PCEP Extensions for Segment Routing
draft-ietf-pce-segment-routing-12

Document Type Active Internet-Draft (pce WG)
Last updated 2018-07-16 (latest revision 2018-06-29)
Replaces draft-sivabalan-pce-segment-routing
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PCE                                                         S. Sivabalan
Internet-Draft                                               C. Filsfils
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: December 31, 2018                                   J. Tantsura
                                                              Individual
                                                           W. Henderickx
                                                                   Nokia
                                                             J. Hardwick
                                                     Metaswitch Networks
                                                           June 29, 2018

                  PCEP Extensions for Segment Routing
                   draft-ietf-pce-segment-routing-12

Abstract

   Segment Routing (SR) enables any head-end node to select any path
   without relying on a hop-by-hop signaling technique (e.g., LDP or
   RSVP-TE).  It depends only on "segments" that are advertised by Link-
   State Interior Gateway Protocols (IGPs).  A Segment Routed Path can
   be derived from a variety of mechanisms, including an IGP Shortest
   Path Tree (SPT), explicit configuration, or a Path Computation
   Element (PCE).  This document specifies extensions to the Path
   Computation Element Protocol (PCEP) that allow a stateful PCE to
   compute and initiate Traffic Engineering (TE) paths, as well as a PCC
   to request a path subject to certain constraints and optimization
   criteria in SR networks.

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 BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

Sivabalan, et al.       Expires December 31, 2018               [Page 1]
Internet-Draft     PCEP Extensions for Segment Routing         June 2018

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 31, 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
   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
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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Overview of PCEP Operation in SR Networks . . . . . . . . . .   5
   4.  SR-Specific PCEP Message Extensions . . . . . . . . . . . . .   7
   5.  Object Formats  . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  The OPEN Object . . . . . . . . . . . . . . . . . . . . .   7
       5.1.1.  The SR PCE Capability sub-TLV . . . . . . . . . . . .   7
     5.2.  The RP/SRP Object . . . . . . . . . . . . . . . . . . . .   8
     5.3.  ERO . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
       5.3.1.  SR-ERO Subobject  . . . . . . . . . . . . . . . . . .   9
       5.3.2.  NAI Associated with SID . . . . . . . . . . . . . . .  11
     5.4.  RRO . . . . . . . . . . . . . . . . . . . . . . . . . . .  12
     5.5.  METRIC Object . . . . . . . . . . . . . . . . . . . . . .  13
   6.  Procedures  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.1.  Exchanging the SR PCE Capability  . . . . . . . . . . . .  13
     6.2.  ERO Processing  . . . . . . . . . . . . . . . . . . . . .  15
       6.2.1.  SR-ERO Validation . . . . . . . . . . . . . . . . . .  15
       6.2.2.  Interpreting the SR-ERO . . . . . . . . . . . . . . .  17
     6.3.  RRO Processing  . . . . . . . . . . . . . . . . . . . . .  20
   7.  Backward Compatibility  . . . . . . . . . . . . . . . . . . .  20
   8.  Management Considerations . . . . . . . . . . . . . . . . . .  21
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