draft-ietf-rtgwg-ipfrr-framework-08.txt   draft-ietf-rtgwg-ipfrr-framework-09.txt 
Network Working Group M. Shand Network Working Group M. Shand
Internet-Draft S. Bryant Internet-Draft S. Bryant
Intended status: Informational Cisco Systems Intended status: Informational Cisco Systems
Expires: August 28, 2008 February 25, 2008 Expires: May 3, 2009 October 30, 2008
IP Fast Reroute Framework IP Fast Reroute Framework
draft-ietf-rtgwg-ipfrr-framework-08.txt draft-ietf-rtgwg-ipfrr-framework-09
Status of this Memo Status of this Memo
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on August 28, 2008. This Internet-Draft will expire on May 3, 2009.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract Abstract
This document provides a framework for the development of IP fast- This document provides a framework for the development of IP fast-
reroute mechanisms which provide protection against link or router reroute mechanisms which provide protection against link or router
failure by invoking locally determined repair paths. Unlike MPLS failure by invoking locally determined repair paths. Unlike MPLS
Fast-reroute, the mechanisms are applicable to a network employing Fast-reroute, the mechanisms are applicable to a network employing
conventional IP routing and forwarding. An essential part of such conventional IP routing and forwarding. An essential part of such
mechanisms is the prevention of packet loss caused by the loops which mechanisms is the prevention of packet loss caused by the loops which
normally occur during the re-convergence of the network following a normally occur during the re-convergence of the network following a
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2. Loop free alternate paths. Such a path exists when a direct 2. Loop free alternate paths. Such a path exists when a direct
neighbor of the router adjacent to the failure has a path to the neighbor of the router adjacent to the failure has a path to the
destination which can be guaranteed not to traverse the failure. destination which can be guaranteed not to traverse the failure.
3. Multi-hop repair paths. When there is no feasible loop free 3. Multi-hop repair paths. When there is no feasible loop free
alternate path it may still be possible to locate a router, which alternate path it may still be possible to locate a router, which
is more than one hop away from the router adjacent to the is more than one hop away from the router adjacent to the
failure, from which traffic will be forwarded to the destination failure, from which traffic will be forwarded to the destination
without traversing the failure. without traversing the failure.
ECMP and loop free alternate paths (as described in ECMP and loop free alternate paths (as described in [RFC5286]) offer
[I-D.ietf-rtgwg-ipfrr-spec-base]) offer the simplest repair paths and the simplest repair paths and would normally be used when they are
would normally be used when they are available. It is anticipated available. It is anticipated that around 80% of failures (see
that around 80% of failures (see Section 4.2.2) can be repaired using Section 4.2.2) can be repaired using these basic methods alone.
these basic methods alone.
Multi-hop repair paths are more complex, both in the computations Multi-hop repair paths are more complex, both in the computations
required to determine their existence, and in the mechanisms required required to determine their existence, and in the mechanisms required
to invoke them. They can be further classified as: to invoke them. They can be further classified as:
1. Mechanisms where one or more alternate FIBs are pre-computed in 1. Mechanisms where one or more alternate FIBs are pre-computed in
all routers and the repaired packet is instructed to be forwarded all routers and the repaired packet is instructed to be forwarded
using a "repair FIB" by some method of per packet signaling such using a "repair FIB" by some method of per packet signaling such
as detecting a "U-turn" [I-D.atlas-ip-local-protect-uturn] , as detecting a "U-turn" [I-D.atlas-ip-local-protect-uturn] ,
[FIFR] or by marking the packet [SIMULA]. [FIFR] or by marking the packet [SIMULA].
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draft-atlas-ip-local-protect-uturn-03 (work in progress), draft-atlas-ip-local-protect-uturn-03 (work in progress),
March 2006. March 2006.
[I-D.bryant-ipfrr-tunnels] [I-D.bryant-ipfrr-tunnels]
Bryant, S., Filsfils, C., Previdi, S., and M. Shand, "IP Bryant, S., Filsfils, C., Previdi, S., and M. Shand, "IP
Fast Reroute using tunnels", draft-bryant-ipfrr-tunnels-03 Fast Reroute using tunnels", draft-bryant-ipfrr-tunnels-03
(work in progress), November 2007. (work in progress), November 2007.
[I-D.ietf-bfd-base] [I-D.ietf-bfd-base]
Katz, D. and D. Ward, "Bidirectional Forwarding Katz, D. and D. Ward, "Bidirectional Forwarding
Detection", draft-ietf-bfd-base-07 (work in progress), Detection", draft-ietf-bfd-base-08 (work in progress),
January 2008. March 2008.
[I-D.ietf-rtgwg-ipfrr-notvia-addresses] [I-D.ietf-rtgwg-ipfrr-notvia-addresses]
Bryant, S., "IP Fast Reroute Using Not-via Addresses", Shand, M., Bryant, S., and S. Previdi, "IP Fast Reroute
draft-ietf-rtgwg-ipfrr-notvia-addresses-01 (work in Using Not-via Addresses",
progress), July 2007. draft-ietf-rtgwg-ipfrr-notvia-addresses-02 (work in
progress), February 2008.
[I-D.ietf-rtgwg-ipfrr-spec-base]
Atlas, A., Zinin, A., Torvi, R., Choudhury, G., Martin,
C., Imhoff, B., and D. Fedyk, "Basic Specification for IP
Fast-Reroute: Loop-free Alternates",
draft-ietf-rtgwg-ipfrr-spec-base-10 (work in progress),
November 2007.
[I-D.ietf-rtgwg-lf-conv-frmwk] [I-D.ietf-rtgwg-lf-conv-frmwk]
Shand, M. and S. Bryant, "A Framework for Loop-free Shand, M. and S. Bryant, "A Framework for Loop-free
Convergence", draft-ietf-rtgwg-lf-conv-frmwk-02 (work in Convergence", draft-ietf-rtgwg-lf-conv-frmwk-02 (work in
progress), February 2008. progress), February 2008.
[I-D.tian-frr-alt-shortest-path] [I-D.tian-frr-alt-shortest-path]
Tian, A., "Fast Reroute using Alternative Shortest Paths", Tian, A., "Fast Reroute using Alternative Shortest Paths",
draft-tian-frr-alt-shortest-path-01 (work in progress), draft-tian-frr-alt-shortest-path-01 (work in progress),
July 2004. July 2004.
[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute [RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
Extensions to RSVP-TE for LSP Tunnels", RFC 4090, Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005. May 2005.
[SIMULA] Lysne, O., Kvalbein, A., Cicic, T., Gjessing, S., and A. [RFC5286] Atlas, A. and A. Zinin, "Basic Specification for IP Fast
Reroute: Loop-Free Alternates", RFC 5286, September 2008.
[SIMULA] Lysne, O., Kvalbein, A., Cicic, T., Gjessing, S., and A.
Hansen, "Fast IP Network Recovery using Multiple Routing Hansen, "Fast IP Network Recovery using Multiple Routing
Configurations."", Infocom 10.1109/INFOCOM.2006.227, 2006, Configurations."", Infocom 10.1109/INFOCOM.2006.227, 2006,
<http://folk.uio.no/amundk/infocom06.pdf>. <http://folk.uio.no/amundk/infocom06.pdf>.
Authors' Addresses Authors' Addresses
Mike Shand Mike Shand
Cisco Systems Cisco Systems
250, Longwater Avenue. 250, Longwater Avenue.
Reading, Berks RG2 6GB Reading, Berks RG2 6GB
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attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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