Segment Routing over IPv6 (SRv6) Network Programming
RFC 8986

Document Type RFC - Proposed Standard (February 2021; No errata)
Authors Clarence Filsfils  , Pablo Camarillo  , John Leddy  , Daniel Voyer  , Satoru Matsushima  , Zhenbin Li 
Last updated 2021-02-22
Replaces draft-filsfils-spring-srv6-network-programming
Stream IETF
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Stream WG state Submitted to IESG for Publication
Document shepherd Joel Halpern
Shepherd write-up Show (last changed 2020-06-28)
IESG IESG state RFC 8986 (Proposed Standard)
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Consensus Boilerplate Yes
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Responsible AD Martin Vigoureux
Send notices to Bruno Decraene <>, Joel Halpern <>
IANA IANA review state Version Changed - Review Needed
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Internet Engineering Task Force (IETF)                  C. Filsfils, Ed.
Request for Comments: 8986                             P. Camarillo, Ed.
Category: Standards Track                            Cisco Systems, Inc.
ISSN: 2070-1721                                                 J. Leddy
                                                     Akamai Technologies
                                                                D. Voyer
                                                             Bell Canada
                                                           S. Matsushima
                                                                   Z. Li
                                                     Huawei Technologies
                                                           February 2021

          Segment Routing over IPv6 (SRv6) Network Programming


   The Segment Routing over IPv6 (SRv6) Network Programming framework
   enables a network operator or an application to specify a packet
   processing program by encoding a sequence of instructions in the IPv6
   packet header.

   Each instruction is implemented on one or several nodes in the
   network and identified by an SRv6 Segment Identifier in the packet.

   This document defines the SRv6 Network Programming concept and
   specifies the base set of SRv6 behaviors that enables the creation of
   interoperable overlays with underlay optimization.

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

Copyright Notice

   Copyright (c) 2021 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
   ( 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
     2.1.  Requirements Language
   3.  SRv6 SID
     3.1.  SID Format
     3.2.  SID Allocation within an SR Domain
     3.3.  SID Reachability
   4.  SR Endpoint Behaviors
     4.1.  End: Endpoint
       4.1.1.  Upper-Layer Header
     4.2.  End.X: L3 Cross-Connect
     4.3.  End.T: Specific IPv6 Table Lookup
     4.4.  End.DX6: Decapsulation and IPv6 Cross-Connect
     4.5.  End.DX4: Decapsulation and IPv4 Cross-Connect
     4.6.  End.DT6: Decapsulation and Specific IPv6 Table Lookup
     4.7.  End.DT4: Decapsulation and Specific IPv4 Table Lookup
     4.8.  End.DT46: Decapsulation and Specific IP Table Lookup
     4.9.  End.DX2: Decapsulation and L2 Cross-Connect
     4.10. End.DX2V: Decapsulation and VLAN L2 Table Lookup
     4.11. End.DT2U: Decapsulation and Unicast MAC L2 Table Lookup
     4.12. End.DT2M: Decapsulation and L2 Table Flooding
     4.13. End.B6.Encaps: Endpoint Bound to an SRv6 Policy with
     4.14. End.B6.Encaps.Red: End.B6.Encaps with Reduced SRH
     4.15. End.BM: Endpoint Bound to an SR-MPLS Policy
     4.16. Flavors
       4.16.1.  PSP: Penultimate Segment Pop of the SRH
       4.16.2.  USP: Ultimate Segment Pop of the SRH
       4.16.3.  USD: Ultimate Segment Decapsulation
   5.  SR Policy Headend Behaviors
     5.1.  H.Encaps: SR Headend with Encapsulation in an SR Policy
     5.2.  H.Encaps.Red: H.Encaps with Reduced Encapsulation
     5.3.  H.Encaps.L2: H.Encaps Applied to Received L2 Frames
     5.4.  H.Encaps.L2.Red: H.Encaps.Red Applied to Received L2 Frames
   6.  Counters
   7.  Flow-Based Hash Computation
   8.  Control Plane
     8.1.  IGP
     8.2.  BGP-LS
     8.3.  BGP IP/VPN/EVPN
     8.4.  Summary
   9.  Security Considerations
   10. IANA Considerations
     10.1.  Ethernet Next Header Type
     10.2.  SRv6 Endpoint Behaviors Registry
       10.2.1.  Registration Procedures
       10.2.2.  Initial Registrations
   11. References
     11.1.  Normative References
     11.2.  Informative References
   Authors' Addresses

1.  Introduction

   Segment Routing [RFC8402] leverages the source routing paradigm.  An
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