OSPFv3 Extensions for Segment Routing
RFC 8666

Document Type RFC - Proposed Standard (December 2019; No errata)
Last updated 2019-12-06
Replaces draft-psenak-ospf-segment-routing-ospfv3-extension
Stream IETF
Formats plain text html xml pdf htmlized bibtex
Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Acee Lindem
Shepherd write-up Show (last changed 2018-08-02)
IESG IESG state RFC 8666 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Alvaro Retana
Send notices to Acee Lindem <acee@cisco.com>, aretana.ietf@gmail.com
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack


Internet Engineering Task Force (IETF)                    P. Psenak, Ed.
Request for Comments: 8666                               S. Previdi, Ed.
Category: Standards Track                            Cisco Systems, Inc.
ISSN: 2070-1721                                            December 2019

                 OSPFv3 Extensions for Segment Routing

Abstract

   Segment Routing (SR) allows a flexible definition of end-to-end paths
   within IGP topologies by encoding paths as sequences of topological
   subpaths called "segments".  These segments are advertised by the
   link-state routing protocols (IS-IS and OSPF).

   This document describes the OSPFv3 extensions required for Segment
   Routing with the MPLS data plane.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8666.

Copyright Notice

   Copyright (c) 2019 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
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
   2.  Terminology
   3.  Segment Routing Identifiers
     3.1.  SID/Label Sub-TLV
   4.  Segment Routing Capabilities
   5.  OSPFv3 Extended Prefix Range TLV
   6.  Prefix-SID Sub-TLV
   7.  Adjacency Segment Identifier (Adj-SID)
     7.1.  Adj-SID Sub-TLV
     7.2.  LAN Adj-SID Sub-TLV
   8.  Elements of Procedure
     8.1.  Intra-area Segment Routing in OSPFv3
     8.2.  Inter-area Segment Routing in OSPFv3
     8.3.  Segment Routing for External Prefixes
     8.4.  Advertisement of Adj-SID
       8.4.1.  Advertisement of Adj-SID on Point-to-Point Links
       8.4.2.  Adjacency SID on Broadcast or NBMA Interfaces
   9.  IANA Considerations
     9.1.  "OSPFv3 Extended-LSA TLVs" Registry
     9.2.  "OSPFv3 Extended-LSA Sub-TLVs" Registry
   10. TLV/Sub-TLV Error Handling
   11. Security Considerations
   12. References
     12.1.  Normative References
     12.2.  Informative References
   Contributors
   Authors' Addresses

1.  Introduction

   Segment Routing (SR) allows a flexible definition of end-to-end paths
   within IGP topologies by encoding paths as sequences of topological
   subpaths called "segments".  These segments are advertised by the
   link-state routing protocols (IS-IS and OSPF).  Prefix segments
   represent an ECMP-aware shortest path to a prefix (or a node) as per
   the state of the IGP topology.  Adjacency segments represent a hop
   over a specific adjacency between two nodes in the IGP.  A prefix
   segment is typically a multi-hop path while an adjacency segment, in
   most cases, is a one-hop path.  SR's control plane can be applied to
   both IPv6 and MPLS data planes, and it does not require any
   additional signaling (other than IGP extensions).  The IPv6 data
   plane is out of the scope of this specification; the OSPFv3 extension
   for SR with the IPv6 data plane will be specified in a separate
   document.  When used in MPLS networks, SR paths do not require any
   LDP or RSVP-TE signaling.  However, SR can interoperate in the
   presence of Label Switched Paths (LSPs) established with RSVP or LDP.

   This document describes the OSPFv3 extensions required for Segment
   Routing with the MPLS data plane.

   Segment Routing architecture is described in [RFC8402].

   Segment Routing use cases are described in [RFC7855].

2.  Terminology

   This section lists some of the terminology used in this document:

   ABR:        Area Border Router

   Adj-SID:    Adjacency Segment Identifier

   AS:         Autonomous System

   ASBR:       Autonomous System Boundary Router

   DR:         Designated Router

   IS-IS:      Intermediate System to Intermediate System

   LDP:        Label Distribution Protocol

   LSP:        Label Switched Path

   MPLS:       Multiprotocol Label Switching

   OSPF:       Open Shortest Path First

   SPF:        Shortest Path First

   RSVP:       Resource Reservation Protocol

   SID:        Segment Identifier

   SR:         Segment Routing
Show full document text