Signaling Maximum SID Depth using Border Gateway Protocol Link-State
draft-tantsura-idr-bgp-ls-segment-routing-msd-00

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Authors Jeff Tantsura  , Greg Mirsky  , Siva Sivabalan  , Uma Chunduri 
Last updated 2016-03-09
Replaced by RFC 8814, RFC 8814
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IDR Working Group                                            J. Tantsura
Internet-Draft                                                 G. Mirsky
Intended status: Standards Track                                Ericsson
Expires: September 10, 2016                                 S. Sivabalan
                                                                   Cisco
                                                             U. Chunduri
                                                                Ericsson
                                                           March 9, 2016

  Signaling Maximum SID Depth using Border Gateway Protocol Link-State
            draft-tantsura-idr-bgp-ls-segment-routing-msd-00

Abstract

   This document discusses use of BGP-LS to expose node and/or link on a
   node MSD "Maximum SID Depth" to a centralized controller (PCE/SDN).

Status of This Memo

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   This Internet-Draft will expire on September 10, 2016.

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   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions used in this document . . . . . . . . . . . .   2
       1.1.1.  Terminology . . . . . . . . . . . . . . . . . . . . .   2
       1.1.2.  Requirements Language . . . . . . . . . . . . . . . .   3
   2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   3
   3.  MSD supported by a node . . . . . . . . . . . . . . . . . . .   3
   4.  MSD supported on a link . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   When Segment Routing tunnels are computed by a centralized
   controller, it is crucial that the controller knows MSD "Maximum SID
   Depth" of the node or link SR tunnel exits over, so it doesn't
   download a path with SID (label stack) of a depth more than the node
   or link configured is capable of imposing.This document describes how
   to use BGP-LS to expose the MSD of the node or link configured to a
   centralized controller.

1.1.  Conventions used in this document

1.1.1.  Terminology

   BGP-LS: Distribution of Link-State and TE Information using Border
   Gateway Protocol

   MSD: Maximum SID Depth

   PCC: Path Computation Client

   PCE: Path Computation Element

   PCEP: Path Computation Element Protocol

   SID: Segment Identifier

   SR: Segment routing

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1.1.2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

2.  Problem Statement

   In existing technology only PCEP has extension to signal the MSD (SR
   PCE Capability TLV/ METRIC Object as defined in
   [I-D.ietf-pce-segment-routing],If PCEP is not supported by the node
   (head-end of the SR tunnel) controller has no way to learn the MSD of
   the node/link configured.
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