Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)
RFC 7490
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RFC - Proposed Standard
(April 2015; No errata)
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Last updated |
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2015-10-14
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Replaces |
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draft-shand-remote-lfa
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IETF
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plain text
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htmlized
bibtex
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WG state
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Submitted to IESG for Publication
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Document shepherd |
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Alvaro Retana
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Shepherd write-up |
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Show
(last changed 2014-09-29)
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| IESG |
IESG state |
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RFC 7490 (Proposed Standard)
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Consensus Boilerplate |
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Yes
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Telechat date |
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Responsible AD |
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Alia Atlas
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(None)
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| IANA |
IANA review state |
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Version Changed - Review Needed
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No IANA Actions
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Internet Engineering Task Force (IETF) S. Bryant
Request for Comments: 7490 C. Filsfils
Category: Standards Track S. Previdi
ISSN: 2070-1721 Cisco Systems
M. Shand
Independent Contributor
N. So
Vinci Systems
April 2015
Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)
Abstract
This document describes an extension to the basic IP fast reroute
mechanism, described in RFC 5286, that provides additional backup
connectivity for point-to-point link failures when none can be
provided by the basic mechanisms.
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/rfc7490.
Copyright Notice
Copyright (c) 2015 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
(http://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.
Bryant, et al. Standards Track [Page 1]
RFC 7490 Remote LFA FRR April 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
3. Overview of Solution . . . . . . . . . . . . . . . . . . . . 4
4. Repair Paths . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Tunnels as Repair Paths . . . . . . . . . . . . . . . . . 6
4.2. Tunnel Requirements . . . . . . . . . . . . . . . . . . . 7
5. Construction of Repair Paths . . . . . . . . . . . . . . . . 8
5.1. Identifying Required Tunneled Repair Paths . . . . . . . 8
5.2. Determining Tunnel Endpoints . . . . . . . . . . . . . . 8
5.2.1. Computing Repair Paths . . . . . . . . . . . . . . . 9
5.2.2. Selecting Repair Paths . . . . . . . . . . . . . . . 11
5.3. A Cost-Based RLFA Algorithm . . . . . . . . . . . . . . . 12
5.4. Interactions with IS-IS Overload, RFC 6987, and Costed
Out Links . . . . . . . . . . . . . . . . . . . . . . . . 17
6. Example Application of Remote LFAs . . . . . . . . . . . . . 17
7. Node Failures . . . . . . . . . . . . . . . . . . . . . . . . 18
8. Operation in an LDP Environment . . . . . . . . . . . . . . . 19
9. Analysis of Real World Topologies . . . . . . . . . . . . . . 21
9.1. Topology Details . . . . . . . . . . . . . . . . . . . . 21
9.2. LFA Only . . . . . . . . . . . . . . . . . . . . . . . . 22
9.3. RLFA . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.4. Comparison of LFA and RLFA results . . . . . . . . . . . 24
10. Management and Operational Considerations . . . . . . . . . . 25
11. Historical Note . . . . . . . . . . . . . . . . . . . . . . . 25
12. Security Considerations . . . . . . . . . . . . . . . . . . . 25
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
13.1. Normative References . . . . . . . . . . . . . . . . . . 26
13.2. Informative References . . . . . . . . . . . . . . . . . 26
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
Bryant, et al. Standards Track [Page 2]
RFC 7490 Remote LFA FRR April 2015
1. Introduction
RFC 5714 [RFC5714] describes a framework for IP Fast Reroute (IPFRR)
and provides a summary of various proposed IPFRR solutions. A basic
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