draft-ietf-teas-assoc-corouted-bidir-frr-05.txt   draft-ietf-teas-assoc-corouted-bidir-frr-06.txt 
TEAS Working Group R. Gandhi, Ed. TEAS Working Group R. Gandhi, Ed.
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Updates: 4090, 7551 H. Shah Updates: 4090, 7551 H. Shah
Intended Status: Standards Track Ciena Intended Status: Standards Track Ciena
Expires: February 9, 2019 J. Whittaker Expires: March 1, 2019 J. Whittaker
Verizon Verizon
August 8, 2018 August 28, 2018
Updates to the Fast Reroute Procedures for Updates to the Fast Reroute Procedures for
Co-routed Associated Bidirectional Label Switched Paths (LSPs) Co-routed Associated Bidirectional Label Switched Paths (LSPs)
draft-ietf-teas-assoc-corouted-bidir-frr-05 draft-ietf-teas-assoc-corouted-bidir-frr-06
Abstract Abstract
Resource Reservation Protocol (RSVP) association signaling can be Resource Reservation Protocol (RSVP) association signaling can be
used to bind two unidirectional LSPs into an associated bidirectional used to bind two unidirectional LSPs into an associated bidirectional
LSP. When an associated bidirectional LSP is co-routed, the reverse LSP. When an associated bidirectional LSP is co-routed, the reverse
LSP follows the same path as its forward LSP. This document updates LSP follows the same path as its forward LSP. This document updates
the Fast Reroute (FRR) procedures defined in RFC 4090 to support both the Fast Reroute (FRR) procedures defined in RFC 4090 to support both
single-sided and double-sided provisioned associated bidirectional single-sided and double-sided provisioned associated bidirectional
LSPs. This document also updates the procedure for associating two LSPs. This document also updates the procedure for associating two
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Conventions Used in This Document . . . . . . . . . . . . . . 3
1.1. Assumptions and Considerations . . . . . . . . . . . . . . 3 1.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 4 1.2.1. Forward Unidirectional LSPs . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2.2. Reverse Co-routed Unidirectional LSPs . . . . . . . . 3
2.2.1. Forward Unidirectional LSPs . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2.2. Reverse Co-routed Unidirectional LSPs . . . . . . . . 4 2.1. Assumptions and Considerations . . . . . . . . . . . . . . 4
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5 3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Fast Reroute Bypass Tunnel Assignment . . . . . . . . . . 5 3.1. Fast Reroute Bypass Tunnel Assignment . . . . . . . . . . 5
3.2. Node Protection Bypass Tunnels . . . . . . . . . . . . . . 6 3.2. Node Protection Bypass Tunnels . . . . . . . . . . . . . . 6
3.3. Bidirectional LSP Association At Mid-Points . . . . . . . 7 3.3. Bidirectional LSP Association At Mid-Points . . . . . . . 7
4. Signaling Procedure . . . . . . . . . . . . . . . . . . . . . 8 4. Signaling Procedure . . . . . . . . . . . . . . . . . . . . . 8
4.1. Associated Bidirectional LSP Fast Reroute . . . . . . . . 8 4.1. Associated Bidirectional LSP Fast Reroute . . . . . . . . 8
4.1.1. Restoring Co-routing with Node Protection Bypass 4.1.1. Restoring Co-routing with Node Protection Bypass
Tunnels . . . . . . . . . . . . . . . . . . . . . . . 9 Tunnels . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.2. Unidirectional Link Failures . . . . . . . . . . . . . 9 4.1.2. Unidirectional Link Failures . . . . . . . . . . . . . 9
4.1.3. Revertive Behavior after Fast Reroute . . . . . . . . 10 4.1.3. Revertive Behavior after Fast Reroute . . . . . . . . 10
4.1.4. Bypass Tunnel Provisioning . . . . . . . . . . . . . . 10 4.1.4. Bypass Tunnel Provisioning . . . . . . . . . . . . . . 10
4.1.5. One-to-One Bypass Tunnel . . . . . . . . . . . . . . . 10 4.1.5. One-to-One Bypass Tunnel . . . . . . . . . . . . . . . 10
4.2. Bidirectional LSP Association At Mid-points . . . . . . . 10 4.2. Bidirectional LSP Association At Mid-points . . . . . . . 11
5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
Appendix A. Extended ASSOCIATION ID . . . . . . . . . . . . . . . 11 Appendix A. Extended ASSOCIATION ID . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . . 14 8.1. Normative References . . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . . 14 8.2. Informative References . . . . . . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Conventions Used in This Document
1.1. Key Word Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Terminology
The reader is assumed to be familiar with the terminology defined in
[RFC2205], [RFC3209], [RFC4090], [RFC7551], and [RFC8271].
1.2.1. Forward Unidirectional LSPs
Two reverse unidirectional point-to-point (P2P) LSPs are setup in the
opposite directions between a pair of source and destination nodes to
form an associated bidirectional Label Switched Path (LSP). In the
case of single-sided provisioned LSP, the originating LSP with
REVERSE_LSP Object [RFC7551] is identified as a forward
unidirectional LSP. In the case of double-sided provisioned LSP, the
LSP originating from the higher node address (as source) and
terminating on the lower node address (as destination) is identified
as a forward unidirectional LSP.
1.2.2. Reverse Co-routed Unidirectional LSPs
Two reverse unidirectional point-to-point (P2P) LSPs are setup in the
opposite directions between a pair of source and destination nodes to
form an associated bidirectional Label Switched Path (LSP). A
reverse unidirectional LSP originates on the same node where the
forward unidirectional LSP terminates, and it terminates on the same
node where the forward unidirectional LSP originates. A reverse co-
routed unidirectional LSP traverses along the same path as the
forward direction unidirectional LSP in the opposite direction.
2. Introduction
The Resource Reservation Protocol (RSVP) (Extended) ASSOCIATION The Resource Reservation Protocol (RSVP) (Extended) ASSOCIATION
Object is specified in [RFC6780] which can be used generically to Object is specified in [RFC6780] which can be used generically to
associate Multiprotocol Label Switching (MPLS) and Generalized MPLS associate Multiprotocol Label Switching (MPLS) and Generalized MPLS
(GMPLS) Traffic Engineering (TE) Label Switched Paths (LSPs). (GMPLS) Traffic Engineering (TE) Label Switched Paths (LSPs).
[RFC7551] defines mechanisms for binding two point-to-point [RFC7551] defines mechanisms for binding two point-to-point
unidirectional LSPs [RFC3209] into an associated bidirectional LSP. unidirectional LSPs [RFC3209] into an associated bidirectional LSP.
There are two models described in [RFC7551] for provisioning an There are two models described in [RFC7551] for provisioning an
associated bidirectional LSP, single-sided and double-sided. In both associated bidirectional LSP, single-sided and double-sided. In both
models, the reverse LSP of the bidirectional LSP may or may not be models, the reverse LSP of the bidirectional LSP may or may not be
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coordinate bypass tunnel assignments in the forward and reverse coordinate bypass tunnel assignments in the forward and reverse
directions of the LSP. The mechanisms defined in [RFC8271] are also directions of the LSP. The mechanisms defined in [RFC8271] are also
useful for the FRR of associated bidirectional LSPs. useful for the FRR of associated bidirectional LSPs.
This document updates the FRR procedures defined in [RFC4090] to This document updates the FRR procedures defined in [RFC4090] to
support both single-sided and double-sided provisioned associated support both single-sided and double-sided provisioned associated
bidirectional LSPs. This document also updates the procedure for bidirectional LSPs. This document also updates the procedure for
associating two reverse LSPs defined in [RFC7551] to support associating two reverse LSPs defined in [RFC7551] to support
co-routed bidirectional LSPs. The FRR procedures can ensure that for co-routed bidirectional LSPs. The FRR procedures can ensure that for
the co-routed LSPs, traffic flows on co-routed paths in the forward the co-routed LSPs, traffic flows on co-routed paths in the forward
and reverse directions after a failure event. and reverse directions after fast reroute.
1.1. Assumptions and Considerations 2.1. Assumptions and Considerations
The following assumptions and considerations apply to this document: The following assumptions and considerations apply to this document:
o The FRR procedure for the unidirectional LSPs is defined in o The FRR procedure for the unidirectional LSPs is defined in
[RFC4090] and is not modified by this document. [RFC4090] and is not modified by this document.
o The FRR procedure when using the unidirectional bypass tunnels is o The FRR procedure when using the unidirectional bypass tunnels is
defined in [RFC4090] and is not modified by this document. defined in [RFC4090] and is not modified by this document.
o This document assumes that the FRR bypass tunnels used for o This document assumes that the FRR bypass tunnels used for
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defined in this document may be used for protected non-corouted defined in this document may be used for protected non-corouted
associated bidirectional LSPs but requires that the downstream associated bidirectional LSPs but requires that the downstream
Point of Local Repair (PLR) and Merge Point (MP) pair of the Point of Local Repair (PLR) and Merge Point (MP) pair of the
forward LSP matches the upstream MP and PLR pair of the reverse forward LSP matches the upstream MP and PLR pair of the reverse
LSP. LSP.
o Unless otherwise specified in this document, the fast reroute o Unless otherwise specified in this document, the fast reroute
procedures defined in [RFC4090] are used for associated procedures defined in [RFC4090] are used for associated
bidirectional LSPs. bidirectional LSPs.
2. Conventions Used in This Document
2.1. Key Word Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2.2. Terminology
The reader is assumed to be familiar with the terminology defined in
[RFC2205], [RFC3209], [RFC4090], [RFC7551], and [RFC8271].
2.2.1. Forward Unidirectional LSPs
Two reverse unidirectional point-to-point (P2P) LSPs are setup in the
opposite directions between a pair of source and destination nodes to
form an associated bidirectional LSP. In the case of single-sided
provisioned LSP, the originating LSP with REVERSE_LSP Object is
identified as a forward unidirectional LSP. In the case of double-
sided provisioned LSP, the LSP originating from the higher node
address (as source) and terminating on the lower node address (as
destination) is identified as a forward unidirectional LSP.
2.2.2. Reverse Co-routed Unidirectional LSPs
Two reverse unidirectional point-to-point (P2P) LSPs are setup in the
opposite directions between a pair of source and destination nodes to
form an associated bidirectional LSP. A reverse unidirectional LSP
originates on the same node where the forward unidirectional LSP
terminates, and it terminates on the same node where the forward
unidirectional LSP originates. A reverse co-routed unidirectional
LSP traverses along the same path as the forward direction
unidirectional LSP in the opposite direction.
3. Problem Statement 3. Problem Statement
As specified in [RFC7551], in the single-sided provisioning case, the As specified in [RFC7551], in the single-sided provisioning case, the
RSVP TE tunnel is configured only on one endpoint node of the RSVP TE tunnel is configured only on one endpoint node of the
bidirectional LSP. An LSP for this tunnel is initiated by the bidirectional LSP. An LSP for this tunnel is initiated by the
originating endpoint with (Extended) ASSOCIATION Object containing originating endpoint with (Extended) ASSOCIATION Object containing
Association Type set to "single-sided associated bidirectional LSP" Association Type set to "single-sided associated bidirectional LSP"
and REVERSE_LSP Object inserted in the RSVP Path message. The remote and REVERSE_LSP Object inserted in the RSVP Path message. The remote
endpoint then creates the corresponding reverse TE tunnel and signals endpoint then creates the corresponding reverse TE tunnel and signals
the reverse LSP in response using the information from the the reverse LSP in response using the information from the
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o For double-sided provisioned bidirectional LSPs [RFC7551], both o For double-sided provisioned bidirectional LSPs [RFC7551], both
endpoints need to ensure that the bidirectional LSP has a unique endpoints need to ensure that the bidirectional LSP has a unique
Extended ASSOCIATION Object for each forward and reverse LSP pair Extended ASSOCIATION Object for each forward and reverse LSP pair
by selecting appropriate unique Extended Association IDs signaled by selecting appropriate unique Extended Association IDs signaled
by them. by them.
5. Compatibility 5. Compatibility
This document updates the procedures for fast reroute for associated This document updates the procedures for fast reroute for associated
bidirectional LSPs defined in [RFC4090] and for associating bidirectional LSPs defined in [RFC4090] and for associating
bidirectional LSPs defined in [RFC7551]. Operators wishing to use bidirectional LSPs defined in [RFC7551]. The procedures use the
this function SHOULD ensure that it is supported on all the nodes on signaling messages defined in [RFC8271] and no new signaling messages
the LSP path. No new signaling messages are defined in this are defined in this document. The procedures ensure that for the co-
document. routed LSPs, traffic flows on co-routed paths in the forward and
reverse directions after fast reroute. Operators wishing to use this
function SHOULD ensure that it is supported on all the nodes on the
LSP path. The nodes not supporting this function can cause the
traffic to flow on asymmetric paths in the forward and reverse
directions of the associated bidirectional LSPs after fast reroute.
6. Security Considerations 6. Security Considerations
This document updates the signaling mechanisms defined in [RFC4090] This document updates the signaling mechanisms defined in [RFC4090]
and [RFC7551]; and does not introduce any additional security and [RFC7551]; and does not introduce any additional security
considerations other than those already covered in [RFC4090], considerations other than those already covered in [RFC4090],
[RFC7551], [RFC8271], and the MPLS/GMPLS security framework [RFC7551], [RFC8271], and the MPLS/GMPLS security framework
[RFC5920]. [RFC5920].
7. IANA Considerations 7. IANA Considerations
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4561, June 2006. 4561, June 2006.
[RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP [RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP
Association Object Extensions", RFC 6780, October 2012. Association Object Extensions", RFC 6780, October 2012.
[RFC7551] Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE [RFC7551] Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE
Extensions for Associated Bidirectional Label Switched Extensions for Associated Bidirectional Label Switched
Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015, Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015,
<https://www.rfc-editor.org/info/rfc7551>. <https://www.rfc-editor.org/info/rfc7551>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8271] Taillon, M., Saad, T., Ed., Gandhi, R., Ed., Ali, Z., and [RFC8271] Taillon, M., Saad, T., Ed., Gandhi, R., Ed., Ali, Z., and
M. Bhatia, "Updates to Resource Reservation Protocol for M. Bhatia, "Updates to Resource Reservation Protocol for
Fast Reroute of Traffic Engineering GMPLS Label Switched Fast Reroute of Traffic Engineering GMPLS Label Switched
Paths (LSPs)", RFC 8271, October 2017. Paths (LSPs)", RFC 8271, October 2017.
8.2. Informative References 8.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001. Tunnels", RFC 3209, December 2001.
 End of changes. 12 change blocks. 
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