SRv6 Compressed Path Recover Method
draft-pl-spring-compr-path-recover-00

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SPRING Working Group                                            Yao. Liu
Internet-Draft                                              Shaofu. Peng
Intended status: Standards Track                         ZTE Corporation
Expires: December 30, 2020                                 June 28, 2020

                  SRv6 Compressed Path Recover Method
                 draft-pl-spring-compr-path-recover-00

Abstract

   This document describes a path information recovery method for
   compressed SRv6 segment lists.

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   This Internet-Draft will expire on December 30, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Segment List Recover TLV  . . . . . . . . . . . . . . . . . .   3
   4.  Illustration  . . . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Shifting Method . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  Stitching Method  . . . . . . . . . . . . . . . . . . . .   7
     4.3.  Mapping Method  . . . . . . . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Segment routing (SR) [RFC8402] is a source routing paradigm that
   explicitly indicates the forwarding path for packets at the ingress
   node by inserting an ordered list of instructions, called
   segments.Segment Routing can be deployed on the MPLS data plane by
   encoding 32-bits SIDs in MPLS label stack [RFC8660].  It can also be
   deployed on the IPv6 data plane by encoding a list of 128-bits SRv6
   SIDs in IPv6 Segment Routing Extension Header (SRH)[RFC8754].

   Several proposals are introduced to reduce the overhead for both the
   traffic volume and the network processor in SRv6.  The main ideas of
   them are basically to use a shorter ID associated with the complete
   128 bit SID.  The SRH does not carry complete path information after
   compression, however, the transit and egress nodes may need to know
   the complete SID information along the path in some scenarios such as
   OAM.

   This document describes a path information recovery method for
   compressed SRv6 segment lists.

2.  Overview

   Several proposals are introduced to reduce the overhead for both the
   traffic volume and the network processor in SRv6.  The main ideas of
   them are basically to use a shorter ID associated with the complete
   128 bit SID.  The method to establish such association could be
   mapping,stitching, shifting, or translation.

   Existing compression schemes use the 128 bit space as the carrier of
   compressing SIDs.  In the compressed SRH, the meaning of a 128 bit
   segment may be:

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   a) an uncompressed SID

   b) a unified prefix, followed by several short SIDs, and possibly
   existing end marker or padding, which is generally set to value 0

   c) short SIDs of the same type and length, possibly followed by end
   marker or padding, which is generally set to value 0