Operational Management of Loop-Free Alternates
RFC 7916
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RFC - Proposed Standard
(July 2016; No errata)
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Last updated |
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2016-07-11
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Replaces |
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draft-litkowski-rtgwg-lfa-manageability
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IETF
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plain text
pdf
html
bibtex
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WG state
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Submitted to IESG for Publication
(wg milestone:
Jul 2015 - Submit Operational M...
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Document shepherd |
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Jeff Tantsura
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Shepherd write-up |
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Show
(last changed 2015-05-04)
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| IESG |
IESG state |
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RFC 7916 (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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Send notices to |
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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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IANA action state |
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No IC
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Internet Engineering Task Force (IETF) S. Litkowski, Ed.
Request for Comments: 7916 B. Decraene
Category: Standards Track Orange
ISSN: 2070-1721 C. Filsfils
K. Raza
Cisco Systems
M. Horneffer
Deutsche Telekom
P. Sarkar
Individual Contributor
July 2016
Operational Management of Loop-Free Alternates
Abstract
Loop-Free Alternates (LFAs), as defined in RFC 5286, constitute an IP
Fast Reroute (IP FRR) mechanism enabling traffic protection for IP
traffic (and, by extension, MPLS LDP traffic). Following early
deployment experiences, this document provides operational feedback
on LFAs, highlights some limitations, and proposes a set of
refinements to address those limitations. It also proposes required
management specifications.
This proposal is also applicable to remote-LFA solutions.
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
http://www.rfc-editor.org/info/rfc7916.
Litkowski, et al. Standards Track [Page 1]
RFC 7916 LFA Manageability July 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
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.
Litkowski, et al. Standards Track [Page 2]
RFC 7916 LFA Manageability July 2016
Table of Contents
1. Introduction ....................................................4
1.1. Requirements Language ......................................4
2. Definitions .....................................................4
3. Operational Issues with Default LFA Tiebreakers .................5
3.1. Case 1: PE Router Protecting against Failures
within Core Network ........................................5
3.2. Case 2: PE Router Chosen to Protect against Core
Failures while P Router LFA Exists .........................7
3.3. Case 3: Suboptimal P Router Alternate Choice ...............8
3.4. Case 4: No-Transit LFA Computing Node ......................9
4. Need for Coverage Monitoring ....................................9
5. Need for LFA Activation Granularity ............................10
6. Configuration Requirements .....................................11
6.1. LFA Enabling/Disabling Scope ..............................11
6.2. Policy-Based LFA Selection ................................12
6.2.1. Connected versus Remote Alternates .................12
6.2.2. Mandatory Criteria .................................13
6.2.3. Additional Criteria ................................14
6.2.4. Evaluation of Criteria .............................14
6.2.5. Retrieving Alternate Path Attributes ...............18
6.2.6. ECMP LFAs ..........................................23
7. Operational Aspects ............................................24
7.1. No-Transit Condition on LFA Computing Node ................24
7.2. Manual Triggering of FRR ..................................25
7.3. Required Local Information ................................26
7.4. Coverage Monitoring .......................................26
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