SR Policies for Path Segment and Bidirectional Path in BGP-LS
draft-li-idr-bgp-ls-sr-policy-path-segment-01

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Interdomain Routing Working Group                                  C. Li
Internet-Draft                                                   M. Chen
Intended status: Standards Track                                 J. Dong
Expires: April 25, 2019                                            Z. Li
                                                     Huawei Technologies
                                                        October 22, 2018

     SR Policies for Path Segment and Bidirectional Path in BGP-LS
             draft-li-idr-bgp-ls-sr-policy-path-segment-01

Abstract

   This document specifies the way of collecting configuration and
   states of SR policies carrying Path Segment and bidirectional path
   information by using BPG-LS.  Such information can be used by
   external conponents for many use cases such as performance
   measurement, path re-optimization and end-to-end protection.

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.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on April 25, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   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
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Carrying SR Path Sub-TLVs in BGP-LS . . . . . . . . . . . . .   3
     3.1.  SR Path Segment Sub-TLV . . . . . . . . . . . . . . . . .   4
     3.2.  Sub-TLVs for Bidirectional Path . . . . . . . . . . . . .   5
       3.2.1.  SR Bidirectional Path Sub-TLV . . . . . . . . . . . .   5
       3.2.2.  SR Reverse Path Segment List Sub-TLV  . . . . . . . .   6
   4.  Operations  . . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Segment routing (SR) [RFC8402] is a source routing paradigm that
   allows the ingress node steers packets into a specific path according
   to the Segment Routing Policy
   [I-D.ietf-spring-segment-routing-policy].

   However, the SR Policies defined in
   [I-D.ietf-spring-segment-routing-policy] only supports unidirectional
   SR paths and there is no path ID in a Segment List to identify an SR
   path.  For identifying an SR path and supporting bidirectional path
   [I-D.cheng-spring-mpls-path-segment], new policies carrying Path
   Segment and bidirectional path information are defined in
   [I-D.li-idr-sr-policy-path-segment-distribution], as well as the
   extensions to BGP to distribute new SR policies.  The Path Segment
   can be a Path Segment in SR-MPLS [I-D.cheng-spring-mpls-path-segment]
   , or a Path Segment in SRv6 [I-D.li-spring-srv6-path-segment], or
   other IDs that can identify a path.

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   In many network scenarios, the configuration and state of each TE
   Policy is required by a controller which allows the network operator