SR-TE Path Midpoint Protection
draft-hu-spring-segment-routing-proxy-forwarding-11

Document Type Active Internet-Draft (individual)
Authors Zhibo Hu , Huaimo Chen  , Junda Yao  , Chris Bowers  , Yongqing Zhu 
Last updated 2020-08-02
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Network Working Group                                              Z. Hu
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                                 H. Chen
Expires: February 3, 2021                                      Futurewei
                                                                  J. Yao
                                                     Huawei Technologies
                                                               C. Bowers
                                                        Juniper Networks
                                                                  Y. Zhu
                                                           China Telecom
                                                          August 2, 2020

                     SR-TE Path Midpoint Protection
          draft-hu-spring-segment-routing-proxy-forwarding-11

Abstract

   Segment Routing Traffic Engineering (SR-TE) supports the creation of
   explicit paths using segment lists containing adjacency-SIDs, node-
   SIDs, anycast-SIDs, and binding-SIDs.  When the segment list defining
   an SR-TE path contains a node-SID, and the node fails, the network
   may no longer be able to properly forward traffic on that SR-TE path.
   [I-D.ietf-rtgwg-segment-routing-ti-lfa] describes a mechanism that
   allows local repair actions on the direct neighbors of the failed
   node to temporarily route traffic to the node immediately following
   the failed node on the SR-TE path segment list.  However, once the
   IGP shortest paths have converged, the local repair mechanism is no
   longer sufficient to continue forwarding traffic using the original
   segment list of the SR-TE path, since the non-neighbors of the failed
   node will no longer have a route to reach the failed node.  This
   document describes a mechanism that allows traffic to continue to be
   forwarded on an SR-TE path for an extended period of time after the
   failure of a node used in the path's segment list.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute

Hu, et al.              Expires February 3, 2021                [Page 1]
Internet-Draft          SR-TE Midpoint Protection            August 2020

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Extensions to IGP for Proxy Forwarding  . . . . . . . . . . .   4
     2.1.  Extensions to OSPF  . . . . . . . . . . . . . . . . . . .   4
       2.1.1.  Advertising Proxy Forwarding  . . . . . . . . . . . .   4
       2.1.2.  Advertising Binding Segment . . . . . . . . . . . . .   7
     2.2.  Extensions to IS-IS . . . . . . . . . . . . . . . . . . .  10
       2.2.1.  Advertising Proxy Forwarding  . . . . . . . . . . . .  10
       2.2.2.  Advertising Binding Segment . . . . . . . . . . . . .  12
   3.  Building Proxy Forwarding Table . . . . . . . . . . . . . . .  13
     3.1.  Advertising Proxy Forwarding  . . . . . . . . . . . . . .  15
     3.2.  Building Proxy Forwarding Table . . . . . . . . . . . . .  15
   4.  Node Protection for Segment List  . . . . . . . . . . . . . .  15
     4.1.  Next Segment is an Adjacency Segment  . . . . . . . . . .  16
     4.2.  Next Segment is a Node Segment  . . . . . . . . . . . . .  16
     4.3.  Next Segment is a Binding Segment . . . . . . . . . . . .  17
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
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