Clarifying Procedures for Establishing BFD Sessions for MPLS Label Switched Paths (LSPs)
RFC 7726
| Document | Type |
RFC - Proposed Standard
(January 2016; No errata)
Updates RFC 5884
|
|
|---|---|---|---|
| Last updated | 2016-01-29 | ||
| Replaces | draft-grmas-bfd-rfc5884-clarifications | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Jeffrey Haas | ||
| Shepherd write-up | Show (last changed 2015-09-01) | ||
| IESG | IESG state | RFC 7726 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Alvaro Retana | ||
| Send notices to | aretana@cisco.com | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | No IC | ||
Internet Engineering Task Force (IETF) V. Govindan
Request for Comments: 7726 K. Rajaraman
Updates: 5884 Cisco Systems
Category: Standards Track G. Mirsky
ISSN: 2070-1721 Ericsson
N. Akiya
Big Switch Networks
S. Aldrin
Google
January 2016
Clarifying Procedures for Establishing BFD Sessions for
MPLS Label Switched Paths (LSPs)
Abstract
This document clarifies the procedures for establishing, maintaining,
and removing multiple, concurrent BFD (Bidirectional Forwarding
Detection) sessions for a given <MPLS LSP, FEC> as described in RFC
5884.
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 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7726.
Govindan, et al. Standards Track [Page 1]
RFC 7726 Clarifications to RFC 5884 January 2016
Copyright Notice
Copyright (c) 2016 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
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Table of Contents
1. Background . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 3
2.1. Procedures for Establishment of Multiple BFD Sessions . . 3
2.2. Procedures for Maintenance of Multiple BFD Sessions . . . 4
2.3. Procedures for Removing BFD Sessions at the Egress LSR . 4
2.4. Changing Discriminators for a BFD Session . . . . . . . . 5
3. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Normative References . . . . . . . . . . . . . . . . . . 6
5.2. Informative References . . . . . . . . . . . . . . . . . 6
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Background
[RFC5884] defines the procedures to bootstrap and maintain BFD
sessions for an <MPLS LSP, FEC> using a Label Switched Path (LSP)
ping. While Section 4 of [RFC5884] specifies that multiple BFD
sessions can be established for an <MPLS LSP, FEC> tuple, the
procedures to bootstrap and maintain multiple BFD sessions
concurrently over an <MPLS LSP, FEC> are not clearly specified.
Additionally, the procedures of removing BFD sessions bootstrapped on
the egress Label Switching Router (LSR) are unclear. This document
provides those clarifications without deviating from the principles
outlined in [RFC5884].
Govindan, et al. Standards Track [Page 2]
RFC 7726 Clarifications to RFC 5884 January 2016
The ability for an ingress LSR to establish multiple BFD sessions for
an <MPLS LSP, FEC> tuple is useful in scenarios such as LSPs based on
Segment Routing [SEG-ROUTING] or LSPs having Equal-Cost Multipath
(ECMP). The process used by the ingress LSR to determine the number
of BFD session(s) to be bootstrapped for an <MPLS LSP, FEC> tuple and
the mechanism used to construct those session(s) are outside the
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