Updates to the Fast Reroute Procedures for Co-routed Associated Bidirectional Label Switched Paths (LSPs)
RFC 8537
Internet Engineering Task Force (IETF) R. Gandhi, Ed.
Request for Comments: 8537 Cisco Systems, Inc.
Updates: 4090, 7551 H. Shah
Category: Standards Track Ciena
ISSN: 2070-1721 J. Whittaker
Verizon
February 2019
Updates to the Fast Reroute Procedures for Co-routed Associated
Bidirectional Label Switched Paths (LSPs)
Abstract
Resource Reservation Protocol (RSVP) association signaling can be
used to bind two unidirectional Label Switched Paths (LSPs) into an
associated bidirectional LSP. When an associated bidirectional LSP
is co-routed, the reverse LSP follows the same path as its forward
LSP. This document updates the fast reroute procedures defined in
RFC 4090 to support both single-sided and double-sided provisioned
associated bidirectional LSPs. This document also updates the
procedure for associating two reverse LSPs defined in RFC 7551 to
support co-routed bidirectional LSPs. The fast reroute procedures
can ensure that, for the co-routed LSPs, traffic flows on co-routed
paths in the forward and reverse directions after a failure event.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8537.
Gandhi, et al. Standards Track [Page 1]
RFC 8537 Associated Bidirectional LSP Fast Reroute February 2019
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
1.1. Assumptions and Considerations .............................4
2. Conventions Used in This Document ...............................4
2.1. Key Word Definitions .......................................4
2.2. Terminology ................................................4
2.2.1. Forward Unidirectional LSPs .........................5
2.2.2. Reverse Co-routed Unidirectional LSPs ...............5
3. Problem Statement ...............................................5
3.1. Fast Reroute Bypass Tunnel Assignment ......................6
3.2. Node Protection Bypass Tunnels .............................6
3.3. Bidirectional LSP Association at Midpoints .................7
4. Signaling Procedure .............................................8
4.1. Associated Bidirectional LSP Fast Reroute ..................8
4.1.1. Restoring Co-routing with Node Protection
Bypass Tunnels ......................................9
4.1.2. Unidirectional Link Failures .......................10
4.1.3. Revertive Behavior after Fast Reroute ..............10
4.1.4. Bypass Tunnel Provisioning .........................10
4.1.5. One-to-One Bypass Tunnel ...........................11
4.2. Bidirectional LSP Association at Midpoints ................11
5. Compatibility ..................................................11
6. Security Considerations ........................................12
7. IANA Considerations ............................................12
8. References .....................................................12
8.1. Normative References ......................................12
8.2. Informative References ....................................13
Appendix A. Extended Association ID ..............................14
Acknowledgments ...................................................16
Authors' Addresses ................................................16
Gandhi, et al. Standards Track [Page 2]
Show full document text