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Versions: 00 01 02 03 04 draft-ietf-pce-segment-routing-ipv6

PCE Working Group                                                M. Negi
Internet-Draft                                             P. Kaladharan
Intended status: Standards Track                                D. Dhody
Expires: April 21, 2018                              Huawei Technologies
                                                            S. Sivabalan
                                                           Cisco Systems
                                                        October 18, 2017


   PCEP Extensions for Segment Routing leveraging the IPv6 data plane
                 draft-negi-pce-segment-routing-ipv6-00

Abstract

   The Source Packet Routing in Networking (SPRING) architecture
   describes how Segment Routing (SR) can be used to steer packets
   through an IPv6 or MPLS network using the source routing paradigm.
   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).

   Since, Segment Routing can be applied to both MPLS and IPv6
   forwarding plane, a PCE should be able to compute SR-Path for both
   MPLS and IPv6 forwarding plane.  This draft describes the extensions
   required for Segment Routing support for IPv6 data plane in PCEP.

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




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   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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 April 21, 2018.

Copyright Notice

   Copyright (c) 2017 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
   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Overview of PCEP Operation in SRv6 Networks . . . . . . . . .   5
     3.1.  Operation Overview  . . . . . . . . . . . . . . . . . . .   6
     3.2.  SRv6-Specific PCEP Message Extensions . . . . . . . . . .   6
     3.3.  Object Formats  . . . . . . . . . . . . . . . . . . . . .   6
       3.3.1.  The OPEN Object . . . . . . . . . . . . . . . . . . .   6
         3.3.1.1.  The SRv6 PCE Capability TLV . . . . . . . . . . .   6
         3.3.1.2.  Exchanging SRv6 Capability  . . . . . . . . . . .   7
       3.3.2.  The RP/SRP Object . . . . . . . . . . . . . . . . . .   7
       3.3.3.  ERO Object  . . . . . . . . . . . . . . . . . . . . .   8
         3.3.3.1.  SR-ERO Subobject  . . . . . . . . . . . . . . . .   8
         3.3.3.2.  ERO Processing  . . . . . . . . . . . . . . . . .  10
       3.3.4.  RRO Object  . . . . . . . . . . . . . . . . . . . . .  11
         3.3.4.1.  SR-RRO Subobject  . . . . . . . . . . . . . . . .  11
     3.4.  Security Considerations . . . . . . . . . . . . . . . . .  11
     3.5.  IANA Considerations . . . . . . . . . . . . . . . . . . .  12
       3.5.1.  PCEP Objects  . . . . . . . . . . . . . . . . . . . .  12
         3.5.1.1.  ERROR Objects . . . . . . . . . . . . . . . . . .  12
         3.5.1.2.  TLV Type Indicators . . . . . . . . . . . . . . .  12
         3.5.1.3.  New Path Setup Type . . . . . . . . . . . . . . .  12



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   4.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     4.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     4.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Appendix A.  Contributor  . . . . . . . . . . . . . . . . . . . .  16
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   As per [I-D.ietf-spring-segment-routing], with Segment Routing (SR),
   a node steers a packet through an ordered list of instructions,
   called segments.  A segment can represent any instruction,
   topological or service-based.  A segment can have a semantic local to
   an SR node or global within an SR domain.  SR allows to enforce a
   flow through any path and service chain while maintaining per-flow
   state only at the ingress node of the SR domain.  Segments can be
   derived from different components: IGP, BGP, Services, Contexts,
   Locators, etc.  The list of segment forming the path is called the
   Segment List and is encoded in the packet header.  Segment Routing
   can be applied to the IPv6 architecture with the Segment Routing
   Header (SRH) [I-D.ietf-6man-segment-routing-header].  A segment is
   encoded as an IPv6 address.  An ordered list of segments is encoded
   as an ordered list of IPv6 addresses in the routing header.  The
   active segment is indicated by the Destination Address of the packet.
   Upon completion of a segment, a pointer in the new routing header is
   incremented and indicates the next segment.

   Segment Routing use cases are described in [RFC7855] and
   [I-D.ietf-spring-ipv6-use-cases].  Segment Routing protocol
   extensions are defined in [I-D.ietf-isis-segment-routing-extensions],
   and [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

   As per [I-D.ietf-6man-segment-routing-header], an SRv6 Segment is a
   128-bit value.  "SRv6 SID" or simply "SID" are often used as a
   shorter reference for "SRv6 Segment".  Further details are in An
   illustration is provided in
   [I-D.filsfils-spring-srv6-network-programming].

   The SR architecture can be applied to the MPLS forwarding plane
   without any change, in which case an SR path corresponds to an MPLS
   Label Switching Path (LSP).  The SR is applied to IPV6 forwarding
   plane using SRH.  A SR path can be derived from an IGP Shortest Path
   Tree (SPT), but SR-TE paths may not follow IGP SPT.  Such paths may
   be chosen by a suitable network planning tool or an and provisioned
   on the ingress node.

   [RFC5440] describes Path Computation Element Protocol (PCEP) for
   communication between a Path Computation Client (PCC) and a Path
   Computation Element (PCE) or between one a pair of PCEs.  A PCE or a



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   PCC operating as a PCE (in hierarchical PCE environment) computes
   paths for MPLS Traffic Engineering LSPs (MPLS-TE LSPs) based on
   various constraints and optimization criteria.  [RFC8231] specifies
   extensions to PCEP that allow a stateful PCE to compute and recommend
   network paths in compliance with [RFC4657] and defines objects and
   TLVs for MPLS-TE LSPs.  Stateful PCEP extensions provide
   synchronization of LSP state between a PCC and a PCE or between a
   pair of PCEs, delegation of LSP control, reporting of LSP state from
   a PCC to a PCE, controlling the setup and path routing of an LSP from
   a PCE to a PCC.  Stateful PCEP extensions are intended for an
   operational model in which LSPs are configured on the PCC, and
   control over them is delegated to the PCE.

   A mechanism to dynamically initiate LSPs on a PCC based on the
   requests from a stateful PCE or a controller using stateful PCE is
   specified in [I-D.ietf-pce-pce-initiated-lsp].  As per
   [I-D.ietf-pce-segment-routing], it is possible to use a stateful PCE
   for computing one or more SR-TE paths taking into account various
   constraints and objective functions.  Once a path is chosen, the
   stateful PCE can initiate an SR-TE path on a PCC using PCEP
   extensions specified in [I-D.ietf-pce-pce-initiated-lsp] using the SR
   specific PCEP extensions specified in [I-D.ietf-pce-segment-routing].
   [I-D.ietf-pce-segment-routing] specifies PCEP extensions for
   supporting a SR-TE LSP for MPLS data plane.  This document extends
   [I-D.ietf-pce-segment-routing] to support SR for IPv6 data plane.
   Additionally, using procedures described in this document, a PCC can
   request an SRv6 path from either stateful or a stateless PCE.  This
   specification relies on the PATH-SETUP-TYPE TLV and procedures
   specified in [I-D.ietf-pce-lsp-setup-type].

2.  Terminology

   This document uses the following terms defined in [RFC5440]: PCC,
   PCE, PCEP Peer.

   This document uses the following terms defined in [RFC8051]: Stateful
   PCE, Delegation.

   The message formats in this document are specified using Routing
   Backus-Naur Format (RBNF) encoding as specified in [RFC5511].

   PCC:  Path Computation Client.

   PCE:  Path Computation Element.

   PCEP:  Path Computation Element Protocol.

   SR:  Segment Routing.



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   SID:  Segment Identifier.

   SRv6:  Segment Routing for IPv6 forwarding plane.

   SRH:  IPv6 Segment Routing Header.

   SR Path:  IPv6 Segment (List of IPv6 SID representing a path in IPv6
      SR domain)

3.  Overview of PCEP Operation in SRv6 Networks

   Basic operations for PCEP speakers is as per
   [I-D.ietf-pce-segment-routing].  SRv6 Paths computed by a PCE can be
   represented as an ordered list of SRv6 segments of 128-bit value.
   "SRv6 SID" or simply "SID" are often used as a shorter reference for
   "SRv6 Segment".

   [I-D.ietf-pce-segment-routing] defined a new ERO subobject denoted by
   "SR-ERO subobject" capable of carrying a SID as well as the identity
   of the node/adjacency represented by the SID.  SR-capable PCEP
   speakers should be able to generate and/or process such ERO
   subobject.  An ERO containing SR-ERO subobjects can be included in
   the PCEP Path Computation Reply (PCRep) message defined in [RFC5440],
   the PCEP LSP Initiate Request message (PCInitiate) defined in
   [I-D.ietf-pce-pce-initiated-lsp], as well as in the PCEP LSP Update
   Request (PCUpd) and PCEP LSP State Report (PCRpt) messages defined in
   defined in [RFC8231].

   This document extends the "SR-ERO subobject" defined in
   [I-D.ietf-pce-segment-routing] to carry IPv6 SID(s) (IPv6 Addresses).
   SRv6-capable PCEP speakers should be able to generate and/or process
   this.

   When a PCEP session between a PCC and a PCE is established, both PCEP
   speakers exchange their capabilities to indicate their ability to
   support SRv6 specific functionality.

   In summary, this document defines new path setup type carried in the
   PATH-SETUP-TYPE TLV for SRv6 path.

   In summary, this document:

   o  Defines a new PCEP capability for SRv6

   o  Update the SR-ERO and SR-RRO sub-object for SRv6

   o  Defines a new path setup type carried in the PATH-SETUP-TYPE TLV
      for SR-TE LSP.



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3.1.  Operation Overview

   In SR networks, an ingress node of an SR path appends all outgoing
   packets with an SR header consisting of a list of SIDs (IPv6 Prefix
   in case of SRv6).  The header has all necessary information to guide
   the packets from the ingress node to the egress node of the path, and
   hence there is no need for any signaling protocol.

   For IPv6 in control plane with MPLS data-plane, mechanism remains
   same as [I-D.ietf-pce-segment-routing]

   This document describes extensions to SR path for IPv6 data plane.
   SRv6 Path (i.e.  ERO) consists of an ordered set of SIDs(see details
   in Figure 2).

   A PCC or PCE indicates its ability to support SRv6 during the PCEP
   session Initialization Phase via a new SRv6-PCE-CAPABILITY TLV (see
   details in Section 3.3.1.1).

3.2.  SRv6-Specific PCEP Message Extensions

   As defined in [RFC5440], a PCEP message consists of a common header
   followed by a variable length body made up of mandatory and/or
   optional objects.  This document does not require any changes in the
   format of PCReq and PCRep messages specified in [RFC5440], PCInitiate
   message specified in [I-D.ietf-pce-pce-initiated-lsp], and PCRpt and
   PCUpd messages specified in [RFC8231].  However, PCEP messages
   pertaining to SRv6 MUST include PATH-SETUP-TYPE TLV in the RP or SRP
   object to clearly identify that SRv6 is intended.  In other words, a
   PCEP speaker MUST NOT infer whether or not a PCEP message pertains to
   SRv6 from any other object or TLV.

3.3.  Object Formats

3.3.1.  The OPEN Object

   This document defines a new optional TLV for use in the OPEN Object.

3.3.1.1.  The SRv6 PCE Capability TLV

   The SRv6-PCE-CAPABILITY TLV is an optional TLV associated with the
   OPEN Object to exchange SRv6 capability of PCEP speakers.  The format
   of the SR-PCE-CAPABILITY TLV is shown in the following figure:








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        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            Type=TBD1          |            Length=4           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      max-SL   |  Reserved     |             Flags           |L|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                 Figure 1: SRv6-PCE-CAPABILITY TLV format

   The code point for the TLV type is to be defined by IANA.  The TLV
   length is 4 octets.

   The 4-octet value comprise of -

      max-SL: 1 octet, this field specifies the maximum value of the
      "Segments Left (SL)" in the SRH
      [I-D.ietf-6man-segment-routing-header].

      Reserved: 1 octet, this field MUST be set to 0 on transmission,
      and ignored on receipt.

      Flags: 2 octet, one flag is currently defined in this document.

         L bit: A PCC sets this bit to 1 to indicate that it does not
         impose any limit on SL.

3.3.1.2.  Exchanging SRv6 Capability

   By including the SRv6-PCE-CAPABILITY TLV in the OPEN message destined
   to a PCE, a PCC indicates that it is capable of supporting the head-
   end functions for SRv6.  By including the TLV in the OPEN message
   destined to a PCC, a PCE indicates that it is capable of computing
   SRv6 paths.

3.3.2.  The RP/SRP Object

   In order to indicate the SRv6 path, RP or SRP object MUST include the
   PATH-SETUP-TYPE TLV specified in [I-D.ietf-pce-lsp-setup-type].  This
   document defines a new Path Setup Type (PST) for SRv6 as follows:

   o PST = TBD2: Path is setup using SRv6 technique.








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3.3.3.  ERO Object

   In order to support SRv6, the SR-ERO subobject is used
   [I-D.ietf-pce-segment-routing].  All other processing rules remains
   the same.

3.3.3.1.  SR-ERO Subobject

   For supporting SRv6, a new SID Type (ST) is defined, the format of
   SR-ERO sub object remains the same as defined in
   [I-D.ietf-pce-segment-routing].

   When the SID Type (ST) indicates SRv6, then the SR-ERO subobject
   represent a SRv6 segment and include a field SRv6I (SRv6 Identifier)
   in place of NAI (Node or Adjacency Identifier) defined in
   [I-D.ietf-pce-segment-routing].  The 32 bit SID MUST be set to zero
   on transit and ignored on receipt.  The format of SR-ERO subobject is
   reproduced with the SRv6I field as shown below:


        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |L|    Type     |     Length    |  ST   |     Flags     |F|S|C|M|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                              SID                              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       //                     SRv6I (variable)                        //
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                     Figure 2: SR-ERO Subobject Format

   The description of all the flags and fields is as per
   [I-D.ietf-pce-segment-routing].

   For SRv6 segments, a new ST (SID Type) is assigned by IANA as TBD.

   For SRv6 segments (when ST is TBD), M and C flag MUST NOT be set.
   The S flag MUST be set and SID field MUST be set to 0.  The F bit
   MUST NOT be set.  The Length is 28.

   The SRv6I format is as shown below:








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         0                   1                   2                   3
         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                      SRv6 Identifier                          |
      |                         (128-bit)                             |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | SRv6ST|         Flags           |       Function Code         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      //                        NAI (variable)                       //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                 Figure 3: SR-ERO Subobject's SRv6I Format

      SRv6 Identifier is the 128 bit IPv6 addresses representing SRv6
      segment.

      SRv6ST is the SRv6 SID Type which indicates the interpretation for
      NAI (Node or Adjacency Identifier) as per
      [I-D.ietf-pce-segment-routing].

      Flags is the 12 bit field, no flag bits are currently defined in
      this document.

      Function Code is is the 16 bit field representing supported
      functions.  associated with SRv6 SIDs.  See
      [I-D.filsfils-spring-srv6-network-programming].  Following
      function codes are currently defined -

         0: Reserved

         1: End Function

         2: End.DX6 Function

         3: End.DT6 Function

         4: End.X Function

      NAI field [I-D.ietf-pce-segment-routing] contains the NAI
      associated with the SRv6 Identifier.  Depending on the value of
      SRv6ST, the NAI can have different formats.

         When SRv6ST value is 1, the NAI is as per the 'IPv6 Node ID'
         format defined in [I-D.ietf-pce-segment-routing], which specify




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         an IPv6 address.  This is used to identify the owner of the
         SRv6 Identifier.

         When SRv6ST value is 2, the NAI is as per the 'IPv6 Adjacency'
         format defined in [I-D.ietf-pce-segment-routing], which specify
         a pair of IPv6 addresses.  This is used to identify the IPv6
         Adjacency and used with the SRv6 Adj-SID.

         Note that when SRv6ST value is 0, NAI is not included and MUST
         be NULL.

3.3.3.2.  ERO Processing

   The ERO and SR-ERO subobject processing remains as per [RFC5440] and
   [I-D.ietf-pce-segment-routing].

   The ST MUST only be TDB, if the SRv6-PCE-CAPABILITY TLV is exchanged
   with the PCEP peer.  In case a PCEP speaker receives the SR-ERO
   subobject with ST indicating SRv6 segment, when the SRv6-PCE-
   CAPABILITY TLV was not exchanged, it MUST send a PCErr message with
   Error-Type = 19 ("Invalid Operation") and Error-Value = TBD3
   ("Attempted SRv6 when the capability was not advertised").  A PCEP
   speaker that does not recognize the ST value, it would behave as per
   [I-D.ietf-pce-segment-routing].

   [Editor's Note - this is missing from
   [I-D.ietf-pce-segment-routing].]

   If a PCC receives a list of SRv6 segments, and the number of SRv6
   segments exceeds the max-SL that the PCC can impose on the packet
   (SRH), it MAY send a PCErr message with Error-Type = 10 ("Reception
   of an invalid object") and Error-Value = TBD ("Unsupported number of
   Segment ERO subobjects") as per [I-D.ietf-pce-segment-routing].

   When a PCEP speaker detects that all subobjects of ERO are not
   identical to SRv6, and if it does not handle such ERO, it MUST send a
   PCErr message with Error-Type = 10 ("Reception of an invalid object")
   and Error-Value = TBD ("Non-identical ERO subobjects")as per
   [I-D.ietf-pce-segment-routing].

   When a PCEP speaker receives an SR-ERO subobject for SRv6 segment, M,
   C and F flag MUST NOT be set and S flag MUST be set.  Otherwise, it
   MUST consider the entire ERO object invalid and send a PCErr message
   with Error-Type = 10 ("Reception of an invalid object") and Error-
   Value = TBD ("Malformed object") as per
   [I-D.ietf-pce-segment-routing].  The PCEP speaker MAY include the
   malformed SR-ERO object in the PCErr message as well.




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3.3.4.  RRO Object

   In order to support SRv6, the SR-ERO Subobject is used
   [I-D.ietf-pce-segment-routing].  All other processing rules remains
   the same.

3.3.4.1.  SR-RRO Subobject

   For SRv6 segments, a new ST (SID Type) is assigned by IANA as TBD,
   the format of SR-ERO sub object remains the same as defined in
   [I-D.ietf-pce-segment-routing].

   When the SID Type (ST) indicates SRv6, then the SR-RRO subobject
   represent a SRv6 segment and include a field SRv6I (SRv6 Identifier)
   in place of NAI (Node or Adjacency Identifier) defined in
   [I-D.ietf-pce-segment-routing].  The 32 bit SID MUST be set to zero
   on transit and ignored on receipt.  The format of SR-RRO subobject is
   reproduced with the SRv6I field as shown below:


        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      Type     |     Length    |  ST   |     Flags     |F|S|C|M|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                              SID                              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       //                     SRv6I (variable)                        //
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                     Figure 4: SR-RRO Subobject Format

   The description of all fields and flags is as per SR-ERO subobject.

   Processing rules of SR-RRO subobject are identical to those of SR-ERO
   subobject.

3.4.  Security Considerations

   The security considerations described in [RFC5440], [RFC8231] and
   [I-D.ietf-pce-pce-initiated-lsp] are applicable to this
   specification.  No additional security measure is required.








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3.5.  IANA Considerations

   This document requests IANA to include (I) bit in flags registry for
   SR-ERO and SR-RRO sub-objects.  Other changes are defined as:

3.5.1.  PCEP Objects

3.5.1.1.  ERROR Objects

   IANA is requested to allocate code-points in the PCEP-ERROR Object
   Error Types and Values registry for the following new error-values:


      Error-Type   Meaning
      ----------   -------
      19           Invalid Operation
                   Error-value = TBD3 (Attempted SRv6 when the
                   capability was not advertised)


3.5.1.2.  TLV Type Indicators

   IANA is requested to make the assignment of the new code points for
   the existing "PCEP TLV Type Indicators" registry as follows:

      Value     Meaning                     Reference
      -----     -------                     ---------
      TBD1      SRv6-PCE-CAPABILITY TLV     This Document

3.5.1.3.  New Path Setup Type

   [I-D.ietf-pce-lsp-setup-type]defines the PATH-SETUP-TYPE TLV and
   requests that IANA creates a registry to manage the value of the
   PATH-SETUP-TYPE TLV's PST field.  IANA is requested to allocate a new
   code point in the PCEP PATH_SETUP_TYPE TLV PST field registry, as
   follows:


   Value                     Description                  Reference
   ------------------------- ---------------------------- --------------
   TBD2                      SRv6 (SRH) technique         This Document










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4.  References

4.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC5511]  Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
              Used to Form Encoding Rules in Various Routing Protocol
              Specifications", RFC 5511, DOI 10.17487/RFC5511, April
              2009, <https://www.rfc-editor.org/info/rfc5511>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

   [I-D.ietf-pce-segment-routing]
              Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "PCEP Extensions for Segment Routing",
              draft-ietf-pce-segment-routing-10 (work in progress),
              October 2017.

   [I-D.ietf-spring-segment-routing]
              Filsfils, C., Previdi, S., Decraene, B., Litkowski, S.,
              and R. Shakir, "Segment Routing Architecture", draft-ietf-
              spring-segment-routing-12 (work in progress), June 2017.

   [I-D.ietf-pce-pce-initiated-lsp]
              Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP
              Extensions for PCE-initiated LSP Setup in a Stateful PCE
              Model", draft-ietf-pce-pce-initiated-lsp-11 (work in
              progress), October 2017.






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   [I-D.ietf-pce-lsp-setup-type]
              Sivabalan, S., Tantsura, J., Minei, I., Varga, R., and J.
              Hardwick, "Conveying path setup type in PCEP messages",
              draft-ietf-pce-lsp-setup-type-04 (work in progress), April
              2017.

4.2.  Informative References

   [RFC4657]  Ash, J., Ed. and J. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol Generic
              Requirements", RFC 4657, DOI 10.17487/RFC4657, September
              2006, <https://www.rfc-editor.org/info/rfc4657>.

   [RFC7855]  Previdi, S., Ed., Filsfils, C., Ed., Decraene, B.,
              Litkowski, S., Horneffer, M., and R. Shakir, "Source
              Packet Routing in Networking (SPRING) Problem Statement
              and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
              2016, <https://www.rfc-editor.org/info/rfc7855>.

   [RFC8051]  Zhang, X., Ed. and I. Minei, Ed., "Applicability of a
              Stateful Path Computation Element (PCE)", RFC 8051,
              DOI 10.17487/RFC8051, January 2017,
              <https://www.rfc-editor.org/info/rfc8051>.

   [I-D.ietf-6man-segment-routing-header]
              Previdi, S., Filsfils, C., Raza, K., Leddy, J., Field, B.,
              daniel.voyer@bell.ca, d., daniel.bernier@bell.ca, d.,
              Matsushima, S., Leung, I., Linkova, J., Aries, E., Kosugi,
              T., Vyncke, E., Lebrun, D., Steinberg, D., and R. Raszuk,
              "IPv6 Segment Routing Header (SRH)", draft-ietf-6man-
              segment-routing-header-07 (work in progress), July 2017.

   [I-D.ietf-spring-ipv6-use-cases]
              Brzozowski, J., Leddy, J., Filsfils, C., Maglione, R., and
              M. Townsley, "IPv6 SPRING Use Cases", draft-ietf-spring-
              ipv6-use-cases-11 (work in progress), June 2017.

   [I-D.ietf-isis-segment-routing-extensions]
              Previdi, S., Filsfils, C., Bashandy, A., Gredler, H.,
              Litkowski, S., Decraene, B., and j. jefftant@gmail.com,
              "IS-IS Extensions for Segment Routing", draft-ietf-isis-
              segment-routing-extensions-13 (work in progress), June
              2017.








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   [I-D.ietf-ospf-ospfv3-segment-routing-extensions]
              Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
              Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3
              Extensions for Segment Routing", draft-ietf-ospf-ospfv3-
              segment-routing-extensions-10 (work in progress),
              September 2017.

   [I-D.filsfils-spring-srv6-network-programming]
              Filsfils, C., Leddy, J., daniel.voyer@bell.ca, d.,
              daniel.bernier@bell.ca, d., Steinberg, D., Raszuk, R.,
              Matsushima, S., Lebrun, D., Decraene, B., Peirens, B.,
              Salsano, S., Naik, G., Elmalky, H., Jonnalagadda, P.,
              Sharif, M., Ayyangar, A., Mynam, S., Henderickx, W.,
              Bashandy, A., Raza, K., Dukes, D., Clad, F., and P.
              Camarillo, "SRv6 Network Programming", draft-filsfils-
              spring-srv6-network-programming-01 (work in progress),
              June 2017.


































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Appendix A.  Contributor

   The following persons contributed to this document:

   Huang Wumin
   Huawei Technologies
   Huawei Building, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: huangwumin@huawei.com

Authors' Addresses

   Mahendra Singh Negi
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka  560066
   India

   EMail: mahendrasingh@huawei.com


   Prejeeth Kaladharan
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka  560066
   India

   EMail: prejeeth.k@huawei.com


   Dhruv Dhody
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka  560066
   India

   EMail: dhruv.ietf@gmail.com


   Siva Sivabalan
   Cisco Systems

   EMail: msiva@cisco.com






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