IP Fast Reroute Framework
RFC 5714
Document | Type | RFC - Informational (January 2010; No errata) | |
---|---|---|---|
Authors | Mike Shand , Stewart Bryant | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5714 (Informational) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ross Callon | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) M. Shand Request for Comments: 5714 S. Bryant Category: Informational Cisco Systems ISSN: 2070-1721 January 2010 IP Fast Reroute Framework Abstract This document provides a framework for the development of IP fast- reroute mechanisms that provide protection against link or router failure by invoking locally determined repair paths. Unlike MPLS fast-reroute, the mechanisms are applicable to a network employing conventional IP routing and forwarding. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. 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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see 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/rfc5714. Copyright Notice Copyright (c) 2010 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. Shand & Bryant Informational [Page 1] RFC 5714 IP Fast Reroute Framework January 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Scope and Applicability . . . . . . . . . . . . . . . . . . . 5 4. Problem Analysis . . . . . . . . . . . . . . . . . . . . . . . 5 5. Mechanisms for IP Fast-Reroute . . . . . . . . . . . . . . . . 7 5.1. Mechanisms for Fast Failure Detection . . . . . . . . . . 7 5.2. Mechanisms for Repair Paths . . . . . . . . . . . . . . . 8 5.2.1. Scope of Repair Paths . . . . . . . . . . . . . . . . 9 5.2.2. Analysis of Repair Coverage . . . . . . . . . . . . . 9 5.2.3. Link or Node Repair . . . . . . . . . . . . . . . . . 10 5.2.4. Maintenance of Repair Paths . . . . . . . . . . . . . 10 5.2.5. Local Area Networks . . . . . . . . . . . . . . . . . 11 5.2.6. Multiple Failures and Shared Risk Link Groups . . . . 11 5.3. Mechanisms for Micro-Loop Prevention . . . . . . . . . . . 12 6. Management Considerations . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13 9. Informative References . . . . . . . . . . . . . . . . . . . . 14 1. Introduction When a link or node failure occurs in a routed network, there is inevitably a period of disruption to the delivery of traffic until the network re-converges on the new topology. Packets for destinations that were previously reached by traversing the failed component may be dropped or may suffer looping. Traditionally, such disruptions have lasted for periods of at least several seconds, and most applications have been constructed to tolerate such a quality of service. Recent advances in routers have reduced this interval to under a second for carefully configured networks using link state IGPs. However, new Internet services are emerging that may be sensitive to periods of traffic loss that are orders of magnitude shorter than this. Addressing these issues is difficult because the distributed nature of the network imposes an intrinsic limit on the minimum convergence time that can be achieved. However, there is an alternative approach, which is to compute backup routes that allow the failure to be repaired locally by the router(s) detecting the failure without the immediate need to inform other routers of the failure. In this case, the disruption time can be limited to the small time taken to detect the adjacent failure and invoke the backup routes. This is analogous to the technique Shand & Bryant Informational [Page 2]Show full document text