No Further Fast Reroute
draft-kompella-mpls-nffrr-00

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MPLS WG                                                      K. Kompella
Internet-Draft                                                    W. Lin
Intended status: Standards Track                        Juniper Networks
Expires: September 9, 2020                                March 08, 2020

                        No Further Fast Reroute
                      draft-kompella-mpls-nffrr-00

Abstract

   There are several cases where, once Fast Reroute has taken place (for
   MPLS protection), a second fast reroute is undesirable, even
   detrimental.  This memo gives several examples of this, and proposes
   a mechanism to prevent further fast reroutes.

Status of This Memo

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Kompella & Lin          Expires September 9, 2020               [Page 1]
Internet-Draft                    NFFRR                       March 2020

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  EVPN (VPN/VPLS) Active-active Multihoming . . . . . . . .   3
     2.2.  RMR Protection  . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  General MPLS forwarding . . . . . . . . . . . . . . . . .   4
   3.  Solution  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  NFFRR for MPLS forwarding . . . . . . . . . . . . . . . .   6
     3.2.  Proposal  . . . . . . . . . . . . . . . . . . . . . . . .   8
       3.2.1.  NFFRR and SPRING  . . . . . . . . . . . . . . . . . .  10
     3.3.  NFFRR for MPLS Services . . . . . . . . . . . . . . . . .  10
     3.4.  NFFRR for RMR . . . . . . . . . . . . . . . . . . . . . .  11
   4.  Signaling NFFRR Capability  . . . . . . . . . . . . . . . . .  12
     4.1.  Signaling NFFRR Capability for MPLS Services with BGP . .  12
     4.2.  Signaling NFFRR Capability for MPLS Services with
           Targeted LDP  . . . . . . . . . . . . . . . . . . . . . .  12
     4.3.  Signaling NFFRR Capability for MPLS Forwarding  . . . . .  12
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   MPLS Fast Reroute (FRR) [RFC4090] [RFC5286] [RFC7490] is a useful and
   widely deployed tool for minimizing packet loss in the case of a link
   or node failure.  This has not only proven to be very effective, it
   is often the reason for using MPLS as a data plane.  FRR works for a
   variety of control plane protocols, including LDP, RSVP-TE, and
   SPRING.  Furthermore, FRR is often used to protect MPLS services such
   as IP VPN and EVPN.

   Having said this, there are case where, once FRR has taken place, if
   the packet encounters a second failure, a second FRR is not helpful,
   perhaps even disruptive.  For example, the packet may loop until TTL
   expires.  This can lead to link congestion and further packet loss.
   Thus, the attempt to prevent a packet from being dropped may instead
   affect many other packets.  Note that the "second" failure may simply
   be another manifestation of the same failure; see Figure 1.

   This memo proposes a mechanism for preventing further FRR once in
   cases where such further protection may be harmful.  Several examples
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