Preferred Path Loop-Free Alternate (pLFA)

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Document Type Expired Internet-Draft (individual)
Authors Stewart Bryant  , Uma Chunduri  , Toerless Eckert 
Last updated 2021-06-25 (latest revision 2020-12-22)
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Fast re-route (FRR) is a technique that allows productive forwarding to continue in a network after a failure has occurred, but before the network has has time to re-converge. This is achieved by forwarding a packet on an alternate path that will not result in the packet looping. Preferred Path Routing (PPR) provides a method of injecting explicit paths into the routing protocol. The use of PPR to support FRR has a number of advantages. This document describes the advantages of using PPR to provide a loop-free alternate FRR path, and provides a framework for its use in this application.


Stewart Bryant (
Uma Chunduri (
Toerless Eckert (

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