Segment Routing Architecture
draft-ietf-spring-segment-routing-12

Document Type Active Internet-Draft (spring WG)
Last updated 2017-06-20
Replaces draft-filsfils-spring-segment-routing
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication (wg milestones: Dec 2015 - Specification of a h..., Dec 2015 - One or more control ..., Apr 2016 - Requirements for mod... )
Document shepherd Martin Vigoureux
Shepherd write-up Show (last changed 2017-02-21)
IESG IESG state AD Evaluation
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Responsible AD Alvaro Retana
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Network Working Group                                   C. Filsfils, Ed.
Internet-Draft                                           S. Previdi, Ed.
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: December 22, 2017                                   B. Decraene
                                                            S. Litkowski
                                                                  Orange
                                                               R. Shakir
                                                            Google, Inc.
                                                           June 20, 2017

                      Segment Routing Architecture
                  draft-ietf-spring-segment-routing-12

Abstract

   Segment Routing (SR) leverages the source routing paradigm.  A node
   steers a packet through an ordered list of instructions, called
   segments.  A segment can represent any instruction, topological or
   service-based.  A segment can have a semantic local to an SR node or
   global within an SR domain.  SR allows to enforce a flow through any
   topological path and service chain while maintaining per-flow state
   only at the ingress nodes to the SR domain.

   Segment Routing can be directly applied to the MPLS architecture with
   no change on the forwarding plane.  A segment is encoded as an MPLS
   label.  An ordered list of segments is encoded as a stack of labels.
   The segment to process is on the top of the stack.  Upon completion
   of a segment, the related label is popped from the stack.

   Segment Routing can be applied to the IPv6 architecture, with a new
   type of routing header.  A segment is encoded as an IPv6 address.  An
   ordered list of segments is encoded as an ordered list of IPv6
   addresses in the routing header.  The active segment is indicated by
   the Destination Address of the packet.  The next active segment is
   indicated by a pointer in the new routing header.

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.

Filsfils, et al.        Expires December 22, 2017               [Page 1]
Internet-Draft               Segment Routing                   June 2017

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   This Internet-Draft will expire on December 22, 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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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Companion Documents . . . . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Link-State IGP Segments . . . . . . . . . . . . . . . . . . .   7
     3.1.  IGP-Prefix Segment, Prefix-SID  . . . . . . . . . . . . .   7
       3.1.1.  Prefix-SID Algorithm  . . . . . . . . . . . . . . . .   7
       3.1.2.  MPLS Dataplane  . . . . . . . . . . . . . . . . . . .   8
       3.1.3.  IPv6 Dataplane  . . . . . . . . . . . . . . . . . . .   9
     3.2.  IGP-Node Segment, Node-SID  . . . . . . . . . . . . . . .  10
     3.3.  IGP-Anycast Segment, Anycast SID  . . . . . . . . . . . .  10
     3.4.  IGP-Adjacency Segment, Adj-SID  . . . . . . . . . . . . .  13
       3.4.1.  Parallel Adjacencies  . . . . . . . . . . . . . . . .  14
       3.4.2.  LAN Adjacency Segments  . . . . . . . . . . . . . . .  15
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