draft-ietf-6man-segment-routing-header-05.txt   draft-ietf-6man-segment-routing-header-06.txt 
Network Working Group S. Previdi, Ed. Network Working Group S. Previdi, Ed.
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems, Inc. Intended status: Standards Track K. Raza
Expires: August 5, 2017 B. Field Expires: September 14, 2017 D. Dukes
Cisco Systems, Inc.
J. Leddy
B. Field
Comcast Comcast
D. Voyer
D. Bernier
Bell Canada
S. Matsushima
Softbank
I. Leung I. Leung
Rogers Communications Rogers Communications
J. Linkova J. Linkova
Google Google
E. Aries E. Aries
Facebook Facebook
T. Kosugi T. Kosugi
NTT NTT
E. Vyncke E. Vyncke
Cisco Systems, Inc. Cisco Systems, Inc.
D. Lebrun D. Lebrun
Universite Catholique de Louvain Universite Catholique de Louvain
February 1, 2017 D. Steinberg
Steinberg Consulting
R. Raszuk
Bloomberg
March 13, 2017
IPv6 Segment Routing Header (SRH) IPv6 Segment Routing Header (SRH)
draft-ietf-6man-segment-routing-header-05 draft-ietf-6man-segment-routing-header-06
Abstract Abstract
Segment Routing (SR) allows a node to steer a packet through a Segment Routing (SR) allows a node to steer a packet through a
controlled set of instructions, called segments, by prepending an SR controlled set of instructions, called segments, by prepending an SR
header to the packet. A segment can represent any instruction, header to the packet. A segment can represent any instruction,
topological or service-based. SR allows to enforce a flow through topological or service-based. SR allows to enforce a flow through
any path (topological, or application/service based) while any path (topological, or application/service based) while
maintaining per-flow state only at the ingress node to the SR domain. maintaining per-flow state only at the ingress node to the SR domain.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 5, 2017. This Internet-Draft will expire on September 14, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Segment Routing Documents . . . . . . . . . . . . . . . . . . 3 1. Segment Routing Documents . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Data Planes supporting Segment Routing . . . . . . . . . 4 2.1. Data Planes supporting Segment Routing . . . . . . . . . 4
2.2. Segment Routing (SR) Domain . . . . . . . . . . . . . . . 4 2.2. SRv6 Segment . . . . . . . . . . . . . . . . . . . . . . 5
2.2.1. SR Domain in a Service Provider Network . . . . . . . 5 2.3. Segment Routing (SR) Domain . . . . . . . . . . . . . . . 5
2.2.2. SR Domain in a Overlay Network . . . . . . . . . . . 6 2.3.1. SR Domain in a Service Provider Network . . . . . . . 6
3. Segment Routing Extension Header (SRH) . . . . . . . . . . . 7 2.3.2. SR Domain in a Overlay Network . . . . . . . . . . . 7
3.1. SRH TLVs . . . . . . . . . . . . . . . . . . . . . . . . 9 3. Segment Routing Extension Header (SRH) . . . . . . . . . . . 8
3.1.1. Ingress Node TLV . . . . . . . . . . . . . . . . . . 10 3.1. SRH TLVs . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1.2. Egress Node TLV . . . . . . . . . . . . . . . . . . . 11 3.1.1. Ingress Node TLV . . . . . . . . . . . . . . . . . . 11
3.1.3. Opaque Container TLV . . . . . . . . . . . . . . . . 11 3.1.2. Egress Node TLV . . . . . . . . . . . . . . . . . . . 12
3.1.4. Padding TLV . . . . . . . . . . . . . . . . . . . . . 12 3.1.3. Opaque Container TLV . . . . . . . . . . . . . . . . 13
3.1.5. HMAC TLV . . . . . . . . . . . . . . . . . . . . . . 13 3.1.4. Padding TLV . . . . . . . . . . . . . . . . . . . . . 13
3.2. SRH and RFC2460 behavior . . . . . . . . . . . . . . . . 14 3.1.5. HMAC TLV . . . . . . . . . . . . . . . . . . . . . . 14
4. SRH Procedures . . . . . . . . . . . . . . . . . . . . . . . 14 3.1.6. NSH Carrier TLV . . . . . . . . . . . . . . . . . . . 15
4.1. Source SR Node . . . . . . . . . . . . . . . . . . . . . 14 3.2. SRH and RFC2460 behavior . . . . . . . . . . . . . . . . 16
4.2. Transit Node . . . . . . . . . . . . . . . . . . . . . . 15 4. SRH Functions . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3. SR Segment Endpoint Node . . . . . . . . . . . . . . . . 16 4.1. Endpoint Function (End) . . . . . . . . . . . . . . . . . 16
5. Security Considerations . . . . . . . . . . . . . . . . . . . 16 4.2. End.X: Endpoint with Layer-3 cross-connect . . . . . . . 17
5.1. Threat model . . . . . . . . . . . . . . . . . . . . . . 17 5. SR Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.1. Source routing threats . . . . . . . . . . . . . . . 17 5.1. Source SR Node . . . . . . . . . . . . . . . . . . . . . 18
5.1.2. Applicability of RFC 5095 to SRH . . . . . . . . . . 17 5.2. Transit Node . . . . . . . . . . . . . . . . . . . . . . 19
5.1.3. Service stealing threat . . . . . . . . . . . . . . . 18 5.3. SR Segment Endpoint Node . . . . . . . . . . . . . . . . 20
5.1.4. Topology disclosure . . . . . . . . . . . . . . . . . 18 6. Security Considerations . . . . . . . . . . . . . . . . . . . 20
5.1.5. ICMP Generation . . . . . . . . . . . . . . . . . . . 18 6.1. Threat model . . . . . . . . . . . . . . . . . . . . . . 21
5.2. Security fields in SRH . . . . . . . . . . . . . . . . . 19 6.1.1. Source routing threats . . . . . . . . . . . . . . . 21
5.2.1. Selecting a hash algorithm . . . . . . . . . . . . . 20 6.1.2. Applicability of RFC 5095 to SRH . . . . . . . . . . 21
5.2.2. Performance impact of HMAC . . . . . . . . . . . . . 21 6.1.3. Service stealing threat . . . . . . . . . . . . . . . 22
5.2.3. Pre-shared key management . . . . . . . . . . . . . . 21 6.1.4. Topology disclosure . . . . . . . . . . . . . . . . . 22
5.3. Deployment Models . . . . . . . . . . . . . . . . . . . . 22 6.1.5. ICMP Generation . . . . . . . . . . . . . . . . . . . 22
5.3.1. Nodes within the SR domain . . . . . . . . . . . . . 22 6.2. Security fields in SRH . . . . . . . . . . . . . . . . . 23
5.3.2. Nodes outside of the SR domain . . . . . . . . . . . 22 6.2.1. Selecting a hash algorithm . . . . . . . . . . . . . 24
5.3.3. SR path exposure . . . . . . . . . . . . . . . . . . 23 6.2.2. Performance impact of HMAC . . . . . . . . . . . . . 25
5.3.4. Impact of BCP-38 . . . . . . . . . . . . . . . . . . 23 6.2.3. Pre-shared key management . . . . . . . . . . . . . . 25
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 6.3. Deployment Models . . . . . . . . . . . . . . . . . . . . 26
7. Manageability Considerations . . . . . . . . . . . . . . . . 24 6.3.1. Nodes within the SR domain . . . . . . . . . . . . . 26
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24 6.3.2. Nodes outside of the SR domain . . . . . . . . . . . 26
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24 6.3.3. SR path exposure . . . . . . . . . . . . . . . . . . 27
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.3.4. Impact of BCP-38 . . . . . . . . . . . . . . . . . . 27
10.1. Normative References . . . . . . . . . . . . . . . . . . 25 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
10.2. Informative References . . . . . . . . . . . . . . . . . 25 7.1. Segment Routing Header TLVs Register . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27 8. Manageability Considerations . . . . . . . . . . . . . . . . 28
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 28
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
11.1. Normative References . . . . . . . . . . . . . . . . . . 29
11.2. Informative References . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Segment Routing Documents 1. Segment Routing Documents
Segment Routing terminology is defined in Segment Routing terminology is defined in
[I-D.ietf-spring-segment-routing]. [I-D.ietf-spring-segment-routing].
The network programming paradigm
[I-D.filsfils-spring-srv6-network-programming] defines the basic
functions associated to an SRv6 SID.
Segment Routing use cases are described in [RFC7855] and Segment Routing use cases are described in [RFC7855] and
[I-D.ietf-spring-ipv6-use-cases]. [I-D.ietf-spring-ipv6-use-cases].
Segment Routing protocol extensions are defined in Segment Routing protocol extensions are defined in
[I-D.ietf-isis-segment-routing-extensions], and [I-D.ietf-isis-segment-routing-extensions], and
[I-D.ietf-ospf-ospfv3-segment-routing-extensions]. [I-D.ietf-ospf-ospfv3-segment-routing-extensions].
2. Introduction 2. Introduction
Segment Routing (SR), defined in [I-D.ietf-spring-segment-routing], Segment Routing (SR), defined in [I-D.ietf-spring-segment-routing],
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([I-D.ietf-spring-segment-routing-mpls]) and IPv6. This document ([I-D.ietf-spring-segment-routing-mpls]) and IPv6. This document
defines its instantiation over the IPv6 data-plane based on the use- defines its instantiation over the IPv6 data-plane based on the use-
cases defined in [I-D.ietf-spring-ipv6-use-cases]. cases defined in [I-D.ietf-spring-ipv6-use-cases].
This document defines a new type of Routing Header (originally This document defines a new type of Routing Header (originally
defined in [RFC2460]) called the Segment Routing Header (SRH) in defined in [RFC2460]) called the Segment Routing Header (SRH) in
order to convey the Segment List in the packet header as defined in order to convey the Segment List in the packet header as defined in
[I-D.ietf-spring-segment-routing]. Mechanisms through which segment [I-D.ietf-spring-segment-routing]. Mechanisms through which segment
are known and advertised are outside the scope of this document. are known and advertised are outside the scope of this document.
A segment is materialized by an IPv6 address. A segment identifies a 2.2. SRv6 Segment
topological instruction or a service instruction. A segment can be
either:
o global: a global segment represents an instruction supported by An SRv6 Segment is a 128-bit value. "SRv6 SID" or simply "SID" are
all nodes in the SR domain and it is instantiated through an IPv6 often used as a shorter reference for "SRv6 Segment".
address globally known in the SR domain.
o local: a local segment represents an instruction supported only by An SRv6-capable node N maintains a "My Local SID Table". This table
the node who originates it and it is instantiated through an IPv6 contains all the local SRv6 segments explicitly instantiated at node
address that is known only by the local node. N. N is the parent node for these SID's.
2.2. Segment Routing (SR) Domain A local SID of N could be an IPv6 address of a local interface of N
but it does not have to. Most often, a local SID is not an address
of a local interface of N. The My Local SID Table is thus not
populated by default with all the addresses of a node.
An illustration is provided in
[I-D.filsfils-spring-srv6-network-programming].
Every SRv6 local SID instantiated has a specific instruction bounded
to it.
This information is stored in the "My Local SID Table". The "My
Local SID Table" has three main purposes:
o Define which local SID's are explicitly instantiated.
o Specify which instruction is bound to each of the instantiated
SID's.
o Store the parameters associated to such instruction (i.e. OIF,
NextHop,...).
A node may receive a packet with an SRv6 SID in the DA without an
SRH. In such case the packet should still be processed by the
Segment Routing engine.
2.3. Segment Routing (SR) Domain
We define the concept of the Segment Routing Domain (SR Domain) as We define the concept of the Segment Routing Domain (SR Domain) as
the set of nodes participating into the source based routing model. the set of nodes participating into the source based routing model.
These nodes may be connected to the same physical infrastructure These nodes may be connected to the same physical infrastructure
(e.g.: a Service Provider's network) as well as nodes remotely (e.g.: a Service Provider's network) as well as nodes remotely
connected to each other (e.g.: an enterprise VPN or an overlay). connected to each other (e.g.: an enterprise VPN or an overlay).
A non-exhaustive list of examples of SR Domains is: A non-exhaustive list of examples of SR Domains is:
o The network of an operator, service provider, content provider, o The network of an operator, service provider, content provider,
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It is assumed in this document that the SRH is added to the packet by It is assumed in this document that the SRH is added to the packet by
its source, consistently with the source routing model defined in its source, consistently with the source routing model defined in
[RFC2460]. For example: [RFC2460]. For example:
o At the node originating the packet (host, server). o At the node originating the packet (host, server).
o At the ingress node of an SR domain where the ingress node o At the ingress node of an SR domain where the ingress node
receives an IPv6 packet and encapsulates it into an outer IPv6 receives an IPv6 packet and encapsulates it into an outer IPv6
header followed by a Segment Routing header. header followed by a Segment Routing header.
2.2.1. SR Domain in a Service Provider Network 2.3.1. SR Domain in a Service Provider Network
The following figure illustrates an SR domain consisting of an The following figure illustrates an SR domain consisting of an
operator's network infrastructure. operator's network infrastructure.
(-------------------------- Operator 1 -----------------------) (-------------------------- Operator 1 -----------------------)
( ) ( )
( (-----AS 1-----) (-------AS 2-------) (----AS 3-------) ) ( (-----AS 1-----) (-------AS 2-------) (----AS 3-------) )
( ( ) ( ) ( ) ) ( ( ) ( ) ( ) )
A1--(--(--11---13--14-)--(-21---22---23--24-)--(-31---32---34--)--)--Z1 A1--(--(--11---13--14-)--(-21---22---23--24-)--(-31---32---34--)--)--Z1
( ( /|\ /|\ /| ) ( |\ /|\ /|\ /| ) ( |\ /|\ /| \ ) ) ( ( /|\ /|\ /| ) ( |\ /|\ /|\ /| ) ( |\ /|\ /| \ ) )
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engineering, data-center traffic engineering as described in engineering, data-center traffic engineering as described in
[RFC7855], [I-D.ietf-spring-ipv6-use-cases] and [RFC7855], [I-D.ietf-spring-ipv6-use-cases] and
[I-D.ietf-spring-resiliency-use-cases]. [I-D.ietf-spring-resiliency-use-cases].
Typically, an IPv6 packet received at ingress (i.e.: from outside the Typically, an IPv6 packet received at ingress (i.e.: from outside the
SR domain), is classified according to network operator policies and SR domain), is classified according to network operator policies and
such classification results into an outer header with an SRH applied such classification results into an outer header with an SRH applied
to the incoming packet. The SRH contains the list of segment to the incoming packet. The SRH contains the list of segment
representing the path the packet must take inside the SR domain. representing the path the packet must take inside the SR domain.
Thus, the SA of the packet is the ingress node, the DA (due to SRH Thus, the SA of the packet is the ingress node, the DA (due to SRH
procedures described in Section 4) is set as the first segment of the procedures described in Section 5) is set as the first segment of the
path and the last segment of the path is the egress node of the SR path and the last segment of the path is the egress node of the SR
domain. domain.
The path may include intra-AS as well as inter-AS segments. It has The path may include intra-AS as well as inter-AS segments. It has
to be noted that all nodes within the SR domain are under control of to be noted that all nodes within the SR domain are under control of
the same administration. When the packet reaches the egress point of the same administration. When the packet reaches the egress point of
the SR domain, the outer header and its SRH are removed so that the the SR domain, the outer header and its SRH are removed so that the
destination of the packet is unaware of the SR domain the packet has destination of the packet is unaware of the SR domain the packet has
traversed. traversed.
The outer header with the SRH is no different from any other The outer header with the SRH is no different from any other
tunneling encapsulation mechanism and allows a network operator to tunneling encapsulation mechanism and allows a network operator to
implement traffic engineering mechanisms so to efficiently steer implement traffic engineering mechanisms so to efficiently steer
traffic across his infrastructure. traffic across his infrastructure.
2.2.2. SR Domain in a Overlay Network 2.3.2. SR Domain in a Overlay Network
The following figure illustrates an SR domain consisting of an The following figure illustrates an SR domain consisting of an
overlay network over multiple operator's networks. overlay network over multiple operator's networks.
(--Operator 1---) (-----Operator 2-----) (--Operator 3---) (--Operator 1---) (-----Operator 2-----) (--Operator 3---)
( ) ( ) ( ) ( ) ( ) ( )
A1--(--11---13--14--)--(--21---22---23--24--)--(-31---32---34--)--C1 A1--(--11---13--14--)--(--21---22---23--24--)--(-31---32---34--)--C1
( /|\ /|\ /| ) ( |\ /|\ /|\ /| ) ( |\ /|\ /| \ ) ( /|\ /|\ /| ) ( |\ /|\ /|\ /| ) ( |\ /|\ /| \ )
A2--(/ | \/ | \/ | ) ( | \/ | \/ | \/ | ) ( | \/ | \/ | \)--C2 A2--(/ | \/ | \/ | ) ( | \/ | \/ | \/ | ) ( | \/ | \/ | \)--C2
( | /\ | /\ | ) ( | /\ | /\ | /\ | ) ( | /\ | /\ | ) ( | /\ | /\ | ) ( | /\ | /\ | /\ | ) ( | /\ | /\ | )
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defined: the Segment Routing Header (SRH) which has a new Routing defined: the Segment Routing Header (SRH) which has a new Routing
Type, (suggested value 4) to be assigned by IANA. Type, (suggested value 4) to be assigned by IANA.
The Segment Routing Header (SRH) is defined as follows: The Segment Routing Header (SRH) is defined as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segments Left | | Next Header | Hdr Ext Len | Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| First Segment | Flags | RESERVED | | Last Entry | Flags | Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Segment List[0] (128 bits IPv6 address) | | Segment List[0] (128 bits IPv6 address) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| | | |
... ...
| | | |
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o Hdr Ext Len: 8-bit unsigned integer, is the length of the SRH o Hdr Ext Len: 8-bit unsigned integer, is the length of the SRH
header in 8-octet units, not including the first 8 octets. header in 8-octet units, not including the first 8 octets.
o Routing Type: TBD, to be assigned by IANA (suggested value: 4). o Routing Type: TBD, to be assigned by IANA (suggested value: 4).
o Segments Left. Defined in [RFC2460], it contains the index, in o Segments Left. Defined in [RFC2460], it contains the index, in
the Segment List, of the next segment to inspect. Segments Left the Segment List, of the next segment to inspect. Segments Left
is decremented at each segment. is decremented at each segment.
o First Segment: contains the index, in the Segment List, of the o Last Entry: contains the index, in the Segment List, of the last
first segment of the path which is in fact the last element of the element of the Segment List.
Segment List.
o Flags: 8 bits of flags. Following flags are defined: o Flags: 8 bits of flags. Following flags are defined:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|U|P|O|A|H| U | |U|P|O|A|H| U |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
U: Unused and for future use. SHOULD be unset on transmission U: Unused and for future use. SHOULD be unset on transmission
and MUST be ignored on receipt. and MUST be ignored on receipt.
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A-flag: Alert flag. If present, it means important Type Length A-flag: Alert flag. If present, it means important Type Length
Value (TLV) objects are present. See Section 3.1 for details Value (TLV) objects are present. See Section 3.1 for details
on TLVs objects. on TLVs objects.
H-flag: HMAC flag. If set, the HMAC TLV is present and is H-flag: HMAC flag. If set, the HMAC TLV is present and is
encoded as the last TLV of the SRH. In other words, the last encoded as the last TLV of the SRH. In other words, the last
36 octets of the SRH represent the HMAC information. See 36 octets of the SRH represent the HMAC information. See
Section 3.1.5 for details on the HMAC TLV. Section 3.1.5 for details on the HMAC TLV.
o RESERVED: SHOULD be unset on transmission and MUST be ignored on o Tag: tag a packet as part of a class or group of packets, e.g.,
receipt. packets sharing the same set of properties.
o Segment List[n]: 128 bit IPv6 addresses representing the nth o Segment List[n]: 128 bit IPv6 addresses representing the nth
segment in the Segment List. The Segment List is encoded starting segment in the Segment List. The Segment List is encoded starting
from the last segment of the path. I.e., the first element of the from the last segment of the path. I.e., the first element of the
segment list (Segment List [0]) contains the last segment of the segment list (Segment List [0]) contains the last segment of the
path while the last segment of the Segment List (Segment List[n]) path, the second element contains the penultimate segment of the
contains the first segment of the path. The index contained in path and so on.
"Segments Left" identifies the current active segment.
o Type Length Value (TLV) are described in Section 3.1. o Type Length Value (TLV) are described in Section 3.1.
3.1. SRH TLVs 3.1. SRH TLVs
This section defines TLVs of the Segment Routing Header. This section defines TLVs of the Segment Routing Header.
Type Length Value (TLV) contain optional information that may be used Type Length Value (TLV) contain optional information that may be used
by the node identified in the DA of the packet. It has to be noted by the node identified in the DA of the packet. It has to be noted
that the information carried in the TLVs is not intended to be used that the information carried in the TLVs is not intended to be used
skipping to change at page 10, line 12 skipping to change at page 11, line 12
Each TLV has its own length, format and semantic. The code-point Each TLV has its own length, format and semantic. The code-point
allocated (by IANA) to each TLV defines both the format and the allocated (by IANA) to each TLV defines both the format and the
semantic of the information carried in the TLV. Multiple TLVs may be semantic of the information carried in the TLV. Multiple TLVs may be
encoded in the same SRH. encoded in the same SRH.
The "Length" field of the TLV is primarily used to skip the TLV while The "Length" field of the TLV is primarily used to skip the TLV while
inspecting the SRH in case the node doesn't support or recognize the inspecting the SRH in case the node doesn't support or recognize the
TLV codepoint. The "Length" defines the TLV length in octets and not TLV codepoint. The "Length" defines the TLV length in octets and not
including the "Type" and "Length" fields. including the "Type" and "Length" fields.
The primary scope of TLVs is to give the receiver of the packet The following TLVs are defined in this document:
information related to the source routed path (e.g.: where the packet
entered in the SR domain and where it is expected to exit). Ingress Node TLV
Egress Node TLV
Opaque TLV
Padding TLV
HMAC TLV
NSH Carrier TLV
Additional TLVs may be defined in the future. Additional TLVs may be defined in the future.
3.1.1. Ingress Node TLV 3.1.1. Ingress Node TLV
The Ingress Node TLV is optional and identifies the node this packet The Ingress Node TLV is optional and identifies the node this packet
traversed when entered the SR domain. The Ingress Node TLV has traversed when entered the SR domain. The Ingress Node TLV has
following format: following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | RESERVED | Flags | | Type | Length | RESERVED | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Ingress Node (16 octets) | | Ingress Node (16 octets) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
o Type: to be assigned by IANA (suggested value 1). o Type: to be assigned by IANA (suggested value 1).
o Length: 18. o Length: 18.
o RESERVED: 8 bits. SHOULD be unset on transmission and MUST be o RESERVED: 8 bits. SHOULD be unset on transmission and MUST be
ignored on receipt. ignored on receipt.
o Flags: 8 bits. No flags are defined in this document. o Flags: 8 bits. No flags are defined in this document. SHOULD be
set to 0 on transmission and MUST be ignored on receipt.
o Ingress Node: 128 bits. Defines the node where the packet is o Ingress Node: 128 bits. Defines the node where the packet is
expected to enter the SR domain. In the encapsulation case expected to enter the SR domain. In the encapsulation case
described in Section 2.2.1, this information corresponds to the SA described in Section 2.3.1, this information corresponds to the SA
of the encapsulating header. of the encapsulating header.
3.1.2. Egress Node TLV 3.1.2. Egress Node TLV
The Egress Node TLV is optional and identifies the node this packet The Egress Node TLV is optional and identifies the node this packet
is expected to traverse when exiting the SR domain. The Egress Node is expected to traverse when exiting the SR domain. The Egress Node
TLV has following format: TLV has following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 11, line 31 skipping to change at page 12, line 42
where: where:
o Type: to be assigned by IANA (suggested value 2). o Type: to be assigned by IANA (suggested value 2).
o Length: 18. o Length: 18.
o RESERVED: 8 bits. SHOULD be unset on transmission and MUST be o RESERVED: 8 bits. SHOULD be unset on transmission and MUST be
ignored on receipt. ignored on receipt.
o Flags: 8 bits. No flags are defined in this document. o Flags: 8 bits. No flags are defined in this document. SHOULD be
set to 0 on transmission and MUST be ignored on receipt.
o Egress Node: 128 bits. Defines the node where the packet is o Egress Node: 128 bits. Defines the node where the packet is
expected to exit the SR domain. In the encapsulation case expected to exit the SR domain. In the encapsulation case
described in Section 2.2.1, this information corresponds to the described in Section 2.3.1, this information corresponds to the
last segment of the SRH in the encapsulating header. last segment of the SRH in the encapsulating header.
3.1.3. Opaque Container TLV 3.1.3. Opaque Container TLV
The Opaque Container TLV is optional and has the following format: The Opaque Container TLV is optional and has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | RESERVED | Flags | | Type | Length | RESERVED | Flags |
skipping to change at page 12, line 25 skipping to change at page 13, line 29
where: where:
o Type: to be assigned by IANA (suggested value 3). o Type: to be assigned by IANA (suggested value 3).
o Length: 18. o Length: 18.
o RESERVED: 8 bits. SHOULD be unset on transmission and MUST be o RESERVED: 8 bits. SHOULD be unset on transmission and MUST be
ignored on receipt. ignored on receipt.
o Flags: 8 bits. No flags are defined in this document. o Flags: 8 bits. No flags are defined in this document. SHOULD be
set to 0 on transmission and MUST be ignored on receipt.
o Opaque Container: 128 bits of opaque data not relevant for the o Opaque Container: 128 bits of opaque data not relevant for the
routing layer. Typically, this information is consumed by a non- routing layer. Typically, this information is consumed by a non-
routing component of the node receiving the packet (i.e.: the node routing component of the node receiving the packet (i.e.: the node
in the DA). in the DA).
3.1.4. Padding TLV 3.1.4. Padding TLV
The Padding TLV is optional and with the purpose of aligning the SRH The Padding TLV is optional and with the purpose of aligning the SRH
on a 8 octet boundary. The Padding TLV has the following format: on a 8 octet boundary. The Padding TLV has the following format:
skipping to change at page 14, line 9 skipping to change at page 15, line 12
o Length: 38. o Length: 38.
o RESERVED: 2 octets. SHOULD be unset on transmission and MUST be o RESERVED: 2 octets. SHOULD be unset on transmission and MUST be
ignored on receipt. ignored on receipt.
o HMAC Key ID: 4 octets. o HMAC Key ID: 4 octets.
o HMAC: 32 octets. o HMAC: 32 octets.
o HMAC and HMAC Key ID usage is described in Section 5 o HMAC and HMAC Key ID usage is described in Section 6
The Following applies to the HMAC TLV: The Following applies to the HMAC TLV:
o When present, the HMAC TLV MUST be encoded as the last TLV of the o When present, the HMAC TLV MUST be encoded as the last TLV of the
SRH. SRH.
o If the HMAC TLV is present, the SRH H-Flag (Figure 4) MUST be set. o If the HMAC TLV is present, the SRH H-Flag (Figure 4) MUST be set.
o When the H-flag is set in the SRH, the router inspecting the SRH o When the H-flag is set in the SRH, the router inspecting the SRH
MUST find the HMAC TLV in the last 38 octets of the SRH. MUST find the HMAC TLV in the last 38 octets of the SRH.
3.1.6. NSH Carrier TLV
The NSH Carrier TLV is a container used in order to carry TLVs that
have been defined in [I-D.ietf-sfc-nsh]. The NSH Carrier TLV has the
following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// NSH Carried Object //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
o Type: to be assigned by IANA (suggested value 6).
o Length: the total length of the TLV.
o Flags: 8 bits. No flags are defined in this document. SHOULD be
set to 0 on transmission and MUST be ignored on receipt.
o NSH Carried Object: the content of the TLV which consists of the
NSH data as defined in [I-D.ietf-sfc-nsh].
3.2. SRH and RFC2460 behavior 3.2. SRH and RFC2460 behavior
The SRH being a new type of the Routing Header, it also has the same The SRH being a new type of the Routing Header, it also has the same
properties: properties:
SHOULD only appear once in the packet. SHOULD only appear once in the packet.
Only the router whose address is in the DA field of the packet Only the router whose address is in the DA field of the packet
header MUST inspect the SRH. header MUST inspect the SRH.
Therefore, Segment Routing in IPv6 networks implies that the segment Therefore, Segment Routing in IPv6 networks implies that the segment
identifier (i.e.: the IPv6 address of the segment) is moved into the identifier (i.e.: the IPv6 address of the segment) is moved into the
DA of the packet. DA of the packet.
The DA of the packet changes at each segment termination/completion The DA of the packet changes at each segment termination/completion
and therefore the final DA of the packet MUST be encoded as the last and therefore the final DA of the packet MUST be encoded as the last
segment of the path. segment of the path.
4. SRH Procedures 4. SRH Functions
In this section we describe the different procedures on the SRH. Segment Routing architecture, as defined in
[I-D.ietf-spring-segment-routing] defines a segment as an instruction
or, more generally, a set of instructions (function).
4.1. Source SR Node [I-D.filsfils-spring-srv6-network-programming] defines the basic
functions associated with SRv6 SID's.
In this section we review two of these functions that may be
associated to a segment:
o End: the endpoint (End) function is the base of the source routing
paradigm. It consists of updating the DA with the next segment
and forward the packet accordingly.
o End.X: The endpoint layer-3 cross-connect function.
More functions are defined in
[I-D.filsfils-spring-srv6-network-programming].
4.1. Endpoint Function (End)
The Endpoint function (End) is the most basic function.
When the endpoint node receives a packet destined to DA "S" and S is
an entry in the MyLocalSID table and the function associated with S
in that entry is "End" then the endpoint does:
1. IF SegmentsLeft > 0 THEN
2. decrement SL
3. update the IPv6 DA with SRH[SL]
4. FIB lookup on updated DA
5. forward accordingly to the matched entry
6. ELSE
7. drop the packet
It has to be noted that:
o The End function performs the FIB lookup in the forwarding table
of the ingress interface.
o If the FIB lookup matches a multicast state, then the related
Reverse Path Forwarding (RPF) check must be considered successful.
o An SRv6-capable node MUST include the FlowLabel of the IPv6 header
in its hash computation for ECMP load-balancing.
o By default, a local SID bound to the End function does not allow
the decapsulation of an outer header. As a consequence, an End
SID cannot be the last SID of an SRH and cannot be the DA of a
packet without SRH.
o If the decapsulation is desired, then another function must be
bound to the SID (e.g., End.DX6 defined in
[I-D.filsfils-spring-srv6-network-programming]). This prevents
any unintentional decapsulation by the segment endpoint node. The
details of the advertisement of a SID in the control plane are
outside the scope of this document (e.g.,
[I-D.previdi-idr-segment-routing-te-policy],
[I-D.dawra-bgp-srv6-vpn] and [I-D.bashandy-isis-srv6-extensions].
4.2. End.X: Endpoint with Layer-3 cross-connect
When the endpoint node receives a packet destined to DA "S" and S is
an entry in the MyLocalSID table and the function associated with S
in that entry is "End.X" then the endpoint does:
1. IF SegmentsLeft > 0 THEN
2. decrement SL
3. update the IPv6 DA with SRH[SL]
4. forward to layer-3 adjacency bound to the SID "S"
5. ELSE
6. drop the packet
It has to be noted that:
o If an array of layer-3 adjacencies is bound to the End.X SID, then
one entry of the array is selected based on a hash of the packet's
header (at least SA, DA, Flow Label).
o An End.X function does not allow decaps. An End.X SID cannot be
the last SID of an SRH and cannot be the DA of a packet without
SRH.
o The End.X function is required to express any traffic-engineering
policy.
o The End.X function is the SRv6 instantiation of a Adjacency SID as
defined in [I-D.ietf-spring-segment-routing].
o Note that with SR-MPLS ([I-D.ietf-spring-segment-routing-mpls]),
an AdjSID is typically preceded by a PrefixSID. This is unlikely
in SRv6 as most likely an End.X SID is globally routed address of
N.
o If a node N has 30 outgoing interfaces to 30 neighbors, usually
the operator would explicitly instantiate 30 End.X SID's at N: one
per layer-3 adjacency to a neighbor. Potentially, more End.X
could be explicitly defined (groups of layer-3 adjacencies to the
same neighbor or to different neighbors).
o If node N has a bundle outgoing interface I to a neighbor Q made
of 10 member links, N may allocate up to 11 End.X local SID's for
that bundle: one for the bundle itself and then up to one for each
member link. This is the equivalent of the L2-Link Adj SID in SR-
MPLS ([I-D.ietf-isis-l2bundles]).
5. SR Nodes
There are different types of nodes that may be involved in segment
routing networks: source nodes that originate packets with an SRH,
transit nodes that forward packets having an SRH and segment endpoint
nodes that MUST process the SRH.
5.1. Source SR Node
A Source SR Node can be any node originating an IPv6 packet with its A Source SR Node can be any node originating an IPv6 packet with its
IPv6 and Segment Routing Headers. This include either: IPv6 and Segment Routing Headers. This include either:
A host originating an IPv6 packet. A host originating an IPv6 packet.
An SR domain ingress router encapsulating a received IPv6 packet An SR domain ingress router encapsulating a received IPv6 packet
into an outer IPv6 header followed by an SRH. into an outer IPv6 header followed by an SRH.
The mechanism through which a Segment List is derived is outside of The mechanism through which a Segment List is derived is outside of
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Any other mechanism. Any other mechanism.
The following are the steps of the creation of the SRH: The following are the steps of the creation of the SRH:
Next Header and Hdr Ext Len fields are set according to [RFC2460]. Next Header and Hdr Ext Len fields are set according to [RFC2460].
Routing Type field is set as TBD (to be allocated by IANA, Routing Type field is set as TBD (to be allocated by IANA,
suggested value 4). suggested value 4).
The Segment List is built with the FIRST segment of the path The DA of the packet is set with the value of the first segment.
encoded in the LAST element of the Segment List. Subsequent ).
segments are encoded on top of the first segment. Finally, the
LAST segment of the path is encoded in the FIRST element of the
Segment List. In other words, the Segment List is encoded in the
reverse order of the path.
The final DA of the packet is encoded as the last segment of the The first element of the segment list is the last segment (the
path (encoded in the first element of the Segment List). final DA of the packet). The second element is the penultimate
segment and so on.
The DA of the packet is set with the value of the first segment In other words, the Segment List is encoded in the reverse order
(found in the last element of the segment list). of the path.
The Segments Left field is set to n-1 where n is the number of The Segments Left field is set to n-1 where n is the number of
elements in the Segment List. elements in the Segment List.
The First Segment field is set to n-1 where n is the number of The Last_Entry field is set to n-1 where n is the number of
elements in the Segment List. elements in the Segment List.
The packet is sent out towards the first segment (i.e.: The packet is sent out towards the packet's DA (the first
represented in the packet DA). segment).
HMAC TLV may be set according to Section 5. HMAC TLV may be set according to Section 6.
4.2. Transit Node If the segment list contains a single segment and there is no need
for information in flag or TLV, then the SRH MAY be omitted.
5.2. Transit Node
According to [RFC2460], the only node who is allowed to inspect the According to [RFC2460], the only node who is allowed to inspect the
Routing Extension Header (and therefore the SRH), is the node Routing Extension Header (and therefore the SRH), is the node
corresponding to the DA of the packet. Any other transit node MUST corresponding to the DA of the packet. Any other transit node MUST
NOT inspect the underneath routing header and MUST forward the packet NOT inspect the underneath routing header and MUST forward the packet
towards the DA and according to the IPv6 routing table. towards the DA and according to the IPv6 routing table.
In the example case described in Section 2.2.2, when SR capable nodes In the example case described in Section 2.3.2, when SR capable nodes
are connected through an overlay spanning multiple third-party are connected through an overlay spanning multiple third-party
infrastructure, it is safe to send SRH packets (i.e.: packet having a infrastructure, it is safe to send SRH packets (i.e.: packet having a
Segment Routing Header) between each other overlay/SR-capable nodes Segment Routing Header) between each other overlay/SR-capable nodes
as long as the segment list does not include any of the transit as long as the segment list does not include any of the transit
provider nodes. In addition, as a generic security measure, any provider nodes. In addition, as a generic security measure, any
service provider will block any packet destined to one of its service provider will block any packet destined to one of its
internal routers, especially if these packets have an extended header internal routers, especially if these packets have an extended header
in it. in it.
4.3. SR Segment Endpoint Node 5.3. SR Segment Endpoint Node
The SR segment endpoint node is the node whose address is in the DA. The SR segment endpoint node is the node whose MyLocalSID table
The segment endpoint node inspects the SRH and does: contains an entry for the DA of the packet.
1. IF DA = myself (segment endpoint) The segment endpoint node executes the function bound to the SID as
2. IF Segments Left > 0 THEN per the matched MyLocalSID entry (Section 4).
decrement Segments Left
update DA with Segment List[Segments Left]
3. ELSE continue IPv6 processing of the packet
End of processing.
4. Forward the packet out
5. Security Considerations 6. Security Considerations
This section analyzes the security threat model, the security issues This section analyzes the security threat model, the security issues
and proposed solutions related to the new Segment Routing Header. and proposed solutions related to the new Segment Routing Header.
The Segment Routing Header (SRH) is simply another type of the The Segment Routing Header (SRH) is simply another type of the
routing header as described in RFC 2460 [RFC2460] and is: routing header as described in RFC 2460 [RFC2460] and is:
o Added by an SR edge router when entering the segment routing o Added by an SR edge router when entering the segment routing
domain or by the originating host itself. The source host can domain or by the originating host itself. The source host can
even be outside the SR domain; even be outside the SR domain;
skipping to change at page 17, line 16 skipping to change at page 21, line 12
capable router upon receipt of an IPv6 packet with SRH destined to an capable router upon receipt of an IPv6 packet with SRH destined to an
address of its, is to: address of its, is to:
o ignore the SRH completely if the Segment Left field is 0 and o ignore the SRH completely if the Segment Left field is 0 and
proceed to process the next header in the IPv6 packet; proceed to process the next header in the IPv6 packet;
o discard the IPv6 packet if Segment Left field is greater than 0, o discard the IPv6 packet if Segment Left field is greater than 0,
it MAY send a Parameter Problem ICMP message back to the Source it MAY send a Parameter Problem ICMP message back to the Source
Address. Address.
5.1. Threat model 6.1. Threat model
5.1.1. Source routing threats 6.1.1. Source routing threats
Using an SRH is similar to source routing, therefore it has some Using an SRH is similar to source routing, therefore it has some
well-known security issues as described in RFC4942 [RFC4942] section well-known security issues as described in RFC4942 [RFC4942] section
2.1.1 and RFC5095 [RFC5095]: 2.1.1 and RFC5095 [RFC5095]:
o amplification attacks: where a packet could be forged in such a o amplification attacks: where a packet could be forged in such a
way to cause looping among a set of SR-enabled routers causing way to cause looping among a set of SR-enabled routers causing
unnecessary traffic, hence a Denial of Service (DoS) against unnecessary traffic, hence a Denial of Service (DoS) against
bandwidth; bandwidth;
o reflection attack: where a hacker could force an intermediate node o reflection attack: where a hacker could force an intermediate node
to appear as the immediate attacker, hence hiding the real to appear as the immediate attacker, hence hiding the real
attacker from naive forensic; attacker from naive forensic;
o bypass attack: where an intermediate node could be used as a o bypass attack: where an intermediate node could be used as a
stepping stone (for example in a De-Militarized Zone) to attack stepping stone (for example in a De-Militarized Zone) to attack
another host (for example in the datacenter or any back-end another host (for example in the datacenter or any back-end
server). server).
5.1.2. Applicability of RFC 5095 to SRH 6.1.2. Applicability of RFC 5095 to SRH
First of all, the reader must remember this specific part of section First of all, the reader must remember this specific part of section
1 of RFC5095 [RFC5095], "A side effect is that this also eliminates 1 of RFC5095 [RFC5095], "A side effect is that this also eliminates
benign RH0 use-cases; however, such applications may be facilitated benign RH0 use-cases; however, such applications may be facilitated
by future Routing Header specifications.". In short, it is not by future Routing Header specifications.". In short, it is not
forbidden to create new secure type of Routing Header; for example, forbidden to create new secure type of Routing Header; for example,
RFC 6554 (RPL) [RFC6554] also creates a new Routing Header type for a RFC 6554 (RPL) [RFC6554] also creates a new Routing Header type for a
specific application confined in a single network. specific application confined in a single network.
In the segment routing architecture described in In the segment routing architecture described in
skipping to change at page 18, line 32 skipping to change at page 22, line 26
their domain. their domain.
Moreover, all SR nodes ignore SRH created by outsiders based on Moreover, all SR nodes ignore SRH created by outsiders based on
topology information (received on a peering or internal interface) or topology information (received on a peering or internal interface) or
on presence and validity of the HMAC field. Therefore, if on presence and validity of the HMAC field. Therefore, if
intermediate nodes ONLY act on valid and authorized SRH (such as intermediate nodes ONLY act on valid and authorized SRH (such as
within a single administrative domain), then there is no security within a single administrative domain), then there is no security
threat similar to RH-0. Hence, the RFC 5095 [RFC5095] attacks are threat similar to RH-0. Hence, the RFC 5095 [RFC5095] attacks are
not applicable. not applicable.
5.1.3. Service stealing threat 6.1.3. Service stealing threat
Segment routing is used for added value services, there is also a Segment routing is used for added value services, there is also a
need to prevent non-participating nodes to use those services; this need to prevent non-participating nodes to use those services; this
is called 'service stealing prevention'. is called 'service stealing prevention'.
5.1.4. Topology disclosure 6.1.4. Topology disclosure
The SRH may also contains IPv6 addresses of some intermediate SR- The SRH may also contains IPv6 addresses of some intermediate SR-
nodes in the path towards the destination, this obviously reveals nodes in the path towards the destination, this obviously reveals
those addresses to the potentially hostile attackers if those those addresses to the potentially hostile attackers if those
attackers are able to intercept packets containing SRH. On the other attackers are able to intercept packets containing SRH. On the other
hand, if the attacker can do a traceroute whose probes will be hand, if the attacker can do a traceroute whose probes will be
forwarded along the SR path, then there is little learned by forwarded along the SR path, then there is little learned by
intercepting the SRH itself. intercepting the SRH itself.
5.1.5. ICMP Generation 6.1.5. ICMP Generation
Per section 4.4 of RFC2460 [RFC2460], when destination nodes (i.e. Per section 4.4 of RFC2460 [RFC2460], when destination nodes (i.e.
where the destination address is one of theirs) receive a Routing where the destination address is one of theirs) receive a Routing
Header with unsupported Routing Type, the required behavior is: Header with unsupported Routing Type, the required behavior is:
o If Segments Left is zero, the node must ignore the Routing header o If Segments Left is zero, the node must ignore the Routing header
and proceed to process the next header in the packet. and proceed to process the next header in the packet.
o If Segments Left is non-zero, the node must discard the packet and o If Segments Left is non-zero, the node must discard the packet and
send an ICMP Parameter Problem, Code 0, message to the packet's send an ICMP Parameter Problem, Code 0, message to the packet's
skipping to change at page 19, line 26 skipping to change at page 23, line 23
generate an ICMP message, causing a local CPU utilization and if the generate an ICMP message, causing a local CPU utilization and if the
source of the offending packet with SRH was spoofed could lead to a source of the offending packet with SRH was spoofed could lead to a
reflection attack without any amplification. reflection attack without any amplification.
It must be noted that this is a required behavior for any unsupported It must be noted that this is a required behavior for any unsupported
Routing Type and not limited to SRH packets. So, it is not specific Routing Type and not limited to SRH packets. So, it is not specific
to SRH and the usual rate limiting for ICMP generation is required to SRH and the usual rate limiting for ICMP generation is required
anyway for any IPv6 implementation and has been implemented and anyway for any IPv6 implementation and has been implemented and
deployed for many years. deployed for many years.
5.2. Security fields in SRH 6.2. Security fields in SRH
This section summarizes the use of specific fields in the SRH. They This section summarizes the use of specific fields in the SRH. They
are based on a key-hashed message authentication code (HMAC). are based on a key-hashed message authentication code (HMAC).
The security-related fields in the SRH are instantiated by the HMAC The security-related fields in the SRH are instantiated by the HMAC
TLV, containing: TLV, containing:
o HMAC Key-id, 32 bits wide; o HMAC Key-id, 32 bits wide;
o HMAC, 256 bits wide (optional, exists only if HMAC Key-id is not o HMAC, 256 bits wide (optional, exists only if HMAC Key-id is not
0). 0).
The HMAC field is the output of the HMAC computation (per RFC 2104 The HMAC field is the output of the HMAC computation (per RFC 2104
[RFC2104]) using a pre-shared key identified by HMAC Key-id and of [RFC2104]) using a pre-shared key identified by HMAC Key-id and of
the text which consists of the concatenation of: the text which consists of the concatenation of:
o the source IPv6 address; o the source IPv6 address;
o First Segment field; o Last Entry field;
o an octet of bit flags; o an octet of bit flags;
o HMAC Key-id; o HMAC Key-id;
o all addresses in the Segment List. o all addresses in the Segment List.
The purpose of the HMAC TLV is to verify the validity, the integrity The purpose of the HMAC TLV is to verify the validity, the integrity
and the authorization of the SRH itself. If an outsider of the SR and the authorization of the SRH itself. If an outsider of the SR
domain does not have access to a current pre-shared secret, then it domain does not have access to a current pre-shared secret, then it
skipping to change at page 20, line 37 skipping to change at page 24, line 33
pre-shared key. It could also allow for interoperation among pre-shared key. It could also allow for interoperation among
different SR domains if allowed by local policy and assuming a different SR domains if allowed by local policy and assuming a
collision-free HMAC Key Id allocation. collision-free HMAC Key Id allocation.
When a specific SRH is linked to a time-related service (such as When a specific SRH is linked to a time-related service (such as
turbo-QoS for a 1-hour period) where the DA, Segment ID (SID) are turbo-QoS for a 1-hour period) where the DA, Segment ID (SID) are
identical, then it is important to refresh the shared-secret identical, then it is important to refresh the shared-secret
frequently as the HMAC validity period expires only when the HMAC frequently as the HMAC validity period expires only when the HMAC
Key-id and its associated shared-secret expires. Key-id and its associated shared-secret expires.
5.2.1. Selecting a hash algorithm 6.2.1. Selecting a hash algorithm
The HMAC field in the HMAC TLV is 256 bit wide. Therefore, the HMAC The HMAC field in the HMAC TLV is 256 bit wide. Therefore, the HMAC
MUST be based on a hash function whose output is at least 256 bits. MUST be based on a hash function whose output is at least 256 bits.
If the output of the hash function is 256, then this output is simply If the output of the hash function is 256, then this output is simply
inserted in the HMAC field. If the output of the hash function is inserted in the HMAC field. If the output of the hash function is
larger than 256 bits, then the output value is truncated to 256 by larger than 256 bits, then the output value is truncated to 256 by
taking the least-significant 256 bits and inserting them in the HMAC taking the least-significant 256 bits and inserting them in the HMAC
field. field.
SRH implementations can support multiple hash functions but MUST SRH implementations can support multiple hash functions but MUST
implement SHA-2 [FIPS180-4] in its SHA-256 variant. implement SHA-2 [FIPS180-4] in its SHA-256 variant.
NOTE: SHA-1 is currently used by some early implementations used for NOTE: SHA-1 is currently used by some early implementations used for
quick interoperations testing, the 160-bit hash value must then be quick interoperations testing, the 160-bit hash value must then be
right-hand padded with 96 bits set to 0. The authors understand that right-hand padded with 96 bits set to 0. The authors understand that
this is not secure but is ok for limited tests. this is not secure but is ok for limited tests.
5.2.2. Performance impact of HMAC 6.2.2. Performance impact of HMAC
While adding an HMAC to each and every SR packet increases the While adding an HMAC to each and every SR packet increases the
security, it has a performance impact. Nevertheless, it must be security, it has a performance impact. Nevertheless, it must be
noted that: noted that:
o the HMAC field is used only when SRH is added by a device (such as o the HMAC field is used only when SRH is added by a device (such as
a home set-up box) which is outside of the segment routing domain. a home set-up box) which is outside of the segment routing domain.
If the SRH is added by a router in the trusted segment routing If the SRH is added by a router in the trusted segment routing
domain, then, there is no need for an HMAC field, hence no domain, then, there is no need for an HMAC field, hence no
performance impact. performance impact.
skipping to change at page 21, line 36 skipping to change at page 25, line 34
same use case as in IPsec where HMAC value was unique per packet, same use case as in IPsec where HMAC value was unique per packet,
in SRH, the HMAC value is unique per flow. in SRH, the HMAC value is unique per flow.
o Last point, hash functions such as SHA-2 have been optimized for o Last point, hash functions such as SHA-2 have been optimized for
security and performance and there are multiple implementations security and performance and there are multiple implementations
with good performance. with good performance.
With the above points in mind, the performance impact of using HMAC With the above points in mind, the performance impact of using HMAC
is minimized. is minimized.
5.2.3. Pre-shared key management 6.2.3. Pre-shared key management
The field HMAC Key-id allows for: The field HMAC Key-id allows for:
o key roll-over: when there is a need to change the key (the hash o key roll-over: when there is a need to change the key (the hash
pre-shared secret), then multiple pre-shared keys can be used pre-shared secret), then multiple pre-shared keys can be used
simultaneously. The validating routing can have a table of <HMAC simultaneously. The validating routing can have a table of <HMAC
Key-id, pre-shared secret> for the currently active and future Key-id, pre-shared secret> for the currently active and future
keys. keys.
o different algorithms: by extending the previous table to <HMAC o different algorithms: by extending the previous table to <HMAC
Key-id, hash function, pre-shared secret>, the validating router Key-id, hash function, pre-shared secret>, the validating router
can also support simultaneously several hash algorithms (see can also support simultaneously several hash algorithms (see
section Section 5.2.1) section Section 6.2.1)
The pre-shared secret distribution can be done: The pre-shared secret distribution can be done:
o in the configuration of the validating routers, either by static o in the configuration of the validating routers, either by static
configuration or any SDN oriented approach; configuration or any SDN oriented approach;
o dynamically using a trusted key distribution such as [RFC6407] o dynamically using a trusted key distribution such as [RFC6407]
The intent of this document is NOT to define yet-another-key- The intent of this document is NOT to define yet-another-key-
distribution-protocol. distribution-protocol.
5.3. Deployment Models 6.3. Deployment Models
5.3.1. Nodes within the SR domain 6.3.1. Nodes within the SR domain
An SR domain is defined as a set of interconnected routers where all An SR domain is defined as a set of interconnected routers where all
routers at the perimeter are configured to add and act on SRH. Some routers at the perimeter are configured to add and act on SRH. Some
routers inside the SR domain can also act on SRH or simply forward routers inside the SR domain can also act on SRH or simply forward
IPv6 packets. IPv6 packets.
The routers inside an SR domain can be trusted to generate SRH and to The routers inside an SR domain can be trusted to generate SRH and to
process SRH received on interfaces that are part of the SR domain. process SRH received on interfaces that are part of the SR domain.
These nodes MUST drop all SRH packets received on an interface that These nodes MUST drop all SRH packets received on an interface that
is not part of the SR domain and containing an SRH whose HMAC field is not part of the SR domain and containing an SRH whose HMAC field
cannot be validated by local policies. This includes obviously cannot be validated by local policies. This includes obviously
packet with an SRH generated by a non-cooperative SR domain. packet with an SRH generated by a non-cooperative SR domain.
If the validation fails, then these packets MUST be dropped, ICMP If the validation fails, then these packets MUST be dropped, ICMP
error messages (parameter problem) SHOULD be generated (but rate error messages (parameter problem) SHOULD be generated (but rate
limited) and SHOULD be logged. limited) and SHOULD be logged.
5.3.2. Nodes outside of the SR domain 6.3.2. Nodes outside of the SR domain
Nodes outside of the SR domain cannot be trusted for physical Nodes outside of the SR domain cannot be trusted for physical
security; hence, they need to request by some trusted means (outside security; hence, they need to request by some trusted means (outside
of the scope of this document) a complete SRH for each new connection of the scope of this document) a complete SRH for each new connection
(i.e. new destination address). The received SRH MUST include an (i.e. new destination address). The received SRH MUST include an
HMAC TLV which is computed correctly (see Section 5.2). HMAC TLV which is computed correctly (see Section 6.2).
When an outside node sends a packet with an SRH and towards an SR When an outside node sends a packet with an SRH and towards an SR
domain ingress node, the packet MUST contain the HMAC TLV (with a domain ingress node, the packet MUST contain the HMAC TLV (with a
Key-id and HMAC fields) and the the destination address MUST be an Key-id and HMAC fields) and the the destination address MUST be an
address of an SR domain ingress node . address of an SR domain ingress node .
The ingress SR router, i.e., the router with an interface address The ingress SR router, i.e., the router with an interface address
equals to the destination address, MUST verify the HMAC TLV. equals to the destination address, MUST verify the HMAC TLV.
If the validation is successful, then the packet is simply forwarded If the validation is successful, then the packet is simply forwarded
as usual for an SR packet. As long as the packet travels within the as usual for an SR packet. As long as the packet travels within the
SR domain, no further HMAC check needs to be done. Subsequent SR domain, no further HMAC check needs to be done. Subsequent
routers in the SR domain MAY verify the HMAC TLV when they process routers in the SR domain MAY verify the HMAC TLV when they process
the SRH (i.e. when they are the destination). the SRH (i.e. when they are the destination).
If the validation fails, then this packet MUST be dropped, an ICMP If the validation fails, then this packet MUST be dropped, an ICMP
error message (parameter problem) SHOULD be generated (but rate error message (parameter problem) SHOULD be generated (but rate
limited) and SHOULD be logged. limited) and SHOULD be logged.
5.3.3. SR path exposure 6.3.3. SR path exposure
As the intermediate SR nodes addresses appears in the SRH, if this As the intermediate SR nodes addresses appears in the SRH, if this
SRH is visible to an outsider then he/she could reuse this knowledge SRH is visible to an outsider then he/she could reuse this knowledge
to launch an attack on the intermediate SR nodes or get some insider to launch an attack on the intermediate SR nodes or get some insider
knowledge on the topology. This is especially applicable when the knowledge on the topology. This is especially applicable when the
path between the source node and the first SR domain ingress router path between the source node and the first SR domain ingress router
is on the public Internet. is on the public Internet.
The first remark is to state that 'security by obscurity' is never The first remark is to state that 'security by obscurity' is never
enough; in other words, the security policy of the SR domain MUST enough; in other words, the security policy of the SR domain MUST
skipping to change at page 23, line 36 skipping to change at page 27, line 34
[RFC4303] cannot be use to protect the SRH as per RFC4303 the ESP [RFC4303] cannot be use to protect the SRH as per RFC4303 the ESP
header must appear after any routing header (including SRH). header must appear after any routing header (including SRH).
To prevent a user to leverage the gained knowledge by intercepting To prevent a user to leverage the gained knowledge by intercepting
SRH, it it recommended to apply an infrastructure Access Control List SRH, it it recommended to apply an infrastructure Access Control List
(iACL) at the edge of the SR domain. This iACL will drop all packets (iACL) at the edge of the SR domain. This iACL will drop all packets
from outside the SR-domain whose destination is any address of any from outside the SR-domain whose destination is any address of any
router inside the domain. This security policy should be tuned for router inside the domain. This security policy should be tuned for
local operations. local operations.
5.3.4. Impact of BCP-38 6.3.4. Impact of BCP-38
BCP-38 [RFC2827], also known as "Network Ingress Filtering", checks BCP-38 [RFC2827], also known as "Network Ingress Filtering", checks
whether the source address of packets received on an interface is whether the source address of packets received on an interface is
valid for this interface. The use of loose source routing such as valid for this interface. The use of loose source routing such as
SRH forces packets to follow a path which differs from the expected SRH forces packets to follow a path which differs from the expected
routing. Therefore, if BCP-38 was implemented in all routers inside routing. Therefore, if BCP-38 was implemented in all routers inside
the SR domain, then SR packets could be received by an interface the SR domain, then SR packets could be received by an interface
which is not expected one and the packets could be dropped. which is not expected one and the packets could be dropped.
As an SR domain is usually a subset of one administrative domain, and As an SR domain is usually a subset of one administrative domain, and
as BCP-38 is only deployed at the ingress routers of this as BCP-38 is only deployed at the ingress routers of this
administrative domain and as packets arriving at those ingress administrative domain and as packets arriving at those ingress
routers have been normally forwarded using the normal routing routers have been normally forwarded using the normal routing
information, then there is no reason why this ingress router should information, then there is no reason why this ingress router should
drop the SRH packet based on BCP-38. Routers inside the domain drop the SRH packet based on BCP-38. Routers inside the domain
commonly do not apply BCP-38; so, this is not a problem. commonly do not apply BCP-38; so, this is not a problem.
6. IANA Considerations 7. IANA Considerations
This document makes the following registrations in the Internet This document makes the following registrations in the Internet
Protocol Version 6 (IPv6) Parameters "Routing Type" registry Protocol Version 6 (IPv6) Parameters "Routing Type" registry
maintained by IANA: maintained by IANA:
Suggested Description Reference Suggested Description Reference
Value Value
---------------------------------------------------------- ----------------------------------------------------------
4 Segment Routing Header (SRH) This document 4 Segment Routing Header (SRH) This document
In addition, this document request IANA to create and maintain a new This document request IANA to create and maintain a new Registry:
Registry: "Segment Routing Header Type-Value Objects". The following "Segment Routing Header TLVs"
code-points are requested from the registry:
Registry: Segment Routing Header Type-Value Objects 7.1. Segment Routing Header TLVs Register
Suggested Description Reference This document requests the creation of a new IANA managed registry to
identify SRH TLVs. The registration procedure is "Expert Review" as
defined in [RFC5226]. Suggested registry name is "Segment Routing
Header TLVs". A TLV is identified through an unsigned 8 bit
codepoint value. The following codepoints are defined in this
document:
Suggested Description Reference
Value Value
----------------------------------------------------- -----------------------------------------------------
1 Ingress Node TLV This document 1 Ingress Node TLV This document
2 Egress Node TLV This document 2 Egress Node TLV This document
3 Opaque Container TLV This document 3 Opaque Container TLV This document
4 Padding TLV This document 4 Padding TLV This document
5 HMAC TLV This document 5 HMAC TLV This document
6 NSH Carrier TLV This document
7. Manageability Considerations 8. Manageability Considerations
TBD TBD
8. Contributors 9. Contributors
Dave Barach, John Leddy, John Brzozowski, Pierre Francois, Nagendra Dave Barach, John Brzozowski, Pierre Francois, Nagendra Kumar, Mark
Kumar, Mark Townsley, Christian Martin, Roberta Maglione, James Townsley, Christian Martin, Roberta Maglione, James Connolly, Aloys
Connolly, Aloys Augustin contributed to the content of this document. Augustin contributed to the content of this document.
9. Acknowledgements 10. Acknowledgements
The authors would like to thank Ole Troan, Bob Hinden, Fred Baker, The authors would like to thank Ole Troan, Bob Hinden, Fred Baker,
Brian Carpenter, Alexandru Petrescu and Punit Kumar Jaiswal for their Brian Carpenter, Alexandru Petrescu and Punit Kumar Jaiswal for their
comments to this document. comments to this document.
10. References 11. References
10.1. Normative References 11.1. Normative References
[FIPS180-4] [FIPS180-4]
National Institute of Standards and Technology, "FIPS National Institute of Standards and Technology, "FIPS
180-4 Secure Hash Standard (SHS)", March 2012, 180-4 Secure Hash Standard (SHS)", March 2012,
<http://csrc.nist.gov/publications/fips/fips180-4/ <http://csrc.nist.gov/publications/fips/fips180-4/
fips-180-4.pdf>. fips-180-4.pdf>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
skipping to change at page 25, line 37 skipping to change at page 29, line 37
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation [RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095, of Type 0 Routing Headers in IPv6", RFC 5095,
DOI 10.17487/RFC5095, December 2007, DOI 10.17487/RFC5095, December 2007,
<http://www.rfc-editor.org/info/rfc5095>. <http://www.rfc-editor.org/info/rfc5095>.
[RFC6407] Weis, B., Rowles, S., and T. Hardjono, "The Group Domain [RFC6407] Weis, B., Rowles, S., and T. Hardjono, "The Group Domain
of Interpretation", RFC 6407, DOI 10.17487/RFC6407, of Interpretation", RFC 6407, DOI 10.17487/RFC6407,
October 2011, <http://www.rfc-editor.org/info/rfc6407>. October 2011, <http://www.rfc-editor.org/info/rfc6407>.
10.2. Informative References 11.2. Informative References
[I-D.bashandy-isis-srv6-extensions]
Bashandy, A., Filsfils, C., Ginsberg, L., and B. Decraene,
"IS-IS Extensions to Support Segment Routing over IPv6
Dataplane", draft-bashandy-isis-srv6-extensions-00 (work
in progress), March 2017.
[I-D.dawra-bgp-srv6-vpn]
(Unknown), (., Dawra, G., Filsfils, C., Dukes, D.,
Brissette, P., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., daniel.bernier@bell.ca, d.,
Steinberg, D., Raszuk, R., Decraene, B., and S.
Matsushima, "BGP Signaling of IPv6-Segment-Routing-based
VPN Networks", draft-dawra-bgp-srv6-vpn-00 (work in
progress), March 2017.
[I-D.filsfils-spring-srv6-network-programming]
Filsfils, C., Leddy, J., daniel.voyer@bell.ca, d.,
daniel.bernier@bell.ca, d., Steinberg, D., Raszuk, R.,
Matsushima, S., Lebrun, D., Decraene, B., Peirens, B.,
Salsano, S., Naik, G., Elmalky, H., Jonnalagadda, P.,
Sharif, M., Ayyangar, A., Mynam, S., Bashandy, A., Raza,
K., Dukes, D., Clad, F., and P. Camarillo, "SRv6 Network
Programming", draft-filsfils-spring-srv6-network-
programming-00 (work in progress), March 2017.
[I-D.ietf-isis-l2bundles]
Ginsberg, L., Bashandy, A., Filsfils, C., Previdi, S.,
Nanduri, M., and E. Aries, "Advertising L2 Bundle Member
Link Attributes in IS-IS", draft-ietf-isis-l2bundles-03
(work in progress), February 2017.
[I-D.ietf-isis-segment-routing-extensions] [I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., Previdi, S., Filsfils, C., Bashandy, A., Gredler, H.,
Litkowski, S., Decraene, B., and j. jefftant@gmail.com, Litkowski, S., Decraene, B., and j. jefftant@gmail.com,
"IS-IS Extensions for Segment Routing", draft-ietf-isis- "IS-IS Extensions for Segment Routing", draft-ietf-isis-
segment-routing-extensions-09 (work in progress), October segment-routing-extensions-11 (work in progress), March
2016. 2017.
[I-D.ietf-ospf-ospfv3-segment-routing-extensions] [I-D.ietf-ospf-ospfv3-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H., Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3
Extensions for Segment Routing", draft-ietf-ospf-ospfv3- Extensions for Segment Routing", draft-ietf-ospf-ospfv3-
segment-routing-extensions-07 (work in progress), October segment-routing-extensions-09 (work in progress), March
2016. 2017.
[I-D.ietf-sfc-nsh]
Quinn, P. and U. Elzur, "Network Service Header", draft-
ietf-sfc-nsh-12 (work in progress), February 2017.
[I-D.ietf-spring-ipv6-use-cases] [I-D.ietf-spring-ipv6-use-cases]
Brzozowski, J., Leddy, J., Townsley, W., Filsfils, C., and Brzozowski, J., Leddy, J., Filsfils, C., Maglione, R., and
R. Maglione, "IPv6 SPRING Use Cases", draft-ietf-spring- W. Townsley, "IPv6 SPRING Use Cases", draft-ietf-spring-
ipv6-use-cases-08 (work in progress), January 2017. ipv6-use-cases-09 (work in progress), February 2017.
[I-D.ietf-spring-resiliency-use-cases] [I-D.ietf-spring-resiliency-use-cases]
Filsfils, C., Previdi, S., Decraene, B., and R. Shakir, Filsfils, C., Previdi, S., Decraene, B., and R. Shakir,
"Resiliency use cases in SPRING networks", draft-ietf- "Resiliency use cases in SPRING networks", draft-ietf-
spring-resiliency-use-cases-08 (work in progress), October spring-resiliency-use-cases-08 (work in progress), October
2016. 2016.
[I-D.ietf-spring-segment-routing] [I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Decraene, B., Litkowski, S., Filsfils, C., Previdi, S., Decraene, B., Litkowski, S.,
and R. Shakir, "Segment Routing Architecture", draft-ietf- and R. Shakir, "Segment Routing Architecture", draft-ietf-
spring-segment-routing-10 (work in progress), November spring-segment-routing-11 (work in progress), February
2016. 2017.
[I-D.ietf-spring-segment-routing-mpls] [I-D.ietf-spring-segment-routing-mpls]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Shakir, R., Litkowski, S., and R. Shakir, "Segment Routing with MPLS
jefftant@gmail.com, j., and E. Crabbe, "Segment Routing data plane", draft-ietf-spring-segment-routing-mpls-08
with MPLS data plane", draft-ietf-spring-segment-routing- (work in progress), March 2017.
mpls-06 (work in progress), January 2017.
[I-D.previdi-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Sreekantiah, A., Sivabalan, S.,
Mattes, P., Rosen, E., and S. Lin, "Advertising Segment
Routing Policies in BGP", draft-previdi-idr-segment-
routing-te-policy-05 (work in progress), February 2017.
[RFC1940] Estrin, D., Li, T., Rekhter, Y., Varadhan, K., and D. [RFC1940] Estrin, D., Li, T., Rekhter, Y., Varadhan, K., and D.
Zappala, "Source Demand Routing: Packet Format and Zappala, "Source Demand Routing: Packet Format and
Forwarding Specification (Version 1)", RFC 1940, Forwarding Specification (Version 1)", RFC 1940,
DOI 10.17487/RFC1940, May 1996, DOI 10.17487/RFC1940, May 1996,
<http://www.rfc-editor.org/info/rfc1940>. <http://www.rfc-editor.org/info/rfc1940>.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997, DOI 10.17487/RFC2104, February 1997,
skipping to change at page 27, line 5 skipping to change at page 31, line 44
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <http://www.rfc-editor.org/info/rfc2827>. May 2000, <http://www.rfc-editor.org/info/rfc2827>.
[RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/ [RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/
Co-existence Security Considerations", RFC 4942, Co-existence Security Considerations", RFC 4942,
DOI 10.17487/RFC4942, September 2007, DOI 10.17487/RFC4942, September 2007,
<http://www.rfc-editor.org/info/rfc4942>. <http://www.rfc-editor.org/info/rfc4942>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6 [RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554, for Low-Power and Lossy Networks (RPL)", RFC 6554,
DOI 10.17487/RFC6554, March 2012, DOI 10.17487/RFC6554, March 2012,
<http://www.rfc-editor.org/info/rfc6554>. <http://www.rfc-editor.org/info/rfc6554>.
[RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B.,
Litkowski, S., Horneffer, M., and R. Shakir, "Source Litkowski, S., Horneffer, M., and R. Shakir, "Source
Packet Routing in Networking (SPRING) Problem Statement Packet Routing in Networking (SPRING) Problem Statement
and Requirements", RFC 7855, DOI 10.17487/RFC7855, May and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
skipping to change at page 27, line 34 skipping to change at page 32, line 34
Email: sprevidi@cisco.com Email: sprevidi@cisco.com
Clarence Filsfils Clarence Filsfils
Cisco Systems, Inc. Cisco Systems, Inc.
Brussels Brussels
BE BE
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Kamran Raza
Cisco Systems, Inc.
Email: skraza@cisco.com
"Darren Dukes
Cisco Systems, Inc.
Email: ddukes@cisco.com
John Leddy
Comcast
4100 East Dry Creek Road
Centennial, CO 80122
US
Email: John_Leddy@comcast.com
Brian Field Brian Field
Comcast Comcast
4100 East Dry Creek Road 4100 East Dry Creek Road
Centennial, CO 80122 Centennial, CO 80122
US US
Email: Brian_Field@cable.comcast.com Email: Brian_Field@cable.comcast.com
Daniel Voyer
Bell Canada
Email: daniel.voyer@bell.ca
Daniel Bernier
Bell Canada
Email: daniel.bernier@bell.ca
Satoru Matsushima
Softbank
Email: satoru.matsushima@g.softbank.co.jp
Ida Leung Ida Leung
Rogers Communications Rogers Communications
8200 Dixie Road 8200 Dixie Road
Brampton, ON L6T 0C1 Brampton, ON L6T 0C1
CA CA
Email: Ida.Leung@rci.rogers.com Email: Ida.Leung@rci.rogers.com
Jen Linkova Jen Linkova
Google Google
1600 Amphitheatre Parkway 1600 Amphitheatre Parkway
skipping to change at line 1302 skipping to change at page 34, line 41
Email: evyncke@cisco.com Email: evyncke@cisco.com
David Lebrun David Lebrun
Universite Catholique de Louvain Universite Catholique de Louvain
Place Ste Barbe, 2 Place Ste Barbe, 2
Louvain-la-Neuve, 1348 Louvain-la-Neuve, 1348
Belgium Belgium
Email: david.lebrun@uclouvain.be Email: david.lebrun@uclouvain.be
Dirk Steinberg
Steinberg Consulting
Email: dws@dirksteinberg.de
Robert Raszuk
Bloomberg
Email: robert@raszuk.net
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