IGP Extensions for Segment Routing Service Segment
draft-lz-lsr-igp-sr-service-segments-02

Document Type Active Internet-Draft (individual)
Authors Liu Yao  , Zheng Zhang 
Last updated 2020-07-10
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LSR Working Group                                               Yao. Liu
Internet-Draft                                              Zheng. Zhang
Intended status: Standards Track                         ZTE Corporation
Expires: January 11, 2021                                  July 10, 2020

           IGP Extensions for Segment Routing Service Segment
                draft-lz-lsr-igp-sr-service-segments-02

Abstract

   This document defines extensions to the link-state routing protocols
   (IS-IS and OSPF) in order to carry service segment information via
   IGP.

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   This Internet-Draft will expire on January 11, 2021.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IGP Extensions for Service Segments . . . . . . . . . . . . .   3
     2.1.  IS-IS Extensions  . . . . . . . . . . . . . . . . . . . .   3
     2.2.  OSPFv2 and OSPFv3 Extensions  . . . . . . . . . . . . . .   6
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Segments are introduced in the SR architecture [RFC8402].  Segment
   Routing (SR) allows for a flexible definition of end-to-end paths by
   encoding paths as sequences of topological sub-paths, called
   "segments".

   Service Function Chaining (SFC) [RFC7665] provides support for the
   creation of composite services that consist of an ordered set of
   Service Functions (SF) that are to be applied to packets and/or
   frames selected as a result of classification.

   [I-D.ietf-spring-sr-service-programming] describes how a service can
   be associated with a SID and how to achieve service funtion chaining
   in SR-enabled MPLS and IPv6 networks.  It also defines SR-aware and
   SR-unaware services.  For a SR-unaware service ,there has to be a SR
   proxy handling the SR processing on behalf of the service .

   [I-D.dawra-idr-bgp-ls-sr-service-segments] propose extensions to BGP-
   LS for Service Chaining to distribute the service segment information
   to SR Controller.

   The network topology is shown in figure 1.

                  SR-C
                    |
                    |
               A----1----2----3----4----5----B
                         |         |
                         |         |
                         S1        S2 proxy----S2

                      Figure 1: Network with Services

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   Node 1-5 are nodes capital of segment routing.  A and B are two end
   hosts.  S1 is an SR-aware Service.  S2 is an SR-unaware Service.

   SR Controller (SR-C) is connected to node 1, but may be attached to
   any node 1-5 in the network.

   SR-C is capable of receiving BGP-LS updates to discover topology, and
   calculating constrained paths between 1 and 5.

   Node 1 can use the BGP-LS extensions
   [I-D.ietf-spring-sr-service-programming] to advertise the service
   segment information to the SR-C, but it must get the information from
   other nodes at first.

   This document proposes extensions for IGP to advertise service
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