Segment Routing Policy Architecture
draft-ietf-spring-segment-routing-policy-02

Document Type Active Internet-Draft (spring WG)
Last updated 2018-10-22
Replaces draft-filsfils-spring-segment-routing-policy
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SPRING Working Group                                         C. Filsfils
Internet-Draft                                         S. Sivabalan, Ed.
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: April 25, 2019                                         D. Voyer
                                                             Bell Canada
                                                             A. Bogdanov
                                                            Google, Inc.
                                                               P. Mattes
                                                               Microsoft
                                                        October 22, 2018

                  Segment Routing Policy Architecture
            draft-ietf-spring-segment-routing-policy-02.txt

Abstract

   Segment Routing (SR) allows a headend node to steer a packet flow
   along any path.  Intermediate per-flow states are eliminated thanks
   to source routing.  The headend node steers a flow into an SR Policy.
   The header of a packet steered in an SR Policy is augmented with an
   ordered list of segments associated with that SR Policy.  This
   document details the concepts of SR Policy and steering into an SR
   Policy.

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 [RFC2119].

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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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 25, 2019.

Filsfils, et al.         Expires April 25, 2019                 [Page 1]
Internet-Draft                  SR Policy                   October 2018

Copyright Notice

   Copyright (c) 2018 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.  SR Policy . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Identification of an SR Policy  . . . . . . . . . . . . .   4
     2.2.  Candidate Path and Segment List . . . . . . . . . . . . .   4
     2.3.  Protocol-Origin of a Candidate Path . . . . . . . . . . .   5
     2.4.  Originator of a Candidate Path  . . . . . . . . . . . . .   5
     2.5.  Discriminator of a Candidate Path . . . . . . . . . . . .   6
     2.6.  Identification of a Candidate Path  . . . . . . . . . . .   7
     2.7.  Preference of a Candidate Path  . . . . . . . . . . . . .   7
     2.8.  Validity of a Candidate Path  . . . . . . . . . . . . . .   7
     2.9.  Active Candidate Path . . . . . . . . . . . . . . . . . .   7
     2.10. Validity of an SR Policy  . . . . . . . . . . . . . . . .   9
     2.11. Instantiation of an SR Policy in the Forwarding Plane . .   9
     2.12. Priority of an SR Policy  . . . . . . . . . . . . . . . .   9
     2.13. Summary . . . . . . . . . . . . . . . . . . . . . . . . .   9
   3.  Segment Routing Database  . . . . . . . . . . . . . . . . . .  10
   4.  Segment Types . . . . . . . . . . . . . . . . . . . . . . . .  11
     4.1.  Explicit Null . . . . . . . . . . . . . . . . . . . . . .  14
   5.  Validity of a Candidate Path  . . . . . . . . . . . . . . . .  15
     5.1.  Explicit Candidate Path . . . . . . . . . . . . . . . . .  15
     5.2.  Dynamic Candidate Path  . . . . . . . . . . . . . . . . .  16
   6.  Binding SID . . . . . . . . . . . . . . . . . . . . . . . . .  17
     6.1.  BSID of a candidate path  . . . . . . . . . . . . . . . .  17
     6.2.  BSID of an SR Policy  . . . . . . . . . . . . . . . . . .  17
     6.3.  Forwarding Plane  . . . . . . . . . . . . . . . . . . . .  18
     6.4.  Non-SR usage of Binding SID . . . . . . . . . . . . . . .  19
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