv2 MUST comply with [RFC8247] amended by the ACP Nodes supporting IKEv2 MUST comply with [RFC8247] amended by the
following requirements which constitute a policy statement as following requirements which constitute a policy statement as
permitted by [RFC8247]. permitted by [RFC8247].
To signal the ACP certificate chain (including TA) as required by To signal the ACP certificate chain (including TA) as required by
Section 6.7.2, "X.509 Certificate - Signature" payload in IKEv2 can Section 6.8.2, "X.509 Certificate - Signature" payload in IKEv2 can
be used. It is mandatory according to [RFC7296] section 3.6. be used. It is mandatory according to [RFC7296] section 3.6.
ACP nodes SHOULD set up IKEv2 to only use the ACP certificate and TA ACP nodes SHOULD set up IKEv2 to only use the ACP certificate and TA
when acting as an IKEv2 responder on the IPv6 link local address and when acting as an IKEv2 responder on the IPv6 link local address and
port number indicated in the AN_ACP DULL GRASP announcements (see port number indicated in the AN_ACP DULL GRASP announcements (see
Section 6.3). Section 6.4).
When CERTREQ is received from a peer, and does not indicate any of When CERTREQ is received from a peer, and does not indicate any of
this ACP nodes TA certificates, the ACP node SHOULD ignore the this ACP nodes TA certificates, the ACP node SHOULD ignore the
CERTREQ and continue sending its certificate chain including its TA CERTREQ and continue sending its certificate chain including its TA
as subject to the requirements and explanations in Section 6.7.2. as subject to the requirements and explanations in Section 6.8.2.
This will not result in successful mutual authentication but assists This will not result in successful mutual authentication but assists
diagnostics. diagnostics.
Note that with IKEv2, failing authentication will only result in the Note that with IKEv2, failing authentication will only result in the
responder receiving the certificate chain from the initiator, but not responder receiving the certificate chain from the initiator, but not
vice versa. Because ACP secure channel setup is symmetric (see vice versa. Because ACP secure channel setup is symmetric (see
Section 6.6), every non-malicious ACP neighbor will attempt to Section 6.7), every non-malicious ACP neighbor will attempt to
connect as an initiator though, allowing to obtain the diagnostic connect as an initiator though, allowing to obtain the diagnostic
information about the neighbors certificate. information about the neighbors certificate.
In IKEv2, ACP nodes are identified by their ACP address. The In IKEv2, ACP nodes are identified by their ACP address. The
ID_IPv6_ADDR IKEv2 identification payload MUST be used and MUST ID_IPv6_ADDR IKEv2 identification payload MUST be used and MUST
convey the ACP address. If the peer's ACP certificate includes a convey the ACP address. If the peer's ACP certificate includes a
32HEXDIG ACP address in the acp-node-name (not "0" or omitted), the 32HEXDIG ACP address in the acp-node-name (not "0" or omitted), the
address in the IKEv2 identification payload MUST match it. See address in the IKEv2 identification payload MUST match it. See
Section 6.1.3 for more information about "0" or omitted ACP address Section 6.2.3 for more information about "0" or omitted ACP address
fields in the acp-node-name. fields in the acp-node-name.
IKEv2 authentication MUST use authentication method 14 ("Digital IKEv2 authentication MUST use authentication method 14 ("Digital
Signature") for ACP certificates; this authentication method can be Signature") for ACP certificates; this authentication method can be
used with both RSA and ECDSA certificates, indicated by an ASN.1 used with both RSA and ECDSA certificates, indicated by an ASN.1
object AlgorithmIdentifier. object AlgorithmIdentifier.
The Digital Signature hash SHA2-512 MUST be supported (in addition to The Digital Signature hash SHA2-512 MUST be supported (in addition to
SHA2-256). SHA2-256).
The IKEv2 Diffie-Hellman key exchange group 19 (256-bit random ECP), The IKEv2 Diffie-Hellman key exchange group 19 (256-bit random ECP),
listed as a SHOULD, is to be configured, along with the 2048-bit MODP MUST be support. Reason: ECC provides a similar security level to
(group 14). ECC provides a similar security level to finite-field finite-field (MODP) key exchange with a shorter key length, so is
(MODP) key exchange with a shorter key length, so is generally generally preferred absent other considerations.
preferred absent other considerations.
6.7.3.2. IPsec with GRE encapsulation 6.8.3.2. IPsec with GRE encapsulation
In network devices it is often more common to implement high In network devices it is often more common to implement high
performance virtual interfaces on top of GRE encapsulation than on performance virtual interfaces on top of GRE encapsulation than on
top of a "native" IPsec association (without any other encapsulation top of a "native" IPsec association (without any other encapsulation
than those defined by IPsec). On those devices it may be beneficial than those defined by IPsec). On those devices it may be beneficial
to run the ACP secure channel on top of GRE protected by the IPsec to run the ACP secure channel on top of GRE protected by the IPsec
association. association.
The requirements for ESP/IPsec/IKEv2 with GRE are the same as for The requirements for ESP/IPsec/IKEv2 with GRE are the same as for
native IPsec (see Section 6.7.3.1) except that IPsec transport mode native IPsec (see Section 6.8.3.1) except that IPsec transport mode
and next protocol GRE (47) are to be negotiated. Tunnel mode is not and next protocol GRE (47) are to be negotiated. Tunnel mode is not
required because of GRE. Traffic Selectors are: required because of GRE. Traffic Selectors are:
TSi = (47, 0-65535, Initiator-IPv6-LL-addr ... Initiator-ACP-LL-addr) TSi = (47, 0-65535, Initiator-IPv6-LL-addr ... Initiator-ACP-LL-addr)
TSr = (47, 0-65535, Responder-IPv6-LL-addr ... Responder-IPv6-LL- TSr = (47, 0-65535, Responder-IPv6-LL-addr ... Responder-IPv6-LL-
addr) addr)
If IKEv2 initiator and responder support IPsec over GRE, it has to be
preferred over native IPsec. The ACP IPv6 traffic has to be carried
across GRE according to [RFC7676].
6.7.4. ACP via DTLS If IKEv2 initiator and responder support IPsec over GRE, it will be
preferred over native IPsec because of the way how IKEv2 negotiates
transport mode as used by this IPsec over GRE profile) versus tunnel
mode as used by native IPsec (see [RFC7296], section 1.3.1). The ACP
IPv6 traffic has to be carried across GRE according to [RFC7676].
We define the use of ACP via DTLS in the assumption that it is likely 6.8.4. ACP via DTLS
the first transport encryption supported in some classes of
constrained devices because DTLS is already used in those devices but
IPsec is not, and code-space may be limited.
An ACP node announces its ability to support DTLS v1.2 compliant with This document defines the use of ACP via DTLS in the assumption that
the requirements defined in this document as an ACP secure channel it is likely the first transport encryption supported in some classes
protocol in GRASP through the "DTLS" objective-value in the "AN_ACP" of constrained devices because DTLS is already used in those devices
objective. but IPsec is not, and code-space may be limited.
To run ACP via UDP and DTLS [RFC6347], a locally assigned UDP port is An ACP node announces its ability to support DTLS version 1.2
used that is announced as a parameter in the GRASP AN_ACP objective ([RFC6347]) compliant with the requirements defined in this document
to candidate neighbors. This port can also be any newer version of as an ACP secure channel protocol in GRASP through the "DTLS"
DTLS as long as that version can negotiate a DTLS v1.2 connection in objective-value in the "AN_ACP" objective (see Section 6.4).
the presence of an DTLS v1.2 only peer.
To run ACP via UDP and DTLS, a locally assigned UDP port is used that
is announced as a parameter in the GRASP AN_ACP objective to
candidate neighbors. This port can also be any newer version of DTLS
as long as that version can negotiate a DTLS v1.2 connection in the
presence of an DTLS v1.2 only peer.
All ACP nodes supporting DTLS as a secure channel protocol MUST All ACP nodes supporting DTLS as a secure channel protocol MUST
adhere to the DTLS implementation recommendations and security adhere to the DTLS implementation recommendations and security
considerations of BCP 195 [RFC7525] except with respect to the DTLS considerations of BCP 195, BCP 195 [RFC7525] except with respect to
version. ACP nodes supporting DTLS MUST support DTLS 1.2. They MUST the DTLS version. ACP nodes supporting DTLS MUST support DTLS 1.2.
NOT support older versions of DTLS. Implementation MUST comply with They MUST NOT support older versions of DTLS.
BCP 195, [RFC7525].
Unlike for IPsec, no attempts are made to simplify the requirements Unlike for IPsec, no attempts are made to simplify the requirements
of the BCP 195 recommendations because the expectation is that DTLS of the BCP 195 recommendations because the expectation is that DTLS
would be using software-only implementations where the ability to would be using software-only implementations where the ability to
reuse of widely adopted implementations is more important than reuse of widely adopted implementations is more important than
minizing the complexity of a hardware accelerated implementation minizing the complexity of a hardware accelerated implementation
which is known to be important for IPsec. which is known to be important for IPsec.
DTLS v1.3 ([I-D.ietf-tls-dtls13]) is "backward compatible" with DTLS DTLS v1.3 ([I-D.ietf-tls-dtls13]) is "backward compatible" with DTLS
v1.2 (see section 1. of DTLS v1.3): A DTLS implementation supporting v1.2 (see section 1. of DTLS v1.3). A DTLS implementation supporting
both DTLS v1.2 and DTLS v1.3 does comply with the above requirements both DTLS v1.2 and DTLS v1.3 does comply with the above requirements
of negotiating to DTLS v1.2 in the presence of a DTLS v1.2 only peer, of negotiating to DTLS v1.2 in the presence of a DTLS v1.2 only peer,
but using DTLS v1.3 when booth peers support it. but using DTLS v1.3 when booth peers support it.
Version v1.2 is the MTI version of DTLS in this specification because Version v1.2 is the MTI version of DTLS in this specification because
* There is more experience with DTLS v1.2 across the spectrum of * There is more experience with DTLS v1.2 across the spectrum of
target ACP nodes. target ACP nodes.
* Firmware of lower end, embedded ACP nodes may not support a newer * Firmware of lower end, embedded ACP nodes may not support a newer
version for a long time. version for a long time.
skipping to change at page 55, line 40 skipping to change at page 57, line 5
how the text alreayd lays out a non-nrmative desire to support how the text alreayd lays out a non-nrmative desire to support
DTLSv1.3.] DTLSv1.3.]
There is no additional session setup or other security association There is no additional session setup or other security association
besides this simple DTLS setup. As soon as the DTLS session is besides this simple DTLS setup. As soon as the DTLS session is
functional, the ACP peers will exchange ACP IPv6 packets as the functional, the ACP peers will exchange ACP IPv6 packets as the
payload of the DTLS transport connection. Any DTLS defined security payload of the DTLS transport connection. Any DTLS defined security
association mechanisms such as re-keying are used as they would be association mechanisms such as re-keying are used as they would be
for any transport application relying solely on DTLS. for any transport application relying solely on DTLS.
6.7.5. ACP Secure Channel Profiles 6.8.5. ACP Secure Channel Profiles
As explained in the beginning of Section 6.5, there is no single As explained in the beginning of Section 6.6, there is no single
secure channel mechanism mandated for all ACP nodes. Instead, this secure channel mechanism mandated for all ACP nodes. Instead, this
section defines two ACP profiles (baseline and constrained) for ACP section defines two ACP profiles (baseline and constrained) for ACP
nodes that do introduce such requirements. nodes that do introduce such requirements.
A baseline ACP node MUST support IPsec natively and MAY support IPsec An ACP node supporting the "baseline" profile MUST support IPsec
via GRE. If GRE is supported, it MAY be preferred over native IPec. natively and MAY support IPsec via GRE. An ACP node supporting the
A constrained ACP node that cannot support IPsec MUST support DTLS. "constrained" profile node that cannot support IPsec MUST support
An ACP node connecting an area of constrained ACP nodes with an area DTLS. An ACP node connecting an area of constrained ACP nodes with
of baseline ACP nodes needs to support IPsec and DTLS and supports an area of baseline ACP nodes needs to support IPsec and DTLS and
therefore the baseline and constrained profile. supports therefore the baseline and constrained profile.
Explanation: Not all type of ACP nodes can or need to connect Explanation: Not all type of ACP nodes can or need to connect
directly to each other or are able to support or prefer all possible directly to each other or are able to support or prefer all possible
secure channel mechanisms. For example, code space limited IoT secure channel mechanisms. For example, code space limited IoT
devices may only support DTLS because that code exists already on devices may only support DTLS because that code exists already on
them for end-to-end security, but high-end core routers may not want them for end-to-end security, but high-end core routers may not want
to support DTLS because they can perform IPsec in accelerated to support DTLS because they can perform IPsec in accelerated
hardware but would need to support DTLS in an underpowered CPU hardware but would need to support DTLS in an underpowered CPU
forwarding path shared with critical control plane operations. This forwarding path shared with critical control plane operations. This
is not a deployment issue for a single ACP across these type of nodes is not a deployment issue for a single ACP across these type of nodes
skipping to change at page 56, line 31 skipping to change at page 57, line 45
IPsec natively with tunnel mode provides the shortest encapsulation IPsec natively with tunnel mode provides the shortest encapsulation
overhead. GRE may be preferred by legacy implementations because the overhead. GRE may be preferred by legacy implementations because the
virtual interfaces required by ACP design in conjunction with secure virtual interfaces required by ACP design in conjunction with secure
channels have in the past more often been implemented for GRE than channels have in the past more often been implemented for GRE than
purely for native IPsec. purely for native IPsec.
ACP nodes need to specify in documentation the set of secure ACP ACP nodes need to specify in documentation the set of secure ACP
mechanisms they support and should declare which profile they support mechanisms they support and should declare which profile they support
according to above requirements. according to above requirements.
6.8. GRASP in the ACP 6.9. GRASP in the ACP
6.8.1. GRASP as a core service of the ACP 6.9.1. GRASP as a core service of the ACP
The ACP MUST run an instance of GRASP inside of it. It is a key part The ACP MUST run an instance of GRASP inside of it. It is a key part
of the ACP services. The function in GRASP that makes it fundamental of the ACP services. The function in GRASP that makes it fundamental
as a service of the ACP is the ability to provide ACP wide service as a service of the ACP is the ability to provide ACP wide service
discovery (using objectives in GRASP). discovery (using objectives in GRASP).
ACP provides IP unicast routing via the RPL routing protocol (see ACP provides IP unicast routing via the RPL routing protocol (see
Section 6.11). Section 6.12).
The ACP does not use IP multicast routing nor does it provide generic The ACP does not use IP multicast routing nor does it provide generic
IP multicast services (the handling of GRASP link-local multicast IP multicast services (the handling of GRASP link-local multicast
messages is explained in Section 6.8.2). Instead, the ACP provides messages is explained in Section 6.9.2). Instead, the ACP provides
service discovery via the objective discovery/announcement and service discovery via the objective discovery/announcement and
negotiation mechanisms of the ACP GRASP instance (services are a form negotiation mechanisms of the ACP GRASP instance (services are a form
of objectives). These mechanisms use hop-by-hop reliable flooding of of objectives). These mechanisms use hop-by-hop reliable flooding of
GRASP messages for both service discovery (GRASP M_DISCOVERY GRASP messages for both service discovery (GRASP M_DISCOVERY
messages) and service announcement (GRASP M_FLOOD messages). messages) and service announcement (GRASP M_FLOOD messages).
See Appendix A.5 for discussion about this design choice of the ACP. See Appendix A.5 for discussion about this design choice of the ACP.
6.8.2. ACP as the Security and Transport substrate for GRASP 6.9.2. ACP as the Security and Transport substrate for GRASP
In the terminology of GRASP ([I-D.ietf-anima-grasp]), the ACP is the In the terminology of GRASP ([I-D.ietf-anima-grasp]), the ACP is the
security and transport substrate for the GRASP instance run inside security and transport substrate for the GRASP instance run inside
the ACP ("ACP GRASP"). the ACP ("ACP GRASP").
This means that the ACP is responsible for ensuring that this This means that the ACP is responsible for ensuring that this
instance of GRASP is only sending messages across the ACP GRASP instance of GRASP is only sending messages across the ACP GRASP
virtual interfaces. Whenever the ACP adds or deletes such an virtual interfaces. Whenever the ACP adds or deletes such an
interface because of new ACP secure channels or loss thereof, the ACP interface because of new ACP secure channels or loss thereof, the ACP
needs to indicate this to the ACP instance of GRASP. The ACP exists needs to indicate this to the ACP instance of GRASP. The ACP exists
skipping to change at page 57, line 33 skipping to change at page 58, line 47
MUST still be able to operate, and MUST be able to understand that MUST still be able to operate, and MUST be able to understand that
there is no ACP and that therefore the ACP instance of GRASP cannot there is no ACP and that therefore the ACP instance of GRASP cannot
operate. operate.
The following explanation how ACP acts as the security and transport The following explanation how ACP acts as the security and transport
substrate for GRASP is visualized in Figure 9 below. substrate for GRASP is visualized in Figure 9 below.
GRASP unicast messages inside the ACP always use the ACP address. GRASP unicast messages inside the ACP always use the ACP address.
Link-local addresses from the ACP VRF MUST NOT be used inside Link-local addresses from the ACP VRF MUST NOT be used inside
objectives. GRASP unicast messages inside the ACP are transported objectives. GRASP unicast messages inside the ACP are transported
via TLS which MUST comply with [RFC7525] execept that only TLS 1.2 via TLS. See Section 6.1 for TLS requirements. TLS mutual
([RFC5246]) is REQUIRED and TLS 1.3 ([RFC8446] is RECOMMENDED. There authentication MUST use the ACP domain membership check defined in
is no need for older version backward compatibility in the new use- (Section 6.2.3).
case of ACP. Mutual authentication MUST use the ACP domain
membership check defined in (Section 6.1.3).
GRASP link-local multicast messages are targeted for a specific ACP GRASP link-local multicast messages are targeted for a specific ACP
virtual interface (as defined Section 6.12.5) but are sent by the ACP virtual interface (as defined Section 6.13.5) but are sent by the ACP
into an ACP GRASP virtual interface that is constructed from the TCP into an ACP GRASP virtual interface that is constructed from the TCP
connection(s) to the IPv6 link-local neighbor address(es) on the connection(s) to the IPv6 link-local neighbor address(es) on the
underlying ACP virtual interface. If the ACP GRASP virtual interface underlying ACP virtual interface. If the ACP GRASP virtual interface
has two or more neighbors, the GRASP link-local multicast messages has two or more neighbors, the GRASP link-local multicast messages
are replicated to all neighbor TCP connections. are replicated to all neighbor TCP connections.
TLS for GRASP MUST offer TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 and
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 and MUST NOT offer options
with less than 256 bit symmetric key strength or hash strength of
less than SHA384. When TLS 1.3 is supported, TLS_AES_256_GCM_SHA384
MUST be offered and TLS_CHACHA20_POLY1305_SHA256 MAY be offered. TLS
for GRASP MUST also include the "Supported Elliptic Curves"
extension, it MUST support support the NIST P-256 (secp256r1) and
P-384 (secp384r1(24)) curves [RFC4492]. In addition, GRASP TLS
clients SHOULD send an ec_point_formats extension with a single
element, "uncompressed". For further interoperability
recommendations, GRASP TLS implementations SHOULD follow [RFC7525].
TCP and TLS connections for GRASP in the ACP use the IANA assigned TCP and TLS connections for GRASP in the ACP use the IANA assigned
TCP port for GRASP (7107). Effectively the transport stack is TCP port for GRASP (7107). Effectively the transport stack is
expected to be TLS for connections from/to the ACP address (e.g., expected to be TLS for connections from/to the ACP address (e.g.,
global scope address(es)) and TCP for connections from/to link-local global scope address(es)) and TCP for connections from/to link-local
addresses on the ACP virtual interfaces. The latter ones are only addresses on the ACP virtual interfaces. The latter ones are only
used for flooding of GRASP messages. used for flooding of GRASP messages.
..............................ACP.............................. ..............................ACP..............................
. . . .
. /-GRASP-flooding-\ ACP GRASP instance . . /-GRASP-flooding-\ ACP GRASP instance .
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| | Data-Plane | | Data-Plane
| | | |
| | - ACP secure channel | | - ACP secure channel
link-local link-local - encapsulation addresses link-local link-local - encapsulation addresses
subnet1 subnet2 - Data-Plane interfaces subnet1 subnet2 - Data-Plane interfaces
| | | |
ACP-Nbr1 ACP-Nbr2 ACP-Nbr1 ACP-Nbr2
Figure 9: ACP as security and transport substrate for GRASP Figure 9: ACP as security and transport substrate for GRASP
6.8.2.1. Discussion 6.9.2.1. Discussion
TCP encapsulation for GRASP M_DISCOVERY and M_FLOOD link local TCP encapsulation for GRASP M_DISCOVERY and M_FLOOD link local
messages is used because these messages are flooded across messages is used because these messages are flooded across
potentially many hops to all ACP nodes and a single link with even potentially many hops to all ACP nodes and a single link with even
temporary packet loss issues (e.g., WiFi/Powerline link) can reduce temporary packet loss issues (e.g., WiFi/Powerline link) can reduce
the probability for loss free transmission so much that applications the probability for loss free transmission so much that applications
would want to increase the frequency with which they send these would want to increase the frequency with which they send these
messages. Such shorter periodic retransmission of datagrams would messages. Such shorter periodic retransmission of datagrams would
result in more traffic and processing overhead in the ACP than the result in more traffic and processing overhead in the ACP than the
hop-by-hop reliable retransmission mechanism by TCP and duplicate hop-by-hop reliable retransmission mechanism by TCP and duplicate
skipping to change at page 61, line 10 skipping to change at page 62, line 10
* Secure channel methods such as IPsec may provide protection * Secure channel methods such as IPsec may provide protection
against additional attacks, for example reset-attacks. against additional attacks, for example reset-attacks.
* The secure channel method may leverage hardware acceleration and * The secure channel method may leverage hardware acceleration and
there may be little or no gain in eliminating it. there may be little or no gain in eliminating it.
* There is no different security model for ACP GRASP from other ACP * There is no different security model for ACP GRASP from other ACP
traffic. Instead, there is just another layer of protection traffic. Instead, there is just another layer of protection
against certain attacks from the inside which is important due to against certain attacks from the inside which is important due to
the role of GRASP in the ACP. the role of GRASP in the ACP.
6.9. Context Separation 6.10. Context Separation
The ACP is in a separate context from the normal Data-Plane of the The ACP is in a separate context from the normal Data-Plane of the
node. This context includes the ACP channels' IPv6 forwarding and node. This context includes the ACP channels' IPv6 forwarding and
routing as well as any required higher layer ACP functions. routing as well as any required higher layer ACP functions.
In classical network system, a dedicated VRF is one logical In classical network system, a dedicated VRF is one logical
implementation option for the ACP. If possible by the systems implementation option for the ACP. If possible by the systems
software architecture, separation options that minimize shared software architecture, separation options that minimize shared
components are preferred, such as a logical container or virtual components are preferred, such as a logical container or virtual
machine instance. The context for the ACP needs to be established machine instance. The context for the ACP needs to be established
automatically during bootstrap of a node. As much as possible it automatically during bootstrap of a node. As much as possible it
should be protected from being modified unintentionally by ("Data- should be protected from being modified unintentionally by ("Data-
Plane") configuration. Plane") configuration.
Context separation improves security, because the ACP is not Context separation improves security, because the ACP is not
reachable from the Data-Plane routing or forwarding table(s). Also, reachable from the Data-Plane routing or forwarding table(s). Also,
configuration errors from the Data-Plane setup do not affect the ACP. configuration errors from the Data-Plane setup do not affect the ACP.
6.10. Addressing inside the ACP 6.11. Addressing inside the ACP
The channels explained above typically only establish communication The channels explained above typically only establish communication
between two adjacent nodes. In order for communication to happen between two adjacent nodes. In order for communication to happen
across multiple hops, the autonomic control plane requires ACP across multiple hops, the autonomic control plane requires ACP
network wide valid addresses and routing. Each ACP node creates a network wide valid addresses and routing. Each ACP node creates a
Loopback interface with an ACP network wide unique address (prefix) Loopback interface with an ACP network wide unique address (prefix)
inside the ACP context (as explained in in Section 6.9). This inside the ACP context (as explained in in Section 6.10). This
address may be used also in other virtual contexts. address may be used also in other virtual contexts.
With the algorithm introduced here, all ACP nodes in the same routing With the algorithm introduced here, all ACP nodes in the same routing
subdomain have the same /48 ULA prefix. Conversely, ULA global IDs subdomain have the same /48 ULA prefix. Conversely, ULA global IDs
from different domains are unlikely to clash, such that two ACP from different domains are unlikely to clash, such that two ACP
networks can be merged, as long as the policy allows that merge. See networks can be merged, as long as the policy allows that merge. See
also Section 10.1 for a discussion on merging domains. also Section 10.1 for a discussion on merging domains.
Links inside the ACP only use link-local IPv6 addressing, such that Links inside the ACP only use link-local IPv6 addressing, such that
each node's ACP only requires one routable address prefix. each node's ACP only requires one routable address prefix.
6.10.1. Fundamental Concepts of Autonomic Addressing 6.11.1. Fundamental Concepts of Autonomic Addressing
* Usage: Autonomic addresses are exclusively used for self- * Usage: Autonomic addresses are exclusively used for self-
management functions inside a trusted domain. They are not used management functions inside a trusted domain. They are not used
for user traffic. Communications with entities outside the for user traffic. Communications with entities outside the
trusted domain use another address space, for example normally trusted domain use another address space, for example normally
managed routable address space (called "Data-Plane" in this managed routable address space (called "Data-Plane" in this
document). document).
* Separation: Autonomic address space is used separately from user * Separation: Autonomic address space is used separately from user
address space and other address realms. This supports the address space and other address realms. This supports the
robustness requirement. robustness requirement.
* Loopback-only: Only ACP Loopback interfaces (and potentially those * Loopback-only: Only ACP Loopback interfaces (and potentially those
configured for "ACP connect", see Section 8.1) carry routable configured for "ACP connect", see Section 8.1) carry routable
address(es); all other interfaces (called ACP virtual interfaces) address(es); all other interfaces (called ACP virtual interfaces)
only use IPv6 link local addresses. The usage of IPv6 link local only use IPv6 link local addresses. The usage of IPv6 link local
addressing is discussed in [RFC7404]. addressing is discussed in [RFC7404].
* Use-ULA: For Loopback interfaces of ACP nodes, we use ULA with L=1 * Use-ULA: For Loopback interfaces of ACP nodes, we use ULA with L=1
(as defined in section 3.1 of [RFC4193]). Note that the random (as defined in section 3.1 of [RFC4193]). Note that the random
hash for ACP Loopback addresses uses the definition in hash for ACP Loopback addresses uses the definition in
Section 6.10.2 and not the one of [RFC4193] section 3.2.2. Section 6.11.2 and not the one of [RFC4193] section 3.2.2.
* No external connectivity: They do not provide access to the * No external connectivity: They do not provide access to the
Internet. If a node requires further reaching connectivity, it Internet. If a node requires further reaching connectivity, it
should use another, traditionally managed address scheme in should use another, traditionally managed address scheme in
parallel. parallel.
* Addresses in the ACP are permanent, and do not support temporary * Addresses in the ACP are permanent, and do not support temporary
addresses as defined in [RFC4941]. addresses as defined in [RFC4941].
* Addresses in the ACP are not considered sensitive on privacy * Addresses in the ACP are not considered sensitive on privacy
grounds because ACP nodes are not expected to be end-user host. grounds because ACP nodes are not expected to be end-user hosts
All ACP nodes are in one (potentially federated) administrative and ACP addresses do therefore not represent end-users or groups
domain. They are assumed to be to be candidate hosts of ACP of end-users. All ACP nodes are in one (potentially federated)
traffic amongst each other or transit thereof. There are no administrative domain. They are assumed to be to be candidate
transit nodes less privileged to know about the identity of other hosts of ACP traffic amongst each other or transit thereof. There
hosts in the ACP. Therefore, ACP addresses do not need to be are no transit nodes less privileged to know about the identity of
pseudo-random as discussed in [RFC7721]. Because they are not other hosts in the ACP. Therefore, ACP addresses do not need to
be pseudo-random as discussed in [RFC7721]. Because they are not
propagated to untrusted (non ACP) nodes and stay within a domain propagated to untrusted (non ACP) nodes and stay within a domain
(of trust), we also consider them not to be subject to scanning (of trust), we also consider them not to be subject to scanning
attacks. attacks.
The ACP is based exclusively on IPv6 addressing, for a variety of The ACP is based exclusively on IPv6 addressing, for a variety of
reasons: reasons:
* Simplicity, reliability and scale: If other network layer * Simplicity, reliability and scale: If other network layer
protocols were supported, each would have to have its own set of protocols were supported, each would have to have its own set of
security associations, routing table and process, etc. security associations, routing table and process, etc.
skipping to change at page 63, line 7 skipping to change at page 64, line 7
autonomic service agents are new concepts. They can be autonomic service agents are new concepts. They can be
exclusively built on IPv6 from day one. There is no need for exclusively built on IPv6 from day one. There is no need for
backward compatibility. backward compatibility.
* OAM protocols do not require IPv4: The ACP may carry OAM * OAM protocols do not require IPv4: The ACP may carry OAM
protocols. All relevant protocols (SNMP, TFTP, SSH, SCP, Radius, protocols. All relevant protocols (SNMP, TFTP, SSH, SCP, Radius,
Diameter, ...) are available in IPv6. See also [RFC8368] for how Diameter, ...) are available in IPv6. See also [RFC8368] for how
ACP could be made to interoperate with IPv4 only OAM. ACP could be made to interoperate with IPv4 only OAM.
Further explanation about the addressing and routing related reasons Further explanation about the addressing and routing related reasons
for the choice of the autonomous ACP addressing can be found in for the choice of the autonomous ACP addressing can be found in
Section 6.12.5.1. Section 6.13.5.1.
6.10.2. The ACP Addressing Base Scheme 6.11.2. The ACP Addressing Base Scheme
The Base ULA addressing scheme for ACP nodes has the following The Base ULA addressing scheme for ACP nodes has the following
format: format:
8 40 2 78 8 40 2 78
+--+-------------------------+------+------------------------------+ +--+-------------------------+------+------------------------------+
|fd| hash(routing-subdomain) | Type | (sub-scheme) | |fd| hash(routing-subdomain) | Type | (sub-scheme) |
+--+-------------------------+------+------------------------------+ +--+-------------------------+------+------------------------------+
Figure 10: ACP Addressing Base Scheme Figure 10: ACP Addressing Base Scheme
The first 48-bits follow the ULA scheme, as defined in [RFC4193], to The first 48-bits follow the ULA scheme, as defined in [RFC4193], to
which a type field is added: which a type field is added:
* "fd" identifies a locally defined ULA address. * "fd" identifies a locally defined ULA address.
* The 40-bits ULA "global ID" (term from [RFC4193]) for ACP * The 40-bits ULA "global ID" (term from [RFC4193]) for ACP
addresses carried in the acp-node-name in the ACP certificates are addresses carried in the acp-node-name in the ACP certificates are
the first 40-bits of the SHA256 hash of the routing subdomain from the first 40-bits of the SHA256 hash of the routing subdomain from
the same acp-node-name. In the example of Section 6.1.2, the the same acp-node-name. In the example of Section 6.2.2, the
routing subdomain is "area51.research.acp.example.com" and the routing subdomain is "area51.research.acp.example.com" and the
40-bits ULA "global ID" 89b714f3db. 40-bits ULA "global ID" 89b714f3db.
* When creating a new routing-subdomain for an existing autonomic * When creating a new routing-subdomain for an existing autonomic
network, it MUST be ensured, that rsub is selected so the network, it MUST be ensured, that rsub is selected so the
resulting hash of the routing-subdomain does not collide with the resulting hash of the routing-subdomain does not collide with the
hash of any pre-existing routing-subdomains of the autonomic hash of any pre-existing routing-subdomains of the autonomic
network. This ensures that ACP addresses created by registrars network. This ensures that ACP addresses created by registrars
for different routing subdomains do not collide with each others. for different routing subdomains do not collide with each others.
* To allow for extensibility, the fact that the ULA "global ID" is a * To allow for extensibility, the fact that the ULA "global ID" is a
hash of the routing subdomain SHOULD NOT be assumed by any ACP hash of the routing subdomain SHOULD NOT be assumed by any ACP
skipping to change at page 64, line 23 skipping to change at page 65, line 23
open. When taking this future possibility into account, it is open. When taking this future possibility into account, it is
easy to always select rsub so that no collisions happen. easy to always select rsub so that no collisions happen.
* Type: This field allows different address sub-schemes. This * Type: This field allows different address sub-schemes. This
addresses the "upgradability" requirement. Assignment of types addresses the "upgradability" requirement. Assignment of types
for this field will be maintained by IANA. for this field will be maintained by IANA.
The sub-scheme may imply a range or set of addresses assigned to the The sub-scheme may imply a range or set of addresses assigned to the
node, this is called the ACP address range/set and explained in each node, this is called the ACP address range/set and explained in each
sub-scheme. sub-scheme.
Please refer to Section 6.10.7 and Appendix A.1 for further Please refer to Section 6.11.7 and Appendix A.1 for further
explanations why the following Sub-Addressing schemes are used and explanations why the following Sub-Addressing schemes are used and
why multiple are necessary. why multiple are necessary.
The following summarizes the addressing Sub-Schemes: The following summarizes the addressing Sub-Schemes:
+------+-----+-----------------+-------+------------+ +------+-----+-----------------+-------+------------+
| Type | Z | name | F-bit | V-bit size | | Type | Z | name | F-bit | V-bit size |
+------+-----+-----------------+-------+------------+ +------+-----+-----------------+-------+------------+
| 0x00 | 0 | ACP-Zone | N/A | 1 bit | | 0x00 | 0 | ACP-Zone | N/A | 1 bit |
+------+-----+-----------------+-------+------------+ +------+-----+-----------------+-------+------------+
| 0x00 | 1 | ACP-Manual | N/A | 1 bit | | 0x00 | 1 | ACP-Manual | N/A | 1 bit |
+------+-----+-----------------+-------+------------+ +------+-----+-----------------+-------+------------+
| 0x01 | N/A | ACP-VLong-8 | 0 | 8 bits | | 0x01 | N/A | ACP-VLong-8 | 0 | 8 bits |
+------+-----+-----------------+-------+------------+ +------+-----+-----------------+-------+------------+
| 0x01 | N/A | ACP-VLong-16 | 1 | 16 bits | | 0x01 | N/A | ACP-VLong-16 | 1 | 16 bits |
+------+-----+-----------------+-------+------------+ +------+-----+-----------------+-------+------------+
Figure 11: Addressing schemes Figure 11: Addressing schemes
6.10.3. ACP Zone Addressing Sub-Scheme (ACP-Zone) 6.11.3. ACP Zone Addressing Sub-Scheme (ACP-Zone)
This sub-scheme is used when the Type field of the base scheme is This sub-scheme is used when the Type field of the base scheme is
0x00 and the Z bit is 0x0. 0x00 and the Z bit is 0x0.
64 64 64 64
+-----------------+---+---------++-----------------------------+---+ +-----------------+---+---------++-----------------------------+---+
| (base scheme) | Z | Zone-ID || Node-ID | | (base scheme) | Z | Zone-ID || Node-ID |
| | | || Registrar-ID | Node-Number| V | | | | || Registrar-ID | Node-Number| V |
+-----------------+---+---------++--------------+--------------+---+ +-----------------+---+---------++--------------+--------------+---+
50 1 13 48 15 1 50 1 13 48 15 1
skipping to change at page 65, line 27 skipping to change at page 66, line 27
* Z: MUST be 0x0. * Z: MUST be 0x0.
* Zone-ID: A value for a network zone. * Zone-ID: A value for a network zone.
* Node-ID: A unique value for each node. * Node-ID: A unique value for each node.
The 64-bit Node-ID must be unique across the ACP domain for each The 64-bit Node-ID must be unique across the ACP domain for each
node. It is derived and composed as follows: node. It is derived and composed as follows:
* Registrar-ID (48-bit): A number unique inside the domain that * Registrar-ID (48-bit): A number unique inside the domain that
identifies the ACP registrar which assigned the Node-ID to the identifies the ACP registrar which assigned the Node-ID to the
node. One or more domain-wide unique identifiers of the ACP node. One or more domain-wide unique identifiers of the ACP
registrar can be used for this purpose. See Section 6.10.7.2. registrar can be used for this purpose. See Section 6.11.7.2.
* Node-Number: Number to make the Node-ID unique. This can be * Node-Number: Number to make the Node-ID unique. This can be
sequentially assigned by the ACP Registrar owning the Registrar- sequentially assigned by the ACP Registrar owning the Registrar-
ID. ID.
* V (1-bit): Virtualization bit: 0: Indicates the ACP itself ("ACP * V (1-bit): Virtualization bit: 0: Indicates the ACP itself ("ACP
node base system); 1: Indicates the optional "host" context on the node base system); 1: Indicates the optional "host" context on the
ACP node (see below). ACP node (see below).
In the ACP Zone Addressing Sub-Scheme, the ACP address in the In the ACP Zone Addressing Sub-Scheme, the ACP address in the
certificate has V field as all zero bits. certificate has V field as all zero bits.
skipping to change at page 66, line 21 skipping to change at page 67, line 21
be used in conjunction with operational practices for partial/ be used in conjunction with operational practices for partial/
incremental adoption of the ACP as described in Section 9.4. incremental adoption of the ACP as described in Section 9.4.
Note: Zones and Zone-ID as defined here are not related to [RFC4007] Note: Zones and Zone-ID as defined here are not related to [RFC4007]
zones or zone_id. ACP zone addresses are not scoped (reachable only zones or zone_id. ACP zone addresses are not scoped (reachable only
from within an RFC4007 zone) but reachable across the whole ACP. An from within an RFC4007 zone) but reachable across the whole ACP. An
RFC4007 zone_id is a zone index that has only local significance on a RFC4007 zone_id is a zone index that has only local significance on a
node, whereas an ACP Zone-ID is an identifier for an ACP zone that is node, whereas an ACP Zone-ID is an identifier for an ACP zone that is
unique across that ACP. unique across that ACP.
6.10.4. ACP Manual Addressing Sub-Scheme (ACP-Manual) 6.11.4. ACP Manual Addressing Sub-Scheme (ACP-Manual)
This sub-scheme is used when the Type field of the base scheme is This sub-scheme is used when the Type field of the base scheme is
0x00 and the Z bit is 0x1. 0x00 and the Z bit is 0x1.
64 64 64 64
+---------------------+---+----------++-----------------------------+ +---------------------+---+----------++-----------------------------+
| (base scheme) | Z | Subnet-ID|| Interface Identifier | | (base scheme) | Z | Subnet-ID|| Interface Identifier |
+---------------------+---+----------++-----------------------------+ +---------------------+---+----------++-----------------------------+
50 1 13 50 1 13
skipping to change at page 67, line 26 skipping to change at page 68, line 26
connect interfaces of ACP edge nodes (see Section 8.1), without connect interfaces of ACP edge nodes (see Section 8.1), without
setting up an ACP secure channel. Their ACP certificate MUST omit setting up an ACP secure channel. Their ACP certificate MUST omit
the acp-address field to indicate that their ACP certificate is only the acp-address field to indicate that their ACP certificate is only
usable for non- ACP secure channel authentication, such as end-to-end usable for non- ACP secure channel authentication, such as end-to-end
transport connections across the ACP or Data-Plane. transport connections across the ACP or Data-Plane.
Address management of ACP connect subnets is done using traditional Address management of ACP connect subnets is done using traditional
assignment methods and existing IPv6 protocols. See Section 8.1.3 assignment methods and existing IPv6 protocols. See Section 8.1.3
for details. for details.
6.10.5. ACP Vlong Addressing Sub-Scheme (ACP-VLong-8/ACP-VLong-16 6.11.5. ACP Vlong Addressing Sub-Scheme (ACP-VLong-8/ACP-VLong-16
This sub-scheme is used when the Type field of the base scheme is This sub-scheme is used when the Type field of the base scheme is
0x01. 0x01.
50 78 50 78
+---------------------++-----------------------------+----------+ +---------------------++-----------------------------+----------+
| (base scheme) || Node-ID | | (base scheme) || Node-ID |
| || Registrar-ID |F| Node-Number| V | | || Registrar-ID |F| Node-Number| V |
+---------------------++--------------+--------------+----------+ +---------------------++--------------+--------------+----------+
50 46 1 23/15 8/16 50 46 1 23/15 8/16
skipping to change at page 68, line 8 skipping to change at page 69, line 8
The fields are the same as in the Zone-ID sub-scheme with the The fields are the same as in the Zone-ID sub-scheme with the
following refinements: following refinements:
* F: format bit. This bit determines the format of the subsequent * F: format bit. This bit determines the format of the subsequent
bits. bits.
* V: Virtualization bit: this is a field that is either 8 or 16 * V: Virtualization bit: this is a field that is either 8 or 16
bits. For F=0, it is 8 bits, for F=1 it is 16 bits. The V bits bits. For F=0, it is 8 bits, for F=1 it is 16 bits. The V bits
are assigned by the ACP node. In the ACP certificate's ACP are assigned by the ACP node. In the ACP certificate's ACP
address Section 6.1.2, the V-bits are always set to 0. address Section 6.2.2, the V-bits are always set to 0.
* Registrar-ID: To maximize Node-Number and V, the Registrar-ID is * Registrar-ID: To maximize Node-Number and V, the Registrar-ID is
reduced to 46-bits. One or more domain-wide unique identifiers of reduced to 46-bits. One or more domain-wide unique identifiers of
the ACP registrar can be used for this purpose. See the ACP registrar can be used for this purpose. See
Section 6.10.7.2. Section 6.11.7.2.
* The Node-Number is unique to each ACP node. There are two formats * The Node-Number is unique to each ACP node. There are two formats
for the Node-Number. When F=0, the node-number is 23 bits, for for the Node-Number. When F=0, the node-number is 23 bits, for
F=1 it is 15 bits. Each format of node-number is considered to be F=1 it is 15 bits. Each format of node-number is considered to be
in a unique number space. in a unique number space.
The F=0 bit format addresses are intended to be used for "general The F=0 bit format addresses are intended to be used for "general
purpose" ACP nodes that would potentially have a limited number (< purpose" ACP nodes that would potentially have a limited number (<
256) of clients (ASA/Autonomic Functions or legacy services) of the 256) of clients (ASA/Autonomic Functions or legacy services) of the
ACP that require separate V(irtual) addresses. ACP that require separate V(irtual) addresses.
The F=1 bit Node-Numbers are intended for ACP nodes that are ACP edge The F=1 bit Node-Numbers are intended for ACP nodes that are ACP edge
nodes (see Section 8.1.1) or that have a large number of clients nodes (see Section 8.1.1) or that have a large number of clients
requiring separate V(irtual) addresses. For example large SDN requiring separate V(irtual) addresses. For example large SDN
controllers with container modular software architecture (see controllers with container modular software architecture (see
Section 8.1.2). Section 8.1.2).
In the Vlong addressing sub-scheme, the ACP address in the In the Vlong addressing sub-scheme, the ACP address in the
certificate has all V field bits as zero. The ACP address set for certificate has all V field bits as zero. The ACP address set for
the node includes any V value. the node includes any V value.
6.10.6. Other ACP Addressing Sub-Schemes 6.11.6. Other ACP Addressing Sub-Schemes
Before further addressing sub-schemes are defined, experience with Before further addressing sub-schemes are defined, experience with
the schemes defined here should be collected. The schemes defined in the schemes defined here should be collected. The schemes defined in
this document have been devised to allow hopefully sufficiently this document have been devised to allow hopefully sufficiently
flexible setup of ACPs for a variety of situation. These reasons flexible setup of ACPs for a variety of situation. These reasons
also lead to the fairly liberal use of address space: The Zone also lead to the fairly liberal use of address space: The Zone
Addressing Sub-Scheme is intended to enable optimized routing in Addressing Sub-Scheme is intended to enable optimized routing in
large networks by reserving bits for Zone-ID's. The Vlong addressing large networks by reserving bits for Zone-ID's. The Vlong addressing
sub-scheme enables the allocation of 8/16-bit of addresses inside sub-scheme enables the allocation of 8/16-bit of addresses inside
individual ACP nodes. Both address spaces allow distributed, individual ACP nodes. Both address spaces allow distributed,
uncoordinated allocation of node addresses by reserving bits for the uncoordinated allocation of node addresses by reserving bits for the
registrar-ID field in the address. registrar-ID field in the address.
IANA is asked need to assign a new "type" for each new addressing 6.11.7. ACP Registrars
sub-scheme. With the current allocations, only 2 more schemes are
possible, so the last addressing scheme MUST provide further
extensions (e.g., by reserving bits from it for further extensions).
6.10.7. ACP Registrars
ACP registrars are responsible to enroll candidate ACP nodes with ACP ACP registrars are responsible to enroll candidate ACP nodes with ACP
certificates and associated trust anchor(s). They are also certificates and associated trust anchor(s). They are also
responsible that an acp-node-name field is included in the ACP responsible that an acp-node-name field is included in the ACP
certificate carrying the ACP domain name and the ACP nodes ACP certificate carrying the ACP domain name and the ACP nodes ACP
address prefix. This address prefix is intended to persist unchanged address prefix. This address prefix is intended to persist unchanged
through the lifetime of the ACP node. through the lifetime of the ACP node.
Because of the ACP addressing sub-schemes, an ACP domain can have Because of the ACP addressing sub-schemes, an ACP domain can have
multiple distributed ACP registrars that do not need to coordinate multiple distributed ACP registrars that do not need to coordinate
skipping to change at page 69, line 31 skipping to change at page 70, line 31
ACP registrars are PKI registration authorities (RA) enhanced with ACP registrars are PKI registration authorities (RA) enhanced with
the handling of the ACP certificate specific fields. They request the handling of the ACP certificate specific fields. They request
certificates for ACP nodes from a Certification Authority through any certificates for ACP nodes from a Certification Authority through any
appropriate mechanism (out of scope in this document, but required to appropriate mechanism (out of scope in this document, but required to
be BRSKI for ANI registrars). Only nodes that are trusted to be be BRSKI for ANI registrars). Only nodes that are trusted to be
compliant with the requirements against registrar described in this compliant with the requirements against registrar described in this
section can be given the necessary credentials to perform this RA section can be given the necessary credentials to perform this RA
function, such as credentials for the BRSKI connection to the CA for function, such as credentials for the BRSKI connection to the CA for
ANI registrars. ANI registrars.
6.10.7.1. Use of BRSKI or other Mechanism/Protocols 6.11.7.1. Use of BRSKI or other Mechanism/Protocols
Any protocols or mechanisms may be used by ACP registrars, as long as Any protocols or mechanisms may be used by ACP registrars, as long as
the resulting ACP certificate and TA certificate(s) allow to perform the resulting ACP certificate and TA certificate(s) allow to perform
the ACP domain membership described in Section 6.1.3 with other ACP the ACP domain membership described in Section 6.2.3 with other ACP
domain members, and meet the ACP addressing requirements for its acp- domain members, and meet the ACP addressing requirements for its acp-
node-name as described further below in this section. node-name as described further below in this section.
An ACP registrar could be a person deciding whether to enroll a An ACP registrar could be a person deciding whether to enroll a
candidate ACP node and then orchestrating the enrollment of the ACP candidate ACP node and then orchestrating the enrollment of the ACP
certificate and associated TA, using command line or web based certificate and associated TA, using command line or web based
commands on the candidate ACP node and TA to generate and sign the commands on the candidate ACP node and TA to generate and sign the
ACP certificate and configure certificate and TA onto the node. ACP certificate and configure certificate and TA onto the node.
The only currently defined protocol for ACP registrars is BRSKI The only currently defined protocol for ACP registrars is BRSKI
([I-D.ietf-anima-bootstrapping-keyinfra]). When BRSKI is used, the ([I-D.ietf-anima-bootstrapping-keyinfra]). When BRSKI is used, the
ACP nodes are called ANI nodes, and the ACP registrars are called ACP nodes are called ANI nodes, and the ACP registrars are called
BRSKI or ANI registrars. The BRSKI specification does not define the BRSKI or ANI registrars. The BRSKI specification does not define the
handling of the acp-node-name field because the rules do not depend handling of the acp-node-name field because the rules do not depend
on BRSKI but apply equally to any protocols/mechanisms an ACP on BRSKI but apply equally to any protocols/mechanisms an ACP
registrar may use. registrar may use.
6.10.7.2. Unique Address/Prefix allocation 6.11.7.2. Unique Address/Prefix allocation
ACP registrars MUST NOT allocate ACP address prefixes to ACP nodes ACP registrars MUST NOT allocate ACP address prefixes to ACP nodes
via the acp-node-name that would collide with the ACP address via the acp-node-name that would collide with the ACP address
prefixes of other ACP nodes in the same ACP domain. This includes prefixes of other ACP nodes in the same ACP domain. This includes
both prefixes allocated by the same ACP registrar to different ACP both prefixes allocated by the same ACP registrar to different ACP
nodes as well as prefixes allocated by other ACP registrars for the nodes as well as prefixes allocated by other ACP registrars for the
same ACP domain. same ACP domain.
To support such unique address allocation, an ACP registrar MUST have To support such unique address allocation, an ACP registrar MUST have
one or more 46-bit identifiers unique across the ACP domain which is one or more 46-bit identifiers unique across the ACP domain which is
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centrally administered, lightweight ACP registrar implementations. centrally administered, lightweight ACP registrar implementations.
There is no mechanism to deduce from a MAC address itself whether it There is no mechanism to deduce from a MAC address itself whether it
is actually uniquely assigned. Implementations need to consult is actually uniquely assigned. Implementations need to consult
additional offline information before making this assumption. For additional offline information before making this assumption. For
example by knowing that a particular physical product/MIC-chip is example by knowing that a particular physical product/MIC-chip is
guaranteed to use globally unique assigned EUI-48 MAC address(es). guaranteed to use globally unique assigned EUI-48 MAC address(es).
When the candidate ACP device (called Pledge in BRSKI) is to be When the candidate ACP device (called Pledge in BRSKI) is to be
enrolled into an ACP domain, the ACP registrar needs to allocate a enrolled into an ACP domain, the ACP registrar needs to allocate a
unique ACP address to the node and ensure that the ACP certificate unique ACP address to the node and ensure that the ACP certificate
gets a acp-node-name field (Section 6.1.2) with the appropriate gets a acp-node-name field (Section 6.2.2) with the appropriate
information - ACP domain-name, ACP-address, and so on. If the ACP information - ACP domain-name, ACP-address, and so on. If the ACP
registrar uses BRSKI, it signals the ACP acp-node-name field to the registrar uses BRSKI, it signals the ACP acp-node-name field to the
Pledge via the EST /csrattrs command (see Pledge via the EST /csrattrs command (see
[I-D.ietf-anima-bootstrapping-keyinfra], section 5.9.2 - "EST CSR [I-D.ietf-anima-bootstrapping-keyinfra], section 5.9.2 - "EST CSR
Attributes"). Attributes").
[RFC Editor: please update reference to section 5.9.2 accordingly [RFC Editor: please update reference to section 5.9.2 accordingly
with latest BRSKI draft at time of publishing, or RFC] with latest BRSKI draft at time of publishing, or RFC]
6.10.7.3. Addressing Sub-Scheme Policies 6.11.7.3. Addressing Sub-Scheme Policies
The ACP registrar selects for the candidate ACP node a unique address The ACP registrar selects for the candidate ACP node a unique address
prefix from an appropriate ACP addressing sub-scheme, either a zone prefix from an appropriate ACP addressing sub-scheme, either a zone
addressing sub-scheme prefix (see Section 6.10.3), or a Vlong addressing sub-scheme prefix (see Section 6.11.3), or a Vlong
addressing sub-scheme prefix (see Section 6.10.5). The assigned ACP addressing sub-scheme prefix (see Section 6.11.5). The assigned ACP
address prefix encoded in the acp-node-name field of the ACP address prefix encoded in the acp-node-name field of the ACP
certificate indicates to the ACP node its ACP address information. certificate indicates to the ACP node its ACP address information.
The sub-addressing scheme indicates the prefix length: /127 for zone The sub-addressing scheme indicates the prefix length: /127 for zone
address sub-scheme, /120 or /112 for Vlong address sub-scheme. The address sub-scheme, /120 or /112 for Vlong address sub-scheme. The
first address of the prefix is the ACP address. All other addresses first address of the prefix is the ACP address. All other addresses
in the prefix are for other uses by the ACP node as described in the in the prefix are for other uses by the ACP node as described in the
zone and Vlong addressing sub scheme sections. The ACP address zone and Vlong addressing sub scheme sections. The ACP address
prefix itself is then signaled by the ACP node into the ACP routing prefix itself is then signaled by the ACP node into the ACP routing
protocol (see Section 6.11) to establish IPv6 reachability across the protocol (see Section 6.12) to establish IPv6 reachability across the
ACP. ACP.
The choice of addressing sub-scheme and prefix-length in the Vlong The choice of addressing sub-scheme and prefix-length in the Vlong
address sub-scheme is subject to ACP registrar policy. It could be address sub-scheme is subject to ACP registrar policy. It could be
an ACP domain wide policy, or a per ACP node or per ACP node type an ACP domain wide policy, or a per ACP node or per ACP node type
policy. For example, in BRSKI, the ACP registrar is aware of the policy. For example, in BRSKI, the ACP registrar is aware of the
IDevID certificate of the candidate ACP node, which typically IDevID certificate of the candidate ACP node, which typically
contains a "serialNumber" attribute in the subjects field contains a "serialNumber" attribute in the subjects field
distinguished name encoding that is often indicating the node's distinguished name encoding that is often indicating the node's
vendor and device type and can be used to drive a policy selecting an vendor and device type and can be used to drive a policy selecting an
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If allocated addresses can not be remembered by registrars, then it If allocated addresses can not be remembered by registrars, then it
is necessary to either use a new value for the Register-ID field in is necessary to either use a new value for the Register-ID field in
the ACP addresses, or determine allocated ACP addresses from the ACP addresses, or determine allocated ACP addresses from
determining the addresses of reachable ACP nodes, which is not determining the addresses of reachable ACP nodes, which is not
necessarily the set of all ACP nodes. Non-tracked ACP addresses can necessarily the set of all ACP nodes. Non-tracked ACP addresses can
be reclaimed by revoking or not renewing their certificates and be reclaimed by revoking or not renewing their certificates and
instead handing out new certificate with new addresses (for example instead handing out new certificate with new addresses (for example
with a new Registrar-ID value). Note that such strategies may with a new Registrar-ID value). Note that such strategies may
require coordination amongst registrars. require coordination amongst registrars.
6.10.7.4. Address/Prefix Persistence 6.11.7.4. Address/Prefix Persistence
When an ACP certificate is renewed or rekeyed via EST or other When an ACP certificate is renewed or rekeyed via EST or other
mechanisms, the ACP address/prefix in the acp-node-name field MUST be mechanisms, the ACP address/prefix in the acp-node-name field MUST be
maintained unless security issues or violations of the unique address maintained unless security issues or violations of the unique address
assignment requirements exist or are suspected by the ACP registrar. assignment requirements exist or are suspected by the ACP registrar.
ACP address information SHOULD be maintained even when the renewing/ ACP address information SHOULD be maintained even when the renewing/
rekeying ACP registrar is not the same as the one that enrolled the rekeying ACP registrar is not the same as the one that enrolled the
prior ACP certificate. See Section 9.2.4 for an example. prior ACP certificate. See Section 9.2.4 for an example.
ACP address information SHOULD also be maintained even after an ACP ACP address information SHOULD also be maintained even after an ACP
certificate did expire or failed. See Section 6.1.5.5 and certificate did expire or failed. See Section 6.2.5.5 and
Section 6.1.5.6. Section 6.2.5.6.
6.10.7.5. Further Details 6.11.7.5. Further Details
Section 9.2 discusses further informative details of ACP registrars: Section 9.2 discusses further informative details of ACP registrars:
What interactions registrars need, what parameters they require, What interactions registrars need, what parameters they require,
certificate renewal and limitations, use of sub-CAs on registrars and certificate renewal and limitations, use of sub-CAs on registrars and
centralized policy control. centralized policy control.
6.11. Routing in the ACP 6.12. Routing in the ACP
Once ULA address are set up all autonomic entities should run a Once ULA address are set up all autonomic entities should run a
routing protocol within the autonomic control plane context. This routing protocol within the autonomic control plane context. This
routing protocol distributes the ULA created in the previous section routing protocol distributes the ULA created in the previous section
for reachability. The use of the autonomic control plane specific for reachability. The use of the autonomic control plane specific
context eliminates the probable clash with Data-Plane routing tables context eliminates the probable clash with Data-Plane routing tables
and also secures the ACP from interference from the configuration and also secures the ACP from interference from the configuration
mismatch or incorrect routing updates. mismatch or incorrect routing updates.
The establishment of the routing plane and its parameters are The establishment of the routing plane and its parameters are
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channels of the ACP are encrypted, and this routing runs only inside channels of the ACP are encrypted, and this routing runs only inside
the ACP. the ACP.
The routing protocol inside the ACP is RPL ([RFC6550]). See The routing protocol inside the ACP is RPL ([RFC6550]). See
Appendix A.4 for more details on the choice of RPL. Appendix A.4 for more details on the choice of RPL.
RPL adjacencies are set up across all ACP channels in the same domain RPL adjacencies are set up across all ACP channels in the same domain
including all its routing subdomains. See Appendix A.7 for more including all its routing subdomains. See Appendix A.7 for more
details. details.
6.11.1. ACP RPL Profile 6.12.1. ACP RPL Profile
The following is a description of the RPL profile that ACP nodes need The following is a description of the RPL profile that ACP nodes need
to support by default. The format of this section is derived from to support by default. The format of this section is derived from
[I-D.ietf-roll-applicability-template]. [I-D.ietf-roll-applicability-template].
6.11.1.1. Overview 6.12.1.1. Overview
RPL Packet Information (RPI) defined in [RFC6550], section 11.2 RPL Packet Information (RPI) defined in [RFC6550], section 11.2
defines the data packet artefacts required or beneficial in defines the data packet artefacts required or beneficial in
forwarding of packets routed by RPL. This profile does not use RPI forwarding of packets routed by RPL. This profile does not use RPI
for better compatibility with accelerated hardware forwarding planes for better compatibility with accelerated hardware forwarding planes
which most often does not support the Hop-by-Hop headers used for which most often does not support the Hop-by-Hop headers used for
RPI, but also to avoid the overhead of the RPI header on the wire and RPI, but also to avoid the overhead of the RPI header on the wire and
cost of adding/removing them. cost of adding/removing them.
6.11.1.1.1. Single Instance 6.12.1.1.1. Single Instance
To avoid the need for RPI, the ACP RPL profile uses a simple To avoid the need for RPI, the ACP RPL profile uses a simple
destination prefix based routing/forwarding table. To achieve this, destination prefix based routing/forwarding table. To achieve this,
the profiles uses only one RPL instanceID. This single instanceID the profiles uses only one RPL instanceID. This single instanceID
can contain only one Destination Oriented Directed Acyclic Graph can contain only one Destination Oriented Directed Acyclic Graph
(DODAG), and the routing/forwarding table can therefore only (DODAG), and the routing/forwarding table can therefore only
calculate a single class of service ("best effort towards the primary calculate a single class of service ("best effort towards the primary
NOC/root") and cannot create optimized routing paths to accomplish NOC/root") and cannot create optimized routing paths to accomplish
latency or energy goals between any two nodes. latency or energy goals between any two nodes.
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Plane forwarding failures including choosing a different root when Plane forwarding failures including choosing a different root when
the primary one fails. the primary one fails.
The benefit of this profile, especially compared to other IGPs is The benefit of this profile, especially compared to other IGPs is
that it does not calculate routes for node reachable through the same that it does not calculate routes for node reachable through the same
interface as the DODAG root. This RPL profile can therefore scale to interface as the DODAG root. This RPL profile can therefore scale to
much larger number of ACP nodes in the same amount of compute and much larger number of ACP nodes in the same amount of compute and
memory than other routing protocols. Especially on nodes that are memory than other routing protocols. Especially on nodes that are
leafs of the topology or those close to those leafs. leafs of the topology or those close to those leafs.
6.11.1.1.2. Reconvergence 6.12.1.1.2. Reconvergence
In RPL profiles where RPL Packet Information (RPI, see In RPL profiles where RPL Packet Information (RPI, see
Section 6.11.1.13) is present, it is also used to trigger Section 6.12.1.13) is present, it is also used to trigger
reconvergence when misrouted, for example looping, packets are reconvergence when misrouted, for example looping, packets are
recognized because of their RPI data. This helps to minimize RPL recognized because of their RPI data. This helps to minimize RPL
signaling traffic especially in networks without stable topology and signaling traffic especially in networks without stable topology and
slow links. slow links.
The ACP RPL profile instead relies on quick reconverging the DODAG by The ACP RPL profile instead relies on quick reconverging the DODAG by
recognizing link state change (down/up) and triggering reconvergence recognizing link state change (down/up) and triggering reconvergence
signaling as described in Section 6.11.1.7. Since links in the ACP signaling as described in Section 6.12.1.7. Since links in the ACP
are assumed to be mostly reliable (or have link layer protection are assumed to be mostly reliable (or have link layer protection
against loss) and because there is no stretch according to against loss) and because there is no stretch according to
Section 6.11.1.7, loops caused by loss of RPL routing protocol Section 6.12.1.7, loops caused by loss of RPL routing protocol
signaling packets should be exceedingly rare. signaling packets should be exceedingly rare.
In addition, there are a variety of mechanisms possible in RPL to In addition, there are a variety of mechanisms possible in RPL to
further avoid temporary loops RECOMMENDED to be used for the ACPL RPL further avoid temporary loops RECOMMENDED to be used for the ACPL RPL
profile: DODAG Information Objects (DIOs) SHOULD be sent 2 or 3 times profile: DODAG Information Objects (DIOs) SHOULD be sent 2 or 3 times
to inform children when losing the last parent. The technique in to inform children when losing the last parent. The technique in
[RFC6550] section 8.2.2.6. (Detaching) SHOULD be favored over that [RFC6550] section 8.2.2.6. (Detaching) SHOULD be favored over that
in section 8.2.2.5., (Poisoning) because it allows local in section 8.2.2.5., (Poisoning) because it allows local
connectivity. Nodes SHOULD select more than one parent, at least 3 connectivity. Nodes SHOULD select more than one parent, at least 3
if possible, and send Destination Advertisement Objects (DAO)s to all if possible, and send Destination Advertisement Objects (DAO)s to all
of them in parallel. of them in parallel.
Additionally, failed ACP tunnels can be quickly discovered trough the Additionally, failed ACP tunnels can be quickly discovered trough the
secure channel protocol mechanisms such as IKEv2 Dead Peer Detection. secure channel protocol mechanisms such as IKEv2 Dead Peer Detection.
This can function as a replacement for a Low-power and Lossy This can function as a replacement for a Low-power and Lossy
Networks' (LLN's) Expected Transmission Count (ETX) feature that is Networks' (LLN's) Expected Transmission Count (ETX) feature that is
not used in this profile. A failure of an ACP tunnel should not used in this profile. A failure of an ACP tunnel should
imediately signal the RPL control plane to pick a different parent. imediately signal the RPL control plane to pick a different parent.
6.11.1.2. RPL Instances 6.12.1.2. RPL Instances
Single RPL instance. Default RPLInstanceID = 0. Single RPL instance. Default RPLInstanceID = 0.
6.11.1.3. Storing vs. Non-Storing Mode 6.12.1.3. Storing vs. Non-Storing Mode
RPL Mode of Operations (MOP): MUST support mode 2 - "Storing Mode of RPL Mode of Operations (MOP): MUST support mode 2 - "Storing Mode of
Operations with no multicast support". Implementations MAY support Operations with no multicast support". Implementations MAY support
mode 3 ("... with multicast support" as that is a superset of mode mode 3 ("... with multicast support" as that is a superset of mode
2). Note: Root indicates mode in DIO flow. 2). Note: Root indicates mode in DIO flow.
6.11.1.4. DAO Policy 6.12.1.4. DAO Policy
Proactive, aggressive DAO state maintenance: Proactive, aggressive DAO state maintenance:
* Use K-flag in unsolicited DAO indicating change from previous * Use K-flag in unsolicited DAO indicating change from previous
information (to require DAO-ACK). information (to require DAO-ACK).
* Retry such DAO DAO-RETRIES(3) times with DAO- ACK_TIME_OUT(256ms) * Retry such DAO DAO-RETRIES(3) times with DAO- ACK_TIME_OUT(256ms)
in between. in between.
6.11.1.5. Path Metric 6.12.1.5. Path Metric
Use Hopcount according to [RFC6551]. Note that this is solely for Use Hopcount according to [RFC6551]. Note that this is solely for
diagnostic purposes as it is not used by the objective function. diagnostic purposes as it is not used by the objective function.
6.11.1.6. Objective Function 6.12.1.6. Objective Function
Objective Function (OF): Use OF0 [RFC6552]. No use of metric Objective Function (OF): Use OF0 [RFC6552]. No use of metric
containers. containers.
rank_factor: Derived from link speed: <= 100Mbps: rank_factor: Derived from link speed: <= 100Mbps:
LOW_SPEED_FACTOR(5), else HIGH_SPEED_FACTOR(1) LOW_SPEED_FACTOR(5), else HIGH_SPEED_FACTOR(1)
This is a simple rank differentiation between typical "low speed" or This is a simple rank differentiation between typical "low speed" or
"IoT" links that commonly max out at 100 Mbps and typical "IoT" links that commonly max out at 100 Mbps and typical
infrastructure links with speeds of 1 Gbps or higher. Given how the infrastructure links with speeds of 1 Gbps or higher. Given how the
path selection for the ACP focusses only on reachability but not on path selection for the ACP focusses only on reachability but not on
path cost optimization, no attempts at finer grained path path cost optimization, no attempts at finer grained path
optimization are made. optimization are made.
6.11.1.7. DODAG Repair 6.12.1.7. DODAG Repair
Global Repair: we assume stable links and ranks (metrics), so no need Global Repair: we assume stable links and ranks (metrics), so there
to periodically rebuild DODAG. DODAG version only incremented under is no need to periodically rebuild the DODAG. The DODAG version is
catastrophic events (e.g., administrative action). only incremented under catastrophic events (e.g., administrative
action).
Local Repair: As soon as link breakage is detected, send No-Path DAO Local Repair: As soon as link breakage is detected, the ACP node send
for all the targets that were reachable only via this link. As soon No-Path DAO for all the targets that were reachable only via this
as link repair is detected, validate if this link provides you a link. As soon as link repair is detected, the ACP node validates if
better parent. If so, compute your new rank, and send new DIO that this link provides a better parent. If so, a new rank is computed by
advertises your new rank. Then send a DAO with a new path sequence the ACP node and it sends new DIO that advertise the new rank. Then
about yourself. it sends a DAO with a new path sequence about itself.
When using ACP multi-access virtual interfaces, local repair can be When using ACP multi-access virtual interfaces, local repair can be
triggered directly by peer breakage, see Section 6.12.5.2.2. triggered directly by peer breakage, see Section 6.13.5.2.2.
stretch_rank: none provided ("not stretched"). stretch_rank: none provided ("not stretched").
Data Path Validation: Not used. Data Path Validation: Not used.
Trickle: Not used. Trickle: Not used.
6.11.1.8. Multicast 6.12.1.8. Multicast
Not used yet but possible because of the selected mode of operations. Not used yet but possible because of the selected mode of operations.
6.11.1.9. Security 6.12.1.9. Security
[RFC6550] security not used, substituted by ACP security. [RFC6550] security not used, substituted by ACP security.
Because the ACP links already include provisions for confidentiality Because the ACP links already include provisions for confidentiality
and integrity protection, their usage at the RPL layer would be and integrity protection, their usage at the RPL layer would be
redundant, and so RPL security is not used. redundant, and so RPL security is not used.
6.11.1.10. P2P communications 6.12.1.10. P2P communications
Not used. Not used.
6.11.1.11. IPv6 address configuration 6.12.1.11. IPv6 address configuration
Every ACP node (RPL node) announces an IPv6 prefix covering the Every ACP node (RPL node) announces an IPv6 prefix covering the
address(es) used in the ACP node. The prefix length depends on the address(es) used in the ACP node. The prefix length depends on the
chosen addressing sub-scheme of the ACP address provisioned into the chosen addressing sub-scheme of the ACP address provisioned into the
certificate of the ACP node, e.g., /127 for Zone Addressing Sub- certificate of the ACP node, e.g., /127 for Zone Addressing Sub-
Scheme or /112 or /120 for Vlong addressing sub-scheme. See Scheme or /112 or /120 for Vlong addressing sub-scheme. See
Section 6.10 for more details. Section 6.11 for more details.
Every ACP node MUST install a black hole (aka null) route for Every ACP node MUST install a black hole (aka null) route for
whatever ACP address space that it advertises (i.e.: the /96 or whatever ACP address space that it advertises (i.e.: the /96 or
/127). This is avoid routing loops for addresses that an ACP node /127). This is avoid routing loops for addresses that an ACP node
has not (yet) used. has not (yet) used.
6.11.1.12. Administrative parameters 6.12.1.12. Administrative parameters
Administrative Preference ([RFC6550], 3.2.6 - to become root): Administrative Preference ([RFC6550], 3.2.6 - to become root):
Indicated in DODAGPreference field of DIO message. Indicated in DODAGPreference field of DIO message.
* Explicit configured "root": 0b100 * Explicit configured "root": 0b100
* ACP registrar (Default): 0b011 * ACP registrar (Default): 0b011
* ACP-connect (non-registrar): 0b010 * ACP-connect (non-registrar): 0b010
* Default: 0b001. * Default: 0b001.
6.11.1.13. RPL Packet Information 6.12.1.13. RPL Packet Information
RPI is not required in the ACP RPL profile for the following reasons. RPI is not required in the ACP RPL profile for the following reasons.
One RPI option is the RPL Source Routing Header (SRH) [RFC6554] which One RPI option is the RPL Source Routing Header (SRH) [RFC6554] which
is not necessary because the ACP RPL profile uses storing mode where is not necessary because the ACP RPL profile uses storing mode where
each hop has the necessary next-hop forwarding information. each hop has the necessary next-hop forwarding information.
The simpler RPL Option header [RFC6553] is also not necessary in this The simpler RPL Option header [RFC6553] is also not necessary in this
profile, because it uses a single RPL instance and data path profile, because it uses a single RPL instance and data path
validation is also not used. validation is also not used.
6.11.1.14. Unknown Destinations 6.12.1.14. Unknown Destinations
Because RPL minimizes the size of the routing and forwarding table, Because RPL minimizes the size of the routing and forwarding table,
prefixes reachable through the same interface as the RPL root are not prefixes reachable through the same interface as the RPL root are not
known on every ACP node. Therefore traffic to unknown destination known on every ACP node. Therefore traffic to unknown destination
addresses can only be discovered at the RPL root. The RPL root addresses can only be discovered at the RPL root. The RPL root
SHOULD have attach safe mechanisms to operationally discover and log SHOULD have attach safe mechanisms to operationally discover and log
such packets. such packets.
As this requirement places additional constraints on the Data-Plane As this requirement places additional constraints on the Data-Plane
functionality of the RPL root, it does not apply to "normal" nodes functionality of the RPL root, it does not apply to "normal" nodes
that are not configured to have special functionality (i.e., the that are not configured to have special functionality (i.e., the
adminstrative parameter from Section 6.11.1.12 has value 0b001). If adminstrative parameter from Section 6.12.1.12 has value 0b001). If
the ACP network is degraded to the point where there are no nodes the ACP network is degraded to the point where there are no nodes
that could be configured as root, registrar, or ACP-connect nodes, it that could be configured as root, registrar, or ACP-connect nodes, it
is possible that the RPL root ( and thus the ACP as a whole) would be is possible that the RPL root ( and thus the ACP as a whole) would be
unable to detect traffic to unknown destinations. However, in the unable to detect traffic to unknown destinations. However, in the
absence of nodes with administrative preference other than 0b001, absence of nodes with administrative preference other than 0b001,
there is also unlikely to be a way to get diagnostic information out there is also unlikely to be a way to get diagnostic information out
of the ACP, so detection of traffic to unknown destinations would not of the ACP, so detection of traffic to unknown destinations would not
be actionable anyway. be actionable anyway.
6.12. General ACP Considerations 6.13. General ACP Considerations
Since channels are by default established between adjacent neighbors, Since channels are by default established between adjacent neighbors,
the resulting overlay network does hop-by-hop encryption. Each node the resulting overlay network does hop-by-hop encryption. Each node
decrypts incoming traffic from the ACP, and encrypts outgoing traffic decrypts incoming traffic from the ACP, and encrypts outgoing traffic
to its neighbors in the ACP. Routing is discussed in Section 6.11. to its neighbors in the ACP. Routing is discussed in Section 6.12.
6.12.1. Performance 6.13.1. Performance
There are no performance requirements against ACP implementations There are no performance requirements against ACP implementations
defined in this document because the performance requirements depend defined in this document because the performance requirements depend
on the intended use case. It is expected that full autonomic node on the intended use case. It is expected that full autonomic node
with a wide range of ASA can require high forwarding plane with a wide range of ASA can require high forwarding plane
performance in the ACP, for example for telemetry. Implementations performance in the ACP, for example for telemetry. Implementations
of ACP to solely support traditional/SDN style use cases can benefit of ACP to solely support traditional/SDN style use cases can benefit
from ACP at lower performance, especially if the ACP is used only for from ACP at lower performance, especially if the ACP is used only for
critical operations, e.g., when the Data-Plane is not available. The critical operations, e.g., when the Data-Plane is not available. The
design of the ACP as specified in this document is intended to design of the ACP as specified in this document is intended to
support a wide range of performance options: It is intended to allow support a wide range of performance options: It is intended to allow
software-only implementations at potentially low performance, but can software-only implementations at potentially low performance, but can
also support high performance options. See [RFC8368] for more also support high performance options. See [RFC8368] for more
details. details.
6.12.2. Addressing of Secure Channels 6.13.2. Addressing of Secure Channels
In order to be independent of the Data-Plane routing and addressing, In order to be independent of the Data-Plane routing and addressing,
the GRASP discovered ACP secure channels use IPv6 link local the GRASP discovered ACP secure channels use IPv6 link local
addresses between adjacent neighbors. Note: Section 8.2 specifies addresses between adjacent neighbors. Note: Section 8.2 specifies
extensions in which secure channels are configured tunnels operating extensions in which secure channels are configured tunnels operating
over the Data-Plane, so those secure channels cannot be independent over the Data-Plane, so those secure channels cannot be independent
of the Data-Plane. of the Data-Plane.
To avoid that Data-Plane configuration can impact the operations of To avoid that Data-Plane configuration can impact the operations of
the IPv6 (link-local) interface/address used for ACP channels, the IPv6 (link-local) interface/address used for ACP channels,
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(virtual) interface with a separate IPv6 link-local address can be (virtual) interface with a separate IPv6 link-local address can be
used. For example, the ACP interface could be run over a separate used. For example, the ACP interface could be run over a separate
MAC address of an underlying L2 (Ethernet) interface. For more MAC address of an underlying L2 (Ethernet) interface. For more
details and options, see Appendix A.10.2. details and options, see Appendix A.10.2.
Note that other (non-ideal) implementation choices may introduce Note that other (non-ideal) implementation choices may introduce
additional undesired dependencies against the Data-Plane. For additional undesired dependencies against the Data-Plane. For
example shared code and configuration of the secure channel protocols example shared code and configuration of the secure channel protocols
(IPsec / DTLS). (IPsec / DTLS).
6.12.3. MTU 6.13.3. MTU
The MTU for ACP secure channels MUST be derived locally from the The MTU for ACP secure channels MUST be derived locally from the
underlying link MTU minus the secure channel encapsulation overhead. underlying link MTU minus the secure channel encapsulation overhead.
ACP secure Channel protocols do not need to perform MTU discovery ACP secure Channel protocols do not need to perform MTU discovery
because they are built across L2 adjacencies - the MTU on both sides because they are built across L2 adjacencies - the MTU on both sides
connecting to the L2 connection are assumed to be consistent. connecting to the L2 connection are assumed to be consistent.
Extensions to ACP where the ACP is for example tunneled need to Extensions to ACP where the ACP is for example tunneled need to
consider how to guarantee MTU consistency. This is an issue of consider how to guarantee MTU consistency. This is an issue of
tunnels, not an issue of running the ACP across a tunnel. Transport tunnels, not an issue of running the ACP across a tunnel. Transport
stacks running across ACP can perform normal PMTUD (Path MTU stacks running across ACP can perform normal PMTUD (Path MTU
Discovery). Because the ACP is meant to be prioritize reliability Discovery). Because the ACP is meant to be prioritize reliability
over performance, they MAY opt to only expect IPv6 minimum MTU (1280) over performance, they MAY opt to only expect IPv6 minimum MTU (1280)
to avoid running into PMTUD implementation bugs or underlying link to avoid running into PMTUD implementation bugs or underlying link
MTU mismatch problems. MTU mismatch problems.
6.12.4. Multiple links between nodes 6.13.4. Multiple links between nodes
If two nodes are connected via several links, the ACP SHOULD be If two nodes are connected via several links, the ACP SHOULD be
established across every link, but it is possible to establish the established across every link, but it is possible to establish the
ACP only on a sub-set of links. Having an ACP channel on every link ACP only on a sub-set of links. Having an ACP channel on every link
has a number of advantages, for example it allows for a faster has a number of advantages, for example it allows for a faster
failover in case of link failure, and it reflects the physical failover in case of link failure, and it reflects the physical
topology more closely. Using a subset of links (for example, a topology more closely. Using a subset of links (for example, a
single link), reduces resource consumption on the node, because state single link), reduces resource consumption on the node, because state
needs to be kept per ACP channel. The negotiation scheme explained needs to be kept per ACP channel. The negotiation scheme explained
in Section 6.5 allows Alice (the node with the higher ACP address) to in Section 6.6 allows the Decider (the node with the higher ACP
drop all but the desired ACP channels to Bob - and Bob will not re- address) to drop all but the desired ACP channels to the Follower -
try to build these secure channels from his side unless Alice shows and the Follower will not re-try to build these secure channels from
up with a previously unknown GRASP announcement (e.g., on a different its side unless the Decider shows up with a previously unknown GRASP
link or with a different address announced in GRASP). announcement (e.g., on a different link or with a different address
announced in GRASP).
6.12.5. ACP interfaces 6.13.5. ACP interfaces
The ACP VRF has conceptually two type of interfaces: The "ACP The ACP VRF has conceptually two type of interfaces: The "ACP
Loopback interface(s)" to which the ACP ULA address(es) are assigned Loopback interface(s)" to which the ACP ULA address(es) are assigned
and the "ACP virtual interfaces" that are mapped to the ACP secure and the "ACP virtual interfaces" that are mapped to the ACP secure
channels. channels.
6.12.5.1. ACP loopback interfaces 6.13.5.1. ACP loopback interfaces
For autonomous operations of the ACP, as described in Section 6 and For autonomous operations of the ACP, as described in Section 6 and
Section 7, the ACP node uses the first address from the N bit ACP Section 7, the ACP node uses the first address from the N bit ACP
prefix (N = 128 - number of Vbits of the ACP address) assigned to the prefix (N = 128 - number of Vbits of the ACP address) assigned to the
node. This address is assigned with an adddress prefix of N or node. This address is assigned with an adddress prefix of N or
larger to a loopback interface. larger to a loopback interface.
Other addresses from the prefix can be used by the ACP of the node as Other addresses from the prefix can be used by the ACP of the node as
desired. The autonomous operations of the ACP does not require desired. The autonomous operations of the ACP does not require
additional global scope IPv6 addresses, they are instead intended for additional global scope IPv6 addresses, they are instead intended for
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A loopback interface used for the ACP MUST NOT have connectivity to A loopback interface used for the ACP MUST NOT have connectivity to
other nodes. other nodes.
The following reviews the reasons for the choice of loopback The following reviews the reasons for the choice of loopback
addresses for ACP addresses is based on the IPv6 address architecture addresses for ACP addresses is based on the IPv6 address architecture
and common challenges: and common challenges:
1. IPv6 addresses are assigned to interfaces, not nodes. IPv6 1. IPv6 addresses are assigned to interfaces, not nodes. IPv6
continues the IPv4 model that a subnet prefix is associated with continues the IPv4 model that a subnet prefix is associated with
one link, see [RFC4291], Section 2.1. one link, see [RFC4291], Section 2.1.
2. IPv6 implementations do commonly not allow to assign the same 2. IPv6 implementations commonly do not allow assignment of the same
IPv6 global scope address in the same VRF to more than one IPv6 global scope address in the same VRF to more than one
interface. interface.
3. Global scope addresses assigned to interfaces that are connecting 3. Global scope addresses assigned to interfaces that are connecting
to other nodes (external interfaces) may not be stable addresses to other nodes (external interfaces) may not be stable addresses
for communications because any such interface could fail due to for communications because any such interface could fail due to
reasons external to the node. This could render the addresses reasons external to the node. This could render the addresses
assigned to that interface unusable. assigned to that interface unusable.
4. If failure of the subnet does not result in bringing down the 4. If failure of the subnet does not result in bringing down the
interface and making the addresses unusable, it could result in interface and making the addresses unusable, it could result in
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highly undesirable because it should attempt to minimize the per- highly undesirable because it should attempt to minimize the per-
node overhead of the ACP VRF. node overhead of the ACP VRF.
9. For all these reasons, the ACP addressing schemes do not consider 9. For all these reasons, the ACP addressing schemes do not consider
ACP addresses for subnets connecting ACP nodes. ACP addresses for subnets connecting ACP nodes.
Note that [RFC8402] introduces the term Node-SID to refer to IGP Note that [RFC8402] introduces the term Node-SID to refer to IGP
prefix segments that identify a specific rouer, for example on a prefix segments that identify a specific rouer, for example on a
loopback interface. An ACP loopback address prefix may similarily be loopback interface. An ACP loopback address prefix may similarily be
called an ACP Node Identifier. called an ACP Node Identifier.
6.12.5.2. ACP virtual interfaces 6.13.5.2. ACP virtual interfaces
Any ACP secure channel to another ACP node is mapped to ACP virtual Any ACP secure channel to another ACP node is mapped to ACP virtual
interfaces in one of the following ways. This is independent of the interfaces in one of the following ways. This is independent of the
chosen secure channel protocol (IPsec, DTLS or other future protocol chosen secure channel protocol (IPsec, DTLS or other future protocol
- standards or non-standards). - standards or non-standards).
Note that all the considerations described here are assuming point- Note that all the considerations described here are assuming point-
to-point secure channel associations. Mapping multi-party secure to-point secure channel associations. Mapping multi-party secure
channel associations such as [RFC6407] is out of scope. channel associations such as [RFC6407] is out of scope.
6.12.5.2.1. ACP point-to-point virtual interfaces 6.13.5.2.1. ACP point-to-point virtual interfaces
In this option, each ACP secure channel is mapped into a separate In this option, each ACP secure channel is mapped into a separate
point-to-point ACP virtual interface. If a physical subnet has more point-to-point ACP virtual interface. If a physical subnet has more
than two ACP capable nodes (in the same domain), this implementation than two ACP capable nodes (in the same domain), this implementation
approach will lead to a full mesh of ACP virtual interfaces between approach will lead to a full mesh of ACP virtual interfaces between
them. them.
When the secure channel protocol determines a peer to be dead, this When the secure channel protocol determines a peer to be dead, this
SHOULD result in indicating link breakage to trigger RPL DODAG SHOULD result in indicating link breakage to trigger RPL DODAG
repair, see Section 6.11.1.7. repair, see Section 6.12.1.7.
6.12.5.2.2. ACP multi-access virtual interfaces 6.13.5.2.2. ACP multi-access virtual interfaces
In a more advanced implementation approach, the ACP will construct a In a more advanced implementation approach, the ACP will construct a
single multi-access ACP virtual interface for all ACP secure channels single multi-access ACP virtual interface for all ACP secure channels
to ACP capable nodes reachable across the same underlying (physical) to ACP capable nodes reachable across the same underlying (physical)
subnet. IPv6 link-local multicast packets sent into an ACP multi- subnet. IPv6 link-local multicast packets sent into an ACP multi-
access virtual interface are replicated to every ACP secure channel access virtual interface are replicated to every ACP secure channel
mapped into the ACP multicast-access virtual interface. IPv6 unicast mapped into the ACP multicast-access virtual interface. IPv6 unicast
packets sent into an ACP multi-access virtual interface are sent to packets sent into an ACP multi-access virtual interface are sent to
the ACP secure channel that belongs to the ACP neighbor that is the the ACP secure channel that belongs to the ACP neighbor that is the
next-hop in the ACP forwarding table entry used to reach the packets next-hop in the ACP forwarding table entry used to reach the packets
destination address. destination address.
When the secure channel protocol determines a peer to be dead for a When the secure channel protocol determines a peer to be dead for a
secure channel mapped into an ACP multi-access virtual interface, secure channel mapped into an ACP multi-access virtual interface,
this SHOULD result in signaling breakage of that peer to RPL, so it this SHOULD result in signaling breakage of that peer to RPL, so it
can trigger RPL DODAG repair, see Section 6.11.1.7. can trigger RPL DODAG repair, see Section 6.12.1.7.
There is no requirement for all ACP nodes on the same multi-access There is no requirement for all ACP nodes on the same multi-access
subnet to use the same type of ACP virtual interface. This is purely subnet to use the same type of ACP virtual interface. This is purely
a node local decision. a node local decision.
ACP nodes MUST perform standard IPv6 operations across ACP virtual ACP nodes MUST perform standard IPv6 operations across ACP virtual
interfaces including SLAAC (Stateless Address Auto-Configuration) - interfaces including SLAAC (Stateless Address Auto-Configuration) -
[RFC4862]) to assign their IPv6 link local address on the ACP virtual [RFC4862]) to assign their IPv6 link local address on the ACP virtual
interface and ND (Neighbor Discovery - [RFC4861]) to discover which interface and ND (Neighbor Discovery - [RFC4861]) to discover which
IPv6 link-local neighbor address belongs to which ACP secure channel IPv6 link-local neighbor address belongs to which ACP secure channel
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example simpler to build services with topology awareness inside the example simpler to build services with topology awareness inside the
ACP VRF in the same way as they could have been built running ACP VRF in the same way as they could have been built running
natively on the multi-access interfaces. natively on the multi-access interfaces.
Consider also the impact of point-to-point vs. multi-access virtual Consider also the impact of point-to-point vs. multi-access virtual
interface on the efficiency of flooding via link local multicasted interface on the efficiency of flooding via link local multicasted
messages: messages:
Assume a LAN with three ACP neighbors, Alice, Bob and Carol. Alice's Assume a LAN with three ACP neighbors, Alice, Bob and Carol. Alice's
ACP GRASP wants to send a link-local GRASP multicast message to Bob ACP GRASP wants to send a link-local GRASP multicast message to Bob
and Carol. If Alice's ACP emulates the LAN as one point-to-point and Carol. If Alice's ACP emulates the LAN as per-peer, point-to-
virtual interface to Bob and one to Carol, The sending applications point virtual interfaces, one to Bob and one to Carol, Alice's ACP
itself will send two copies, if Alice's ACP emulates a LAN, GRASP GRASP will send two copies of multicast GRASP messages: One to Bob
will send one packet and the ACP will replicate it. The result is and one to Carol. If Alice's ACP emulates a LAN via a multipoint
the same. The difference happens when Bob and Carol receive their virtual interface, Alice's ACP GRASP will send one packet to that
interface and the ACP multipoint virtual interface will replicate the
packet to each secure channel, one to Bob, one to Carol. The result
is the same. The difference happens when Bob and Carol receive their
packet. If they use ACP point-to-point virtual interfaces, their packet. If they use ACP point-to-point virtual interfaces, their
GRASP instance would forward the packet from Alice to each other as GRASP instance would forward the packet from Alice to each other as
part of the GRASP flooding procedure. These packets are unnecessary part of the GRASP flooding procedure. These packets are unnecessary
and would be discarded by GRASP on receipt as duplicates (by use of and would be discarded by GRASP on receipt as duplicates (by use of
the GRASP Session ID). If Bob and Carol's ACP would emulate a multi- the GRASP Session ID). If Bob and Carol's ACP would emulate a multi-
access virtual interface, then this would not happen, because GRASPs access virtual interface, then this would not happen, because GRASPs
flooding procedure does not replicate back packets to the interface flooding procedure does not replicate back packets to the interface
that they were received from. that they were received from.
Note that link-local GRASP multicast messages are not sent directly Note that link-local GRASP multicast messages are not sent directly
as IPv6 link-local multicast UDP messages into ACP virtual as IPv6 link-local multicast UDP messages into ACP virtual
interfaces, but instead into ACP GRASP virtual interfaces, that are interfaces, but instead into ACP GRASP virtual interfaces, that are
layered on top of ACP virtual interfaces to add TCP reliability to layered on top of ACP virtual interfaces to add TCP reliability to
link-local multicast GRASP messages. Nevertheless, these ACP GRASP link-local multicast GRASP messages. Nevertheless, these ACP GRASP
virtual interfaces perform the same replication of message and, virtual interfaces perform the same replication of message and,
therefore, result in the same impact on flooding. See Section 6.8.2 therefore, result in the same impact on flooding. See Section 6.9.2
for more details. for more details.
RPL does support operations and correct routing table construction RPL does support operations and correct routing table construction
across non-broadcast multi-access (NBMA) subnets. This is common across non-broadcast multi-access (NBMA) subnets. This is common
when using many radio technologies. When such NBMA subnets are used, when using many radio technologies. When such NBMA subnets are used,
they MUST NOT be represented as ACP multi-access virtual interfaces they MUST NOT be represented as ACP multi-access virtual interfaces
because the replication of IPv6 link-local multicast messages will because the replication of IPv6 link-local multicast messages will
not reach all NBMA subnet neighbors. In result, GRASP message not reach all NBMA subnet neighbors. In result, GRASP message
flooding would fail. Instead, each ACP secure channel across such an flooding would fail. Instead, each ACP secure channel across such an
interface MUST be represented as a ACP point-to-point virtual interface MUST be represented as a ACP point-to-point virtual
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L3 VLAN interface. With the aforementioned changes for DULL GRASP, L3 VLAN interface. With the aforementioned changes for DULL GRASP,
ACP can simply operate on the L3 VLAN interfaces, so no further ACP can simply operate on the L3 VLAN interfaces, so no further
(hardware) forwarding changes are required to make ACP operate on L2 (hardware) forwarding changes are required to make ACP operate on L2
ports. This is possible because the ACP secure channel protocols ports. This is possible because the ACP secure channel protocols
only use link-local IPv6 unicast packets, and these packets will be only use link-local IPv6 unicast packets, and these packets will be
sent to the correct L2 port towards the peer by the VLAN logic of the sent to the correct L2 port towards the peer by the VLAN logic of the
device. device.
This is sufficient when p2p ACP virtual interfaces are established to This is sufficient when p2p ACP virtual interfaces are established to
every ACP peer. When it is desired to create multi-access ACP every ACP peer. When it is desired to create multi-access ACP
virtual interfaces (see Section 6.12.5.2.2), it is REQIURED not to virtual interfaces (see Section 6.13.5.2.2), it is REQIURED not to
coalesce all the ACP secure channels on the same L3 VLAN interface, coalesce all the ACP secure channels on the same L3 VLAN interface,
but only all those on the same L2 port. but only all those on the same L2 port.
If VLAN tagging is used, then all the above described logic only If VLAN tagging is used, then all the above described logic only
applies to untagged GRASP packets. For the purpose of ACP neighbor applies to untagged GRASP packets. For the purpose of ACP neighbor
discovery via GRASP, no VLAN tagged packets SHOULD be sent or discovery via GRASP, no VLAN tagged packets SHOULD be sent or
received. In a hybrid L2/L3 switch, each VLAN would therefore only received. In a hybrid L2/L3 switch, each VLAN would therefore only
create ACP adjacencies across those ports where the VLAN is carried create ACP adjacencies across those ports where the VLAN is carried
untagged. untagged.
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explicit configuration. To support connections to adjacent non-ACP explicit configuration. To support connections to adjacent non-ACP
nodes, an ACP node SHOULD support "ACP connect" (sometimes also nodes, an ACP node SHOULD support "ACP connect" (sometimes also
called "autonomic connect"): called "autonomic connect"):
"ACP connect" is an interface level configured workaround for "ACP connect" is an interface level configured workaround for
connection of trusted non-ACP nodes to the ACP. The ACP node on connection of trusted non-ACP nodes to the ACP. The ACP node on
which ACP connect is configured is called an "ACP edge node". With which ACP connect is configured is called an "ACP edge node". With
ACP connect, the ACP is accessible from those non-ACP nodes (such as ACP connect, the ACP is accessible from those non-ACP nodes (such as
NOC systems) on such an interface without those non-ACP nodes having NOC systems) on such an interface without those non-ACP nodes having
to support any ACP discovery or ACP channel setup. This is also to support any ACP discovery or ACP channel setup. This is also
called "native" access to the ACP (native == without ACP secure called "native" access to the ACP because to those NOC systems the
channel) because to those NOC systems the interface looks like a interface looks like a normal network interface without any ACP
normal network interface (without any encryption/novel-signaling). secure channel that is encapsulating the traffic.
Data-Plane "native" (no ACP) Data-Plane "native" (no ACP)
. .
+--------+ +----------------+ . +-------------+ +--------+ +----------------+ . +-------------+
| ACP | |ACP Edge Node | . | | | ACP | |ACP Edge Node | . | |
| Node | | | v | | | Node | | | v | |
| |-------|...[ACP VRF]....+----------------| |+ | |-------|...[ACP VRF]....+----------------| |+
| | ^ |. | | NOC Device || | | ^ |. | | NOC Device ||
| | . | .[Data-Plane]..+----------------| "NMS hosts" || | | . | .[Data-Plane]..+----------------| "NMS hosts" ||
| | . | [ ] | . ^ | || | | . | [ ] | . ^ | ||
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An ACP connect interface provides exclusively access to only the ACP. An ACP connect interface provides exclusively access to only the ACP.
This is likely insufficient for many NMS hosts. Instead, they would This is likely insufficient for many NMS hosts. Instead, they would
require a second "Data-Plane" interface outside the ACP for require a second "Data-Plane" interface outside the ACP for
connections between the NMS host and administrators, or Internet connections between the NMS host and administrators, or Internet
based services, or for direct access to the Data-Plane. The document based services, or for direct access to the Data-Plane. The document
"Using Autonomic Control Plane for Stable Connectivity of Network "Using Autonomic Control Plane for Stable Connectivity of Network
OAM" [RFC8368] explains in more detail how the ACP can be integrated OAM" [RFC8368] explains in more detail how the ACP can be integrated
in a mixed NOC environment. in a mixed NOC environment.
An ACP connect interface SHOULD use an IPv6 address/prefix from the An ACP connect interface SHOULD use an IPv6 address/prefix from the
ACP Manual Addressing Sub-Scheme (Section 6.10.4), letting the ACP Manual Addressing Sub-Scheme (Section 6.11.4), letting the
operator configure for example only the Subnet-ID and having the node operator configure for example only the Subnet-ID and having the node
automatically assign the remaining part of the prefix/address. It automatically assign the remaining part of the prefix/address. It
SHOULD NOT use a prefix that is also routed outside the ACP so that SHOULD NOT use a prefix that is also routed outside the ACP so that
the addresses clearly indicate whether it is used inside the ACP or the addresses clearly indicate whether it is used inside the ACP or
not. not.
The prefix of ACP connect subnets MUST be distributed by the ACP edge The prefix of ACP connect subnets MUST be distributed by the ACP edge
node into the ACP routing protocol RPL. The NMS hosts MUST connect node into the ACP routing protocol RPL. The NMS hosts MUST connect
to prefixes in the ACP routing table via its ACP connect interface. to prefixes in the ACP routing table via its ACP connect interface.
In the simple case where the ACP uses only one ULA prefix and all ACP In the simple case where the ACP uses only one ULA prefix and all ACP
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towards its different interfaces, ACP and Data-Plane. With RFC6724, towards its different interfaces, ACP and Data-Plane. With RFC6724,
The NMS host will select the ACP connect interface for all addresses The NMS host will select the ACP connect interface for all addresses
in the ACP because any ACP destination address is longest matched by in the ACP because any ACP destination address is longest matched by
the address on the ACP connect interface. If the NMS hosts ACP the address on the ACP connect interface. If the NMS hosts ACP
connect interface uses another prefix or if the ACP uses multiple ULA connect interface uses another prefix or if the ACP uses multiple ULA
prefixes, then the NMS hosts require (static) routes towards the ACP prefixes, then the NMS hosts require (static) routes towards the ACP
interface for these prefixes. interface for these prefixes.
When an ACP Edge node receives a packet from an ACP connect When an ACP Edge node receives a packet from an ACP connect
interface, the ACP Edge node MUST only forward the packet into the interface, the ACP Edge node MUST only forward the packet into the
ACP if the packet has an IPv6 source address from that interface. ACP if the packet has an IPv6 source address from that interface
This is sometimes called "RPF filtering". This MAY be changed (this is sometimes called "RPF filtering"). This filtering rule MAY
through administrative measures. be changed through administrative measures. The more any such
administrative action enable reachability of non ACP nodes to the
ACP, the more this may cause security issues.
To limit the security impact of ACP connect, nodes supporting it To limit the security impact of ACP connect, nodes supporting it
SHOULD implement a security mechanism to allow configuration/use of SHOULD implement a security mechanism to allow configuration/use of
ACP connect interfaces only on nodes explicitly targeted to be ACP connect interfaces only on nodes explicitly targeted to be
deployed with it (those in physically secure locations such as a deployed with it (those in physically secure locations such as a
NOC). For example, the registrar could disable the ability to enable NOC). For example, the registrar could disable the ability to enable
ACP connect on devices during enrollment and that property could only ACP connect on devices during enrollment and that property could only
be changed through re-enrollment. See also Appendix A.10.5. be changed through re-enrollment. See also Appendix A.10.5.
ACP Edge nodes SHOULD have a configurable option to prohibit packets ACP Edge nodes SHOULD have a configurable option to prohibit packets
with RPI headers (see Section 6.11.1.13 across an ACP connect with RPI headers (see Section 6.12.1.13 across an ACP connect
interface. These headers are outside the scope of the RPL profile in interface. These headers are outside the scope of the RPL profile in
this specification but may be used in future extensions of this this specification but may be used in future extensions of this
specification. specification.
8.1.2. Software Components 8.1.2. Software Components
The previous section assumed that ACP Edge node and NOC devices are The previous section assumed that ACP Edge node and NOC devices are
separate physical devices and the ACP connect interface is a physical separate physical devices and the ACP connect interface is a physical
network connection. This section discusses the implication when network connection. This section discusses the implication when
these components are instead software components running on a single these components are instead software components running on a single
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- Did the neighbor close the connection on us or did we close the - Did the neighbor close the connection on us or did we close the
connection on it because the domain certificate membership connection on it because the domain certificate membership
failed? failed?
- If the neighbor closed the connection on us, provide any error - If the neighbor closed the connection on us, provide any error
diagnostics from the secure channel protocol. diagnostics from the secure channel protocol.
- If we failed the attempt, display our local reason: - If we failed the attempt, display our local reason:
o There was no common secure channel protocol supported by the o There was no common secure channel protocol supported by the
two neighbors (this could not happen on nodes supporting two neighbors (this could not happen on nodes supporting
this specification because it mandates common support for this specification because it mandates common support for
IPsec). IPsec).
o The ACP certificate membership check (Section 6.1.3) fails: o The ACP certificate membership check (Section 6.2.3) fails:
+ The neighbor's certificate is not signed directly or + The neighbor's certificate is not signed directly or
indirectly by one of the nodes TA. Provide diagnostics indirectly by one of the nodes TA. Provide diagnostics
which TA it has (can identify whom the device belongs which TA it has (can identify whom the device belongs
to). to).
+ The neighbor's certificate does not have the same domain + The neighbor's certificate does not have the same domain
(or no domain at all). Diagnose domain-name and (or no domain at all). Diagnose domain-name and
potentially other cert info. potentially other cert info.
+ The neighbor's certificate has been revoked or could not + The neighbor's certificate has been revoked or could not
be authenticated by OCSP. be authenticated by OCSP.
+ The neighbor's certificate has expired - or is not yet + The neighbor's certificate has expired - or is not yet
valid. valid.
- Any other connection issues in e.g., IKEv2 / IPsec, DTLS?. - Any other connection issues in e.g., IKEv2 / IPsec, DTLS?.
Question: Is the ACP operating correctly across its secure channels? Question: Is the ACP operating correctly across its secure channels?
* Are there one or more active ACP neighbors with secure channels? * Are there one or more active ACP neighbors with secure channels?
* Is the RPL routing protocol for the ACP running? * Is the RPL routing protocol for the ACP running?
* Is there a default route to the root in the ACP routing table? * Is there a default route to the root in the ACP routing table?
* Is there for each direct ACP neighbor not reachable over the ACP * Is there for each direct ACP neighbor not reachable over the ACP
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unsolicited (as it would be in LLDP) so that other observers on the unsolicited (as it would be in LLDP) so that other observers on the
same subnet can determine who is an "interested adjacent party". same subnet can determine who is an "interested adjacent party".
9.1.1. Secure Channel Peer diagnostics 9.1.1. Secure Channel Peer diagnostics
When using mutual certificate authentication, the TA certificate is When using mutual certificate authentication, the TA certificate is
not required to be signalled explicitly because its hash is not required to be signalled explicitly because its hash is
sufficient for certificate chain validation. In the case of ACP sufficient for certificate chain validation. In the case of ACP
secure channel setup this leads to limited diagnostics when secure channel setup this leads to limited diagnostics when
authentication fails because of TA mismatch. For this reason, authentication fails because of TA mismatch. For this reason,
Section 6.7.2 recommends to also include the TA certificate in the Section 6.8.2 recommends to also include the TA certificate in the
secure channel signalling. This should be possible to do without secure channel signalling. This should be possible to do without
protocol modifications in the security association protocols used by protocol modifications in the security association protocols used by
the ACP. For example, while [RFC7296] does not mention this, it also the ACP. For example, while [RFC7296] does not mention this, it also
does not prohibit it. does not prohibit it.
One common deployment use case where the diagnostic through the One common deployment use case where the diagnostic through the
signalled TA of a candidate peer is very helpfull are multi-tenant signalled TA of a candidate peer is very helpfull are multi-tenant
environments such as office buildings, where different tenants run environments such as office buildings, where different tenants run
their own networks and ACPs. Each tenant is given supposedly their own networks and ACPs. Each tenant is given supposedly
disjoint L2 connectivity through the building infrastructure. In disjoint L2 connectivity through the building infrastructure. In
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already aligned so that the ACP domain membership check is only already aligned so that the ACP domain membership check is only
failing on the TA. failing on the TA.
A fourth example case is when multiple registrars where set up for A fourth example case is when multiple registrars where set up for
the same ACP but without correctly setting up the same TA. For the same ACP but without correctly setting up the same TA. For
example when registrars support to also be CA themselves but are example when registrars support to also be CA themselves but are
misconfigured to become TA instead of intermediate CA. misconfigured to become TA instead of intermediate CA.
9.2. ACP Registrars 9.2. ACP Registrars
As described in Section 6.10.7, the ACP addressing mechanism is As described in Section 6.11.7, the ACP addressing mechanism is
designed to enable lightweight, distributed and uncoordinated ACP designed to enable lightweight, distributed and uncoordinated ACP
registrars that are providing ACP address prefixes to candidate ACP registrars that are providing ACP address prefixes to candidate ACP
nodes by enrolling them with an ACP certificate into an ACP domain nodes by enrolling them with an ACP certificate into an ACP domain
via any appropriate mechanism/protocol, automated or not. via any appropriate mechanism/protocol, automated or not.
This section discusses informatively more details and options for ACP This section discusses informatively more details and options for ACP
registrars. registrars.
9.2.1. Registrar interactions 9.2.1. Registrar interactions
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An ACP registrar could operate EST for ACP certificate renewal and/or An ACP registrar could operate EST for ACP certificate renewal and/or
act as a CRL Distribution point. A node performing these services act as a CRL Distribution point. A node performing these services
does not need to support performing (initial) enrollment, but it does does not need to support performing (initial) enrollment, but it does
require the same above described connectivity as an ACP registrar: require the same above described connectivity as an ACP registrar:
via the ACP to ACP nodes and via the Data-Plane to the TA and other via the ACP to ACP nodes and via the Data-Plane to the TA and other
sources of CRL information. sources of CRL information.
9.2.2. Registrar Parameter 9.2.2. Registrar Parameter
The interactions of an ACP registrar outlined Section 6.10.7 and The interactions of an ACP registrar outlined Section 6.11.7 and
Section 9.2.1 above depend on the following parameters: Section 9.2.1 above depend on the following parameters:
* A URL to the TA and credentials so that the ACP registrar can let * A URL to the TA and credentials so that the ACP registrar can let
the TA sign candidate ACP node certificates. the TA sign candidate ACP node certificates.
* The ACP domain-name. * The ACP domain-name.
* The Registrar-ID to use. This could default to a MAC address of * The Registrar-ID to use. This could default to a MAC address of
the ACP registrar. the ACP registrar.
* For recovery, the next-useable Node-IDs for zone (Zone-ID=0) sub- * For recovery, the next-useable Node-IDs for zone (Zone-ID=0) sub-
addressing scheme, for Vlong /112 and for Vlong /120 sub- addressing scheme, for Vlong /112 and for Vlong /120 sub-
addressing scheme. These IDs would only need to be provisioned addressing scheme. These IDs would only need to be provisioned
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DULL GRAP. The interface level configuration option "ANI enable" on DULL GRAP. The interface level configuration option "ANI enable" on
nodes supporting BRSKI and ACP starts with BRSKI pledge operations nodes supporting BRSKI and ACP starts with BRSKI pledge operations
when there is no domain certificate on the node. On ACP/BRSKI nodes, when there is no domain certificate on the node. On ACP/BRSKI nodes,
"ACP enable" may not need to be supported, but only "ANI enable". "ACP enable" may not need to be supported, but only "ANI enable".
Unless overridden by global configuration options (see later), "ACP/ Unless overridden by global configuration options (see later), "ACP/
ANI enable" will result in "down" state on an interface to behave as ANI enable" will result in "down" state on an interface to behave as
"admin down". "admin down".
9.3.4. Which interfaces to auto-enable? 9.3.4. Which interfaces to auto-enable?
(Section 6.3) requires that "ACP enable" is automatically set on (Section 6.4) requires that "ACP enable" is automatically set on
native interfaces, but not on non-native interfaces (reminder: a native interfaces, but not on non-native interfaces (reminder: a
native interface is one that exists without operator configuration native interface is one that exists without operator configuration
action such as physical interfaces in physical devices). action such as physical interfaces in physical devices).
Ideally, ACP enable is set automatically on all interfaces that Ideally, ACP enable is set automatically on all interfaces that
provide access to additional connectivity that allows to reach more provide access to additional connectivity that allows to reach more
nodes of the ACP domain. The best set of interfaces necessary to nodes of the ACP domain. The best set of interfaces necessary to
achieve this is not possible to determine automatically. Native achieve this is not possible to determine automatically. Native
interfaces are the best automatic approximation. interfaces are the best automatic approximation.
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It is enabled by default on native interfaces and has to be It is enabled by default on native interfaces and has to be
configured explicitly on other interfaces. configured explicitly on other interfaces.
Disabling "ACP/ANI enable" global and per-interface should have Disabling "ACP/ANI enable" global and per-interface should have
additional checks to minimize undesired breakage of ACP. The degree additional checks to minimize undesired breakage of ACP. The degree
of control could be a domain wide parameter in the domain of control could be a domain wide parameter in the domain
certificates. certificates.
9.4. Partial or Incremental adoption 9.4. Partial or Incremental adoption
The ACP Zone Addressing Sub-Scheme (see Section 6.10.3) allows The ACP Zone Addressing Sub-Scheme (see Section 6.11.3) allows
incremental adoption of the ACP in a network where ACP can be incremental adoption of the ACP in a network where ACP can be
deployed on edge areas, but not across the core that is connecting deployed on edge areas, but not across the core that is connecting
those edges. those edges.
In such a setup, each edge network, such as a branch or campus of an In such a setup, each edge network, such as a branch or campus of an
enterprise network has a disjoined ACP to which one or more unique enterprise network has a disjoined ACP to which one or more unique
Zone-IDs are assigned: ACP nodes registered for a specific ACP zone Zone-IDs are assigned: ACP nodes registered for a specific ACP zone
have to receive ACP Zone Addressing Sub-scheme addresses, for example have to receive ACP Zone Addressing Sub-scheme addresses, for example
by virtue of configuring for each such zone one or more ACP by virtue of configuring for each such zone one or more ACP
Registrars with that Zone-ID. All the Registrars for these ACP Zones Registrars with that Zone-ID. All the Registrars for these ACP Zones
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YANG ([RFC7950]) data models. YANG ([RFC7950]) data models.
The most important examples of such configuration include: The most important examples of such configuration include:
* When ACP nodes do not support an autonomic way to receive an ACP * When ACP nodes do not support an autonomic way to receive an ACP
certificate, for example BRSKI, then such certificate needs to be certificate, for example BRSKI, then such certificate needs to be
configured via some pre-existing mechanisms outside the scope of configured via some pre-existing mechanisms outside the scope of
this specification. Today, router have typically a variety of this specification. Today, router have typically a variety of
mechanisms to do this. mechanisms to do this.
* Certificate maintenance requires PKI functions. Discovery of * Certificate maintenance requires PKI functions. Discovery of
these functions across the ACP is automated (see Section 6.1.5), these functions across the ACP is automated (see Section 6.2.5),
but their configuration is not. but their configuration is not.
* When non-ACP capable nodes such as pre-existing NMS need to be * When non-ACP capable nodes such as pre-existing NMS need to be
physically connected to the ACP, the ACP node to which they attach physically connected to the ACP, the ACP node to which they attach
needs to be configured with ACP-connect according to Section 8.1. needs to be configured with ACP-connect according to Section 8.1.
It is also possible to use that single physical connection to It is also possible to use that single physical connection to
connect both to ACP and the Data-Plane of the network as explained connect both to ACP and the Data-Plane of the network as explained
in Section 8.1.4. in Section 8.1.4.
* When devices are not autonomically bootstrapped, explicit * When devices are not autonomically bootstrapped, explicit
configuration to enable the ACP needs to be applied. See configuration to enable the ACP needs to be applied. See
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After a network partition, a re-merge will just establish the After a network partition, a re-merge will just establish the
previous status, certificates can be renewed, the CRL is available, previous status, certificates can be renewed, the CRL is available,
and new nodes can be enrolled everywhere. Since all nodes use the and new nodes can be enrolled everywhere. Since all nodes use the
same TA, a re-merge will be smooth. same TA, a re-merge will be smooth.
Merging two networks with different TA requires the ACP nodes to Merging two networks with different TA requires the ACP nodes to
trust the union of TA. As long as the routing-subdomain hashes are trust the union of TA. As long as the routing-subdomain hashes are
different, the addressing will not overlap. Accidentally, overlaps different, the addressing will not overlap. Accidentally, overlaps
will only happen in the unlikely event of a 40-bit hash collision in will only happen in the unlikely event of a 40-bit hash collision in
SHA256 (see Section 6.10). Note that the complete mechanisms to SHA256 (see Section 6.11). Note that the complete mechanisms to
merge networks is out of scope of this specification. merge networks is out of scope of this specification.
It is also highly desirable for implementation of the ACP to be able It is also highly desirable for implementation of the ACP to be able
to run it over interfaces that are administratively down. If this is to run it over interfaces that are administratively down. If this is
not feasible, then it might instead be possible to request explicit not feasible, then it might instead be possible to request explicit
operator override upon administrative actions that would operator override upon administrative actions that would
administratively bring down an interface across which the ACP is administratively bring down an interface across which the ACP is
running. Especially if bringing down the ACP is known to disconnect running. Especially if bringing down the ACP is known to disconnect
the operator from the node. For example any such down administrative the operator from the node. For example any such down administrative
action could perform a dependency check to see if the transport action could perform a dependency check to see if the transport
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However, the security of the ACP depends on a number of other However, the security of the ACP depends on a number of other
factors: factors:
* The usage of domain certificates depends on a valid supporting PKI * The usage of domain certificates depends on a valid supporting PKI
infrastructure. If the chain of trust of this PKI infrastructure infrastructure. If the chain of trust of this PKI infrastructure
is compromised, the security of the ACP is also compromised. This is compromised, the security of the ACP is also compromised. This
is typically under the control of the network administrator. is typically under the control of the network administrator.
* ACP nodes receive their certificates from ACP registrars. These * ACP nodes receive their certificates from ACP registrars. These
ACP registrars are security critical dependencies of the ACP: ACP registrars are security critical dependencies of the ACP:
Procedures and protocols for ACP registrars are outside the scope Procedures and protocols for ACP registrars are outside the scope
of this specification as explained in Section 6.10.7.1, only of this specification as explained in Section 6.11.7.1, only
requirements against the resulting ACP certificates are specified. requirements against the resulting ACP certificates are specified.
* Every ACP registrar (for enrollment of ACP certificates) and ACP * Every ACP registrar (for enrollment of ACP certificates) and ACP
EST server (for renewal of ACP certificates) is a security EST server (for renewal of ACP certificates) is a security
critical entity and its protocols are security critical protocols. critical entity and its protocols are security critical protocols.
Both need to be hardened against attacks, similar to a CA and its Both need to be hardened against attacks, similar to a CA and its
protocols. A malicious registrar can enroll malicious nodes to an protocols. A malicious registrar can enroll malicious nodes to an
ACP network (if the CA delegates this policy to the registrar) or ACP network (if the CA delegates this policy to the registrar) or
break ACP routing for example by assigning duplicate ACP address break ACP routing for example by assigning duplicate ACP address
assignment to ACP nodes via their ACP certificates. assignment to ACP nodes via their ACP certificates.
* ACP nodes that are ANI nodes rely on BRSKI as the protocol for ACP * ACP nodes that are ANI nodes rely on BRSKI as the protocol for ACP
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In summary, attacks against the PKI/certificate dependencies of the In summary, attacks against the PKI/certificate dependencies of the
ACP can be minimized by a variety of hardware/software commponents ACP can be minimized by a variety of hardware/software commponents
including options such as TPM for IDevID/ACP-certificate, including options such as TPM for IDevID/ACP-certificate,
prohibitions against execution of non-trusted software and design prohibitions against execution of non-trusted software and design
aspects of the EST Server functionality for the ACP to eliminate aspects of the EST Server functionality for the ACP to eliminate
configuration level impairment. configuration level impairment.
Because ACP peers select one out of potentially more than one Because ACP peers select one out of potentially more than one
mutually supported ACP secure channel protocols via the approach mutually supported ACP secure channel protocols via the approach
described in Section 6.5, ACP secure channel setup is subject to described in Section 6.6, ACP secure channel setup is subject to
downgrade attacks by MITM attackers. This can be discovered by downgrade attacks by MITM attackers. This can be discovered by
additional mechanisms described in Appendix A.10.9. additional mechanisms described in Appendix A.10.9.
The security model of the ACP as defined in this document is tailored The security model of the ACP as defined in this document is tailored
for use with private PKI. The TA of a private PKI provide the for use with private PKI. The TA of a private PKI provide the
security against maliciously created ACP certificates to give access security against maliciously created ACP certificates to give access
to an ACP. Such attacks can create fake ACP certificates with to an ACP. Such attacks can create fake ACP certificates with
correct looking AcpNodeNames, but those certificates would not pass correct looking AcpNodeNames, but those certificates would not pass
the certificate path validation of the ACP domain membership check the certificate path validation of the ACP domain membership check
(see Section 6.1.3, point 2). (see Section 6.2.3, point 2).
If public CA are to be used, ACP registrars would need to prove If public CA are to be used, ACP registrars would need to prove
ownership of the domain-name of AcpNodeNames to the public CA. ownership of the domain-name of AcpNodeNames to the public CA.
However, maintaining the ULA based address allocation when using a However, maintaining the ULA based address allocation when using a
public CA might be considered to be a violation of the private public CA might be considered to be a violation of the private
allocation expectation of ULA prefixes. To avoid this issue, further allocation expectation of ULA prefixes. To avoid this issue, further
changes to registrar address allocation procedures might be needed, changes to registrar address allocation procedures might be needed,
for example using global IPv6 address prefixes owned by the public CA for example using global IPv6 address prefixes owned by the public CA
instead of ULA. instead of ULA.
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the network nodes. By using the ACP, most of the issues of the network nodes. By using the ACP, most of the issues of
configuration/provisioning caused loss of connectivity for remote configuration/provisioning caused loss of connectivity for remote
provisioning/configuration will be eliminated, see Section 6. Only provisioning/configuration will be eliminated, see Section 6. Only
few exceptions such as explicit physical interface down configuration few exceptions such as explicit physical interface down configuration
will be left Section 9.3.2. will be left Section 9.3.2.
Many details of ACP are designed with security in mind and discussed Many details of ACP are designed with security in mind and discussed
elsewhere in the document: elsewhere in the document:
IPv6 addresses used by nodes in the ACP are covered as part of the IPv6 addresses used by nodes in the ACP are covered as part of the
node's domain certificate as described in Section 6.1.2. This allows node's domain certificate as described in Section 6.2.2. This allows
even verification of ownership of a peer's IPv6 address when using a even verification of ownership of a peer's IPv6 address when using a
connection authenticated with the domain certificate. connection authenticated with the domain certificate.
The ACP acts as a security (and transport) substrate for GRASP inside The ACP acts as a security (and transport) substrate for GRASP inside
the ACP such that GRASP is not only protected by attacks from the the ACP such that GRASP is not only protected by attacks from the
outside, but also by attacks from compromised inside attackers - by outside, but also by attacks from compromised inside attackers - by
relying not only on hop-by-hop security of ACP secure channels, but relying not only on hop-by-hop security of ACP secure channels, but
adding end-to-end security for those GRASP messages. See adding end-to-end security for those GRASP messages. See
Section 6.8.2. Section 6.9.2.
ACP provides for secure, resilient zero-touch discovery of EST ACP provides for secure, resilient zero-touch discovery of EST
servers for certificate renewal. See Section 6.1.5. servers for certificate renewal. See Section 6.2.5.
ACP provides extensible, auto-configuring hop-by-hop protection of ACP provides extensible, auto-configuring hop-by-hop protection of
the ACP infrastructure via the negotiation of hop-by-hop secure the ACP infrastructure via the negotiation of hop-by-hop secure
channel protocols. See Section 6.5. channel protocols. See Section 6.6.
The ACP is designed to minimize attacks from the outside by The ACP is designed to minimize attacks from the outside by
minimizing its dependency against any non-ACP (Data-Plane) minimizing its dependency against any non-ACP (Data-Plane)
operations/configuration on a node. See also Section 6.12.2. operations/configuration on a node. See also Section 6.13.2.
In combination with BRSKI, ACP enables a resilient, fully zero-touch In combination with BRSKI, ACP enables a resilient, fully zero-touch
network solution for short-lived certificates that can be renewed or network solution for short-lived certificates that can be renewed or
re-enrolled even after unintentional expiry (e.g., because of re-enrolled even after unintentional expiry (e.g., because of
interrupted connectivity). See Appendix A.2. interrupted connectivity). See Appendix A.2.
Because ACP secure channels can be long lived, but certificates used Because ACP secure channels can be long lived, but certificates used
may be short lived, secure channels, for example built via IPsec need may be short lived, secure channels, for example built via IPsec need
to be terminated when peer certificates expire. See Section 6.7.5. to be terminated when peer certificates expire. See Section 6.8.5.
Section 7.2 describes how to implement a routed ACP topology Section 7.2 describes how to implement a routed ACP topology
operating on what effectively is a large bridge-domain when using L3/ operating on what effectively is a large bridge-domain when using L3/
L2 routers that operate at L2 in the Data-Plane. In this case, the L2 routers that operate at L2 in the Data-Plane. In this case, the
ACP is subject to much higher likelyhood of attacks by other nodes ACP is subject to much higher likelyhood of attacks by other nodes
"stealing" L2 addresses than in the actual routed case. Especially "stealing" L2 addresses than in the actual routed case. Especially
when the bridged network includes non-trusted devices such as hosts. when the bridged network includes non-trusted devices such as hosts.
This is a generic issue in L2 LANs. L2/L3 devices often already have This is a generic issue in L2 LANs. L2/L3 devices often already have
some form of "port security" to prohibit this. They rely on NDP or some form of "port security" to prohibit this. They rely on NDP or
DHCP learning of which port/MAC-address and IPv6 address belong DHCP learning of which port/MAC-address and IPv6 address belong
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For the ANIMA-ACP-2020 ASN.1 module, IANA is asked to register value For the ANIMA-ACP-2020 ASN.1 module, IANA is asked to register value
IANA1 for "id-mod-anima-acpnodename-2020" in the "SMI Security for IANA1 for "id-mod-anima-acpnodename-2020" in the "SMI Security for
PKIX Module Identifier" (1.3.6.1.5.5.7.0) registry. PKIX Module Identifier" (1.3.6.1.5.5.7.0) registry.
For the otherName / AcpNodeName, IANA is asked to register a value For the otherName / AcpNodeName, IANA is asked to register a value
for IANA2 for id-on-AcpNodeName in the "SMI Security for PKIX Other for IANA2 for id-on-AcpNodeName in the "SMI Security for PKIX Other
Name Forms" (1.3.6.1.5.5.7.8) registry. Name Forms" (1.3.6.1.5.5.7.8) registry.
The IANA is requested to register the value "AN_ACP" (without quotes) The IANA is requested to register the value "AN_ACP" (without quotes)
to the GRASP Objectives Names Table in the GRASP Parameter Registry. to the GRASP Objectives Names Table in the GRASP Parameter Registry.
The specification for this value is this document, Section 6.3. The specification for this value is this document, Section 6.4.
The IANA is requested to register the value "SRV.est" (without The IANA is requested to register the value "SRV.est" (without
quotes) to the GRASP Objectives Names Table in the GRASP Parameter quotes) to the GRASP Objectives Names Table in the GRASP Parameter
Registry. The specification for this value is this document, Registry. The specification for this value is this document,
Section 6.1.5. Section 6.2.5.
Explanation: This document chooses the initially strange looking Explanation: This document chooses the initially strange looking
format "SRV.<service-name>" because these objective names would be in format "SRV.<service-name>" because these objective names would be in
line with potential future simplification of the GRASP objective line with potential future simplification of the GRASP objective
registry. Today, every name in the GRASP objective registry needs to registry. Today, every name in the GRASP objective registry needs to
be explicitly allocated with IANA. In the future, this type of be explicitly allocated with IANA. In the future, this type of
objective names could considered to be automatically registered in objective names could considered to be automatically registered in
that registry for the same service for which <service-name> is that registry for the same service for which <service-name> is
registered according to [RFC6335]. This explanation is solely registered according to [RFC6335]. This explanation is solely
informational and has no impact on the requested registration. informational and has no impact on the requested registration.
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The IANA is requested to create an ACP Parameter Registry with The IANA is requested to create an ACP Parameter Registry with
currently one registry table - the "ACP Address Type" table. currently one registry table - the "ACP Address Type" table.
"ACP Address Type" Table. The value in this table are numeric values "ACP Address Type" Table. The value in this table are numeric values
0...3 paired with a name (string). Future values MUST be assigned 0...3 paired with a name (string). Future values MUST be assigned
using the Standards Action policy defined by [RFC8126]. The using the Standards Action policy defined by [RFC8126]. The
following initial values are assigned by this document: following initial values are assigned by this document:
0: ACP Zone Addressing Sub-Scheme (ACP RFC 1: ACP Vlong Addressing 0: ACP Zone Addressing Sub-Scheme (ACP RFC 1: ACP Vlong Addressing
Sub-Scheme (ACP RFC Figure 12) / ACP Manual Addressing Sub-Scheme Sub-Scheme (ACP RFC Figure 12) / ACP Manual Addressing Sub-Scheme
(ACP RFC Section 6.10.4) Section 6.10.5) (ACP RFC Section 6.11.4) Section 6.11.5)
13. Acknowledgements 13. Acknowledgements
This work originated from an Autonomic Networking project at Cisco This work originated from an Autonomic Networking project at Cisco
Systems, which started in early 2010. Many people contributed to Systems, which started in early 2010. Many people contributed to
this project and the idea of the Autonomic Control Plane, amongst this project and the idea of the Autonomic Control Plane, amongst
which (in alphabetical order): Ignas Bagdonas, Parag Bhide, Balaji which (in alphabetical order): Ignas Bagdonas, Parag Bhide, Balaji
BL, Alex Clemm, Yves Hertoghs, Bruno Klauser, Max Pritikin, Michael BL, Alex Clemm, Yves Hertoghs, Bruno Klauser, Max Pritikin, Michael
Richardson, Ravi Kumar Vadapalli. Richardson, Ravi Kumar Vadapalli.
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A. (new) Moved all explanations and discussions about futures from A. (new) Moved all explanations and discussions about futures from
section 10 into this new appendix. This text should not be removed section 10 into this new appendix. This text should not be removed
because it captures a lot of repeated asked questions in WG and because it captures a lot of repeated asked questions in WG and
during reviews and from users, and also captures ideas for some during reviews and from users, and also captures ideas for some
likely important followup work. But none of this is relevant to likely important followup work. But none of this is relevant to
implementing (section 6) and operating (section 10) the ACP. implementing (section 6) and operating (section 10) the ACP.
15.2. draft-ietf-anima-autonomic-control-plane-29 15.2. draft-ietf-anima-autonomic-control-plane-29
Discuss from Ben Kaduk: Discuss/Comments from Barry Leiba:
Various editorial nits - thanks.
6.1 New section pulling in TLS requirements, no need anymore to
duplicat for ACP GRASP, EST, BRSKI (ACP/ANI nodes) and (if desired)
OCSP/CRLDP. Added rule to start use secure channel only after
negotiation has finished. Added rules not to optimize negotiation
across multiple L2 interfaces to the same peer.
6.6 Changed role names in secure channel negotiation process: Alice/
Bob -> Decider/Follower. Explanation enhancements. Added definition
for ACP nodes with "0" address.
6.8.3 Improved explanation how IKEv2 forces preference of IPsec over
GRE due to ACP IPsec profiles being Tunneled vs. Transport.
6.8.4 Limited mentioning of DTLS version requirements to this
section.
6.9.2 Removed TLS requirements, they are now in 6.1.
6.10.6 Removed explanation of IANA allocation requirement. Redundant
- already in IANA section, and was seen as confusing.
8.1.1 Clarified that there can be security impacts when weakening
directly connected address RPF filtering for ACP connect interfaces.
Discuss/Comments from Ben Kaduk:
Many good editorial improvements - thanks!. Many good editorial improvements - thanks!.
5. added explanation of what to do upon failed secure channel 5. added explanation of what to do upon failed secure channel
establishment. establishment.
6.1.1. refined/extended cert public cey crypto algo and better 6.1.1. refined/extended cert public cey crypto algo and better
distinguished algo for the keys of the cert and the key of the distinguished algo for the keys of the cert and the key of the
signer. signer.
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about aspects of the normative parts of this document or associated about aspects of the normative parts of this document or associated
mechanisms such as BRSKI (such as why specific choices were made by mechanisms such as BRSKI (such as why specific choices were made by
the ACP) and they provide discussion about possible future variations the ACP) and they provide discussion about possible future variations
of the ACP. of the ACP.
A.1. ACP Address Space Schemes A.1. ACP Address Space Schemes
This document defines the Zone, Vlong and Manual sub address schemes This document defines the Zone, Vlong and Manual sub address schemes
primarily to support address prefix assignment via distributed, primarily to support address prefix assignment via distributed,
potentially uncoordinated ACP registrars as defined in potentially uncoordinated ACP registrars as defined in
Section 6.10.7. This costs 48/46-bit identifier so that these ACP Section 6.11.7. This costs 48/46-bit identifier so that these ACP
registrar can assign non-conflicting address prefixes. This design registrar can assign non-conflicting address prefixes. This design
does not leave enough bits to simultaneously support a large number does not leave enough bits to simultaneously support a large number
of nodes (Node-ID) plus a large prefix of local addresses for every of nodes (Node-ID) plus a large prefix of local addresses for every
node plus a large enough set of bits to identify a routing Zone. In node plus a large enough set of bits to identify a routing Zone. In
result, Zone, Vlong 8/16 attempt to support all features, but in via result, Zone, Vlong 8/16 attempt to support all features, but in via
separate prefixes. separate prefixes.
In networks that always expect to rely on a centralized PMS as In networks that always expect to rely on a centralized PMS as
described above (Section 9.2.5), the 48/46-bits for the Registrar-ID described above (Section 9.2.5), the 48/46-bits for the Registrar-ID
could be saved. Such variations of the ACP addressing mechanisms could be saved. Such variations of the ACP addressing mechanisms
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mechanism would not work easily for GRASP M_DISCOVERY messages which mechanism would not work easily for GRASP M_DISCOVERY messages which
are intelligently (constrained) flooded not across the whole ACP, but are intelligently (constrained) flooded not across the whole ACP, but
only up to a node where a responder is found. We do expect that many only up to a node where a responder is found. We do expect that many
future services in ASA will have only few consuming ASA, and for future services in ASA will have only few consuming ASA, and for
those cases, M_DISCOVERY is the more efficient method than flooding those cases, M_DISCOVERY is the more efficient method than flooding
across the whole domain. across the whole domain.
Because the ACP uses RPL, one desirable future extension is to use Because the ACP uses RPL, one desirable future extension is to use
RPLs existing notion of DODAG, which are loop-free distribution RPLs existing notion of DODAG, which are loop-free distribution
trees, to make GRASP flooding more efficient both for M_FLOOD and trees, to make GRASP flooding more efficient both for M_FLOOD and
M_DISCOVERY. See Section 6.12.5 how this will be specifically M_DISCOVERY. See Section 6.13.5 how this will be specifically
beneficial when using NBMA interfaces. This is not currently beneficial when using NBMA interfaces. This is not currently
specified in this document because it is not quite clear yet what specified in this document because it is not quite clear yet what
exactly the implications are to make GRASP flooding depend on RPL exactly the implications are to make GRASP flooding depend on RPL
DODAG convergence and how difficult it would be to let GRASP flooding DODAG convergence and how difficult it would be to let GRASP flooding
access the DODAG information. access the DODAG information.
A.6. Extending ACP channel negotiation (via GRASP) A.6. Extending ACP channel negotiation (via GRASP)
[RFC Editor: This section to be removed before RFC. [RFC Editor: This section to be removed before RFC.
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support multiple different ACP secure channel protocols without a support multiple different ACP secure channel protocols without a
single network wide MTI protocol is important to allow extending single network wide MTI protocol is important to allow extending
secure ACP channel protocols beyond what is specified in this secure ACP channel protocols beyond what is specified in this
document, but it will run into problem if it would be used for document, but it will run into problem if it would be used for
multiple protocols: multiple protocols:
The need to potentially have multiple of these security associations The need to potentially have multiple of these security associations
even temporarily run in parallel to determine which of them works even temporarily run in parallel to determine which of them works
best does not support the most lightweight implementation options. best does not support the most lightweight implementation options.
The simple policy of letting one side (Alice) decide what is best may The simple policy of letting one side (the Decider) decide what is
not lead to the mutual best result. best may not lead to the mutual best result.
The two limitations can easier be solved if the solution was more The two limitations can easier be solved if the solution was more
modular and as few as possible initial secure channel negotiation modular and as few as possible initial secure channel negotiation
protocols would be used, and these protocols would then take on the protocols would be used, and these protocols would then take on the
responsibility to support more flexible objectives to negotiate the responsibility to support more flexible objectives to negotiate the
mutually preferred ACP security channel protocol. mutually preferred ACP security channel protocol.
IKEv2 is the IETF standard protocol to negotiate network security IKEv2 is the IETF standard protocol to negotiate network security
associations. It is meant to be extensible, but it is unclear associations. It is meant to be extensible, but it is unclear
whether it would be feasible to extend IKEv2 to support possible whether it would be feasible to extend IKEv2 to support possible
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A more modular alternative to extending IKEv2 could be to layer a A more modular alternative to extending IKEv2 could be to layer a
modular negotiation mechanism on top of the multitude of existing or modular negotiation mechanism on top of the multitude of existing or
possible future secure channel protocols. For this, GRASP over TLS possible future secure channel protocols. For this, GRASP over TLS
could be considered as a first ACP secure channel negotiation could be considered as a first ACP secure channel negotiation
protocol. The following are initial considerations for such an protocol. The following are initial considerations for such an
approach. A full specification is subject to a separate document: approach. A full specification is subject to a separate document:
To explicitly allow negotiation of the ACP channel protocol, GRASP To explicitly allow negotiation of the ACP channel protocol, GRASP
over a TLS connection using the GRASP_LISTEN_PORT and the node's and over a TLS connection using the GRASP_LISTEN_PORT and the node's and
peer's link-local IPv6 address is used. When Alice and Bob support peer's link-local IPv6 address is used. When both peers support
GRASP negotiation, they do prefer it over any other non-explicitly GRASP negotiation, they do prefer it over any other non-explicitly
negotiated security association protocol and should wait trying any negotiated security association protocol and should wait trying any
non-negotiated ACP channel protocol until after it is clear that non-negotiated ACP channel protocol until after it is clear that
GRASP/TLS will not work to the peer. GRASP/TLS will not work to the peer.
When Alice and Bob successfully establish the GRASP/TSL session, they When the two peers successfully establish the GRASP/TSL session, they
will negotiate the channel mechanism to use using objectives such as will negotiate the channel mechanism to use using objectives such as
performance and perceived quality of the security. After agreeing on performance and perceived quality of the security. After agreeing on
a channel mechanism, Alice and Bob start the selected Channel a channel mechanism, they start the selected Channel protocol steps
protocol. Once the secure channel protocol is successfully running, via appropriate GRASP messages. Once the secure channel protocol is
the GRASP/TLS connection can be kept alive or timed out as long as successfully running, the GRASP/TLS connection can be kept alive or
the selected channel protocol has a secure association between Alice timed out as long as the selected channel protocol has a secure
and Bob. When it terminates, it needs to be re-negotiated via GRASP/ association between the two peers. When it terminates, it needs to
TLS. be re-negotiated via GRASP/TLS.
Notes: Notes:
* Negotiation of a channel type may require IANA assignments of code * Negotiation of a channel type may require IANA assignments of code
points. points.
* TLS is subject to reset attacks, which IKEv2 is not. Normally, * TLS is subject to reset attacks, which IKEv2 is not. Normally,
ACP connections (as specified in this document) will be over link- ACP connections (as specified in this document) will be over link-
local addresses so the attack surface for this one issue in TCP local addresses so the attack surface for this one issue in TCP
should be reduced (note that this may not be true when ACP is should be reduced (note that this may not be true when ACP is
tunneled as described in Section 8.2.2. tunneled as described in Section 8.2.2.
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A.7. CAs, domains and routing subdomains A.7. CAs, domains and routing subdomains
There is a wide range of setting up different ACP solution by There is a wide range of setting up different ACP solution by
appropriately using CAs and the domain and rsub elements in the acp- appropriately using CAs and the domain and rsub elements in the acp-
node-name in the domain certificate. We summarize these options here node-name in the domain certificate. We summarize these options here
as they have been explained in different parts of the document in as they have been explained in different parts of the document in
before and discuss possible and desirable extensions: before and discuss possible and desirable extensions:
An ACP domain is the set of all ACP nodes that can authenticate each An ACP domain is the set of all ACP nodes that can authenticate each
other as belonging to the same ACP network using the ACP domain other as belonging to the same ACP network using the ACP domain
membership check (Section 6.1.3). GRASP inside the ACP is run across membership check (Section 6.2.3). GRASP inside the ACP is run across
all transitively connected ACP nodes in a domain. all transitively connected ACP nodes in a domain.
The rsub element in the acp-node-name permits the use of addresses The rsub element in the acp-node-name permits the use of addresses
from different ULA prefixes. One use case is to create multiple from different ULA prefixes. One use case is to create multiple
physical networks that initially may be separated with one ACP domain physical networks that initially may be separated with one ACP domain
but different routing subdomains, so that all nodes can mutual trust but different routing subdomains, so that all nodes can mutual trust
their ACP certificates (not depending on rsub) and so that they could their ACP certificates (not depending on rsub) and so that they could
connect later together into a contiguous ACP network. connect later together into a contiguous ACP network.
One instance of such a use case is an ACP for regions interconnected One instance of such a use case is an ACP for regions interconnected
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For example, Intent could indicate the desire to build an ACP across For example, Intent could indicate the desire to build an ACP across
all domains that have a common parent domain (without relying on the all domains that have a common parent domain (without relying on the
rsub/routing-subdomain solution defined in this document). For rsub/routing-subdomain solution defined in this document). For
example ACP nodes with domain "example.com", "access.example.com", example ACP nodes with domain "example.com", "access.example.com",
"core.example.com" and "city.core.example.com" should all establish "core.example.com" and "city.core.example.com" should all establish
one single ACP. one single ACP.
If each domain has its own source of Intent, then the Intent would If each domain has its own source of Intent, then the Intent would
simply have to allow adding the peer domains TA and domain names to simply have to allow adding the peer domains TA and domain names to
the parameters for the ACP domain membership check (Section 6.1.3) so the parameters for the ACP domain membership check (Section 6.2.3) so
that nodes from those other domains are accepted as ACP peers. that nodes from those other domains are accepted as ACP peers.
If this Intent was to be originated only from one domain, it could If this Intent was to be originated only from one domain, it could
likely not be made to work because the other domains will not build likely not be made to work because the other domains will not build
any ACP connection amongst each other, whether they use the same or any ACP connection amongst each other, whether they use the same or
different CA due to the ACP domain membership check. different CA due to the ACP domain membership check.
If the domains use the same CA one could change the ACP setup to If the domains use the same CA one could change the ACP setup to
permit for the ACP to be established between two ACP nodes with permit for the ACP to be established between two ACP nodes with
different acp-domain-names, but only for the purpose of disseminating different acp-domain-names, but only for the purpose of disseminating
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prefix from the AN domain name. prefix from the AN domain name.
Some solutions may already have an auto-addressing scheme, for Some solutions may already have an auto-addressing scheme, for
example derived from existing unique device identifiers (e.g., MAC example derived from existing unique device identifiers (e.g., MAC
addresses). In those cases it may not be desirable to assign addresses). In those cases it may not be desirable to assign
addresses to devices via the ACP address information field in the way addresses to devices via the ACP address information field in the way
described in this document. The certificate may simply serve to described in this document. The certificate may simply serve to
identify the ACP domain, and the address field could be omitted. The identify the ACP domain, and the address field could be omitted. The
only fix required in the remaining way the ACP operate is to define only fix required in the remaining way the ACP operate is to define
another element in the domain certificate for the two peers to decide another element in the domain certificate for the two peers to decide
who is Alice and who is Bob during secure channel building. Note who is the Decider and who is the Follower during secure channel
though that future work may leverage the acp address to authenticate building. Note though that future work may leverage the acp address
"ownership" of the address by the device. If the address used by a to authenticate "ownership" of the address by the device. If the
device is derived from some pre-existing permanent local ID (such as address used by a device is derived from some pre-existing permanent
MAC address), then it would be useful to store that address in the local ID (such as MAC address), then it would be useful to store that
certificate using the format of the access address information field address in the certificate using the format of the access address
or in a similar way. information field or in a similar way.
The ACP is defined as a separate VRF because it intends to support The ACP is defined as a separate VRF because it intends to support
well managed networks with a wide variety of configurations. well managed networks with a wide variety of configurations.
Therefore, reliable, configuration-indestructible connectivity cannot Therefore, reliable, configuration-indestructible connectivity cannot
be achieved from the Data-Plane itself. In solutions where all be achieved from the Data-Plane itself. In solutions where all
transit connectivity impacting functions are fully automated transit connectivity impacting functions are fully automated
(including security), indestructible and resilient, it would be (including security), indestructible and resilient, it would be
possible to eliminate the need for the ACP to be a separate VRF. possible to eliminate the need for the ACP to be a separate VRF.
Consider the most simple example system in which there is no separate Consider the most simple example system in which there is no separate
Data-Plane, but the ACP is the Data-Plane. Add BRSKI, and it becomes Data-Plane, but the ACP is the Data-Plane. Add BRSKI, and it becomes
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Automatic assignment of Zone-ID and auto-aggregation of routes could Automatic assignment of Zone-ID and auto-aggregation of routes could
be achieved for example by configuring zone-boundaries, announcing be achieved for example by configuring zone-boundaries, announcing
via GRASP into the zones the zone parameters (zone-ID and /48 ULA via GRASP into the zones the zone parameters (zone-ID and /48 ULA
prefix) and auto-aggegating routes on the zone-boundaries. Nodes prefix) and auto-aggegating routes on the zone-boundaries. Nodes
would assign their Zone-ID and potentially even /48 prefix based on would assign their Zone-ID and potentially even /48 prefix based on
the GRASP announcements. the GRASP announcements.
A.10.2. More options for avoiding IPv6 Data-Plane dependencies A.10.2. More options for avoiding IPv6 Data-Plane dependencies
As described in Section 6.12.2, the ACP depends on the Data-Plane to As described in Section 6.13.2, the ACP depends on the Data-Plane to
establish IPv6 link-local addressing on interfaces. Using a separate establish IPv6 link-local addressing on interfaces. Using a separate
MAC address for the ACP allows to fully isolate the ACP from the MAC address for the ACP allows to fully isolate the ACP from the
Data-Plane in a way that is compatible with this specification. It Data-Plane in a way that is compatible with this specification. It
is also an ideal option when using Single-root input/output is also an ideal option when using Single-root input/output
virtualization (SR-IOV - see https://en.wikipedia.org/wiki/Single- virtualization (SR-IOV - see https://en.wikipedia.org/wiki/Single-
root_input/output_virtualization) in an implementation to isolate the root_input/output_virtualization) in an implementation to isolate the
ACP because different SR-IOV interfaces use different MAC addresses. ACP because different SR-IOV interfaces use different MAC addresses.
When additional MAC address(es) are not available, separation of the When additional MAC address(es) are not available, separation of the
ACP could be done at different demux points. The same subnet ACP could be done at different demux points. The same subnet
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Note that in the case of ANI nodes, all the above considerations Note that in the case of ANI nodes, all the above considerations
equally apply to the encapsulation of BRSKI packets including GRASP equally apply to the encapsulation of BRSKI packets including GRASP
used for BRSKI. used for BRSKI.
A.10.3. ACP APIs and operational models (YANG) A.10.3. ACP APIs and operational models (YANG)
Future work should define YANG ([RFC7950]) data model and/or node Future work should define YANG ([RFC7950]) data model and/or node
internal APIs to monitor and manage the ACP. internal APIs to monitor and manage the ACP.
Support for the ACP Adjacency Table (Section 6.2) and ACP GRASP need Support for the ACP Adjacency Table (Section 6.3) and ACP GRASP need
to be included into such model/API. to be included into such model/API.
A.10.4. RPL enhancements A.10.4. RPL enhancements
..... USA ...... ..... Europe ...... ..... USA ...... ..... Europe ......
NOC1 NOC2 NOC1 NOC2
| | | |
| metric 100 | | metric 100 |
ACP1 --------------------------- ACP2 . ACP1 --------------------------- ACP2 .
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traffic (but only to decrypt the traffic), a downgrade attack could traffic (but only to decrypt the traffic), a downgrade attack could
be discovered after a secure channel connection is established, for be discovered after a secure channel connection is established, for
example by use of the following type of mechanism: example by use of the following type of mechanism:
After the secure channel connection is established, the two ACP peers After the secure channel connection is established, the two ACP peers
negotiate via an appropriate (To Be Defined) GRASP negotiation which negotiate via an appropriate (To Be Defined) GRASP negotiation which
ACP secure channel protocol should have been selected between them ACP secure channel protocol should have been selected between them
(in the absence of a MITM attacker). This negotiation would have to (in the absence of a MITM attacker). This negotiation would have to
signal the DULL GRASP announced ACP secure channel options by each signal the DULL GRASP announced ACP secure channel options by each
peer followed by an announcement of the preferred secure channel peer followed by an announcement of the preferred secure channel
protocol by the ACP peer that is Alice in the secure channel setup, protocol by the ACP peer that is the Decider in the secure channel
e.g.: the ACP peer that is deciding which secure channel protocol to setup, e.g.: the ACP peer that is deciding which secure channel
pick. If that choosen secure channel protocol is different from the protocol to pick. If that choosen secure channel protocol is
one that actually was choosen, then this mismatch is an indication different from the one that actually was choosen, then this mismatch
that there is a MITM attacker or other similar issue (firewall is an indication that there is a MITM attacker or other similar issue
prohibiting the use of specific protocols) that caused a non- (firewall prohibiting the use of specific protocols) that caused a
preferred secure channel protocol to be chosen. This discovery could non-preferred secure channel protocol to be chosen. This discovery
then result in mitigation options such as logging and ensueing could then result in mitigation options such as logging and ensueing
investigations. investigations.
Authors' Addresses Authors' Addresses
Toerless Eckert (editor) Toerless Eckert (editor)
Futurewei Technologies Inc. USA Futurewei Technologies Inc. USA
2330 Central Expy 2330 Central Expy
Santa Clara, 95050 Santa Clara, 95050
United States of America United States of America
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