A Unified Approach to IP Segment Routing
draft-bryant-mpls-unified-ip-sr-00

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Last updated 2017-06-28
Replaced by draft-xu-mpls-sr-over-ip
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MPLS Working Group                                             S. Bryant
Internet-Draft                                                     X. Xu
Intended status: Standards Track                                 M. Chen
Expires: December 30, 2017                                        Huawei
                                                               A. Farrel
                                                                J. Drake
                                                        Juniper Networks
                                                           June 28, 2017

                A Unified Approach to IP Segment Routing
                   draft-bryant-mpls-unified-ip-sr-00

Abstract

   Segment routing is a new and powerful forwarding paradigm that allows
   packets to be steered through a network on paths other than the
   shortest path derived from the routing protocol.  The approach uses
   information encoded in the packet header and does not make use of a
   signaling protocol to pre-install paths in the network.

   Two different encapsulations have been defined to enable segment
   routing in an MPLS network and in an IPv6 network.  While
   acknowledging that there is a strong need to support segment routing
   in both environments, this document defines a converged, unified
   approach to segment routing that enables a single mechanism to be
   applied in both types of network.  The resulting approach is also
   applicable to IPv4 networks without the need for any changes to the
   IPv4 specification.

   This document makes no changes to the segment routing architecture
   and builds on existing protocol mechanisms such as the encapsulation
   of MPLS within UDP defined in RFC 7510.

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
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Bryant, et al.          Expires December 30, 2017               [Page 1]
Internet-Draft                Unified IP SR                    June 2017

   This Internet-Draft will expire on December 30, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  The Unified Segment Routing Protocol Stack  . . . . . . . . .   3
   4.  The Segment Routing Instruction Stack . . . . . . . . . . . .   5
     4.1.  SRIS Format . . . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  TTL . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  UDP/IP Encapsulation. . . . . . . . . . . . . . . . . . . . .   6
   6.  Metadata  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   7.  Elements of Procedure . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Domain Ingress  . . . . . . . . . . . . . . . . . . . . .   7
     7.2.  Legacy Transit  . . . . . . . . . . . . . . . . . . . . .   8
     7.3.  On-Path Pass-Through SR Nodes . . . . . . . . . . . . . .   8
     7.4.  SR Transit Nodes  . . . . . . . . . . . . . . . . . . . .   8
     7.5.  Penultimate SR Transit  . . . . . . . . . . . . . . . . .   9
     7.6.  Domain Egress . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Modes of Deployment . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Interconnection of SR Domains . . . . . . . . . . . . . .   9
     8.2.  SR Within and IP Network  . . . . . . . . . . . . . . . .  10
   9.  OAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   10. Comparison with SRv6  . . . . . . . . . . . . . . . . . . . .  11
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  12
   12. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
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