RSVP-TE Extensions for Associated Bidirectional LSPs
draft-ietf-ccamp-mpls-tp-rsvpte-ext-associated-lsp-08

The information below is for an old version of the document
Document Type Active Internet-Draft (ccamp WG)
Authors Fei Zhang  , Ruiquan Jing  , Rakesh Gandhi 
Last updated 2014-03-02
Replaces draft-zhang-mpls-tp-rsvpte-ext-associated-lsp
Replaced by RFC 7551, RFC 7551
Stream Internet Engineering Task Force (IETF)
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CCAMP Working Group                                        F. Zhang, Ed.
Internet-Draft                                                       ZTE
Intended status: Standards Track                                 R. Jing
Expires: September 3, 2014                                 China Telecom
                                                          R. Gandhi, Ed.
                                                           Cisco Systems
                                                           March 2, 2014

          RSVP-TE Extensions for Associated Bidirectional LSPs
         draft-ietf-ccamp-mpls-tp-rsvpte-ext-associated-lsp-08

Abstract

   This document describes Resource reSerVation Protocol (RSVP)
   extensions to bind two point-to-point unidirectional Label Switched
   Paths (LSPs) into an associated bidirectional LSP. The association is
   achieved by defining the new Association Types in (Extended)
   ASSOCIATION object. In addition, RSVP extensions allow asymmetric
   upstream and downstream bandwidths for the bidirectional LSP.

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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   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."

Copyright Notice

   Copyright (c) 2014 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
   (http://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
 

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions used in this document  . . . . . . . . . . . . . .  4
   3.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Provisioning Model Overview  . . . . . . . . . . . . . . .  4
       3.1.1.  Single Sided Provisioning  . . . . . . . . . . . . . .  4
       3.1.2.  Double Sided Provisioning  . . . . . . . . . . . . . .  4
     3.2.  Association Signaling Overview . . . . . . . . . . . . . .  5
       3.2.1.  Single Sided Provisioning  . . . . . . . . . . . . . .  5
       3.2.2.  Double Sided Provisioning  . . . . . . . . . . . . . .  6
     3.3.  Asymmetric Bandwidth Signaling Overview  . . . . . . . . .  6
       3.3.1.  Single Sided Provisioning  . . . . . . . . . . . . . .  6
       3.3.2.  Double Sided Provisioning  . . . . . . . . . . . . . .  6
     3.4.  Recovery LSP Overview  . . . . . . . . . . . . . . . . . .  7
       3.4.1.  Single Sided Provisioning  . . . . . . . . . . . . . .  7
       3.4.2.  Double Sided Provisioning  . . . . . . . . . . . . . .  7
     3.5.  Provisioning For Mesh-Groups . . . . . . . . . . . . . . .  7
   4.  Processing Rules . . . . . . . . . . . . . . . . . . . . . . .  7
     4.1.  ASSOCIATION Object . . . . . . . . . . . . . . . . . . . .  8
     4.2.  Extended ASSOCIATION Object  . . . . . . . . . . . . . . .  8
     4.3.  Rules For ASSOCIATION Object . . . . . . . . . . . . . . .  9
       4.3.1.  Teardown of Associated LSPs  . . . . . . . . . . . . . 10
       4.3.2.  Compatibility For ASSOCIATION Object . . . . . . . . . 10
     4.4.  Rules For REVERSE_LSP Object . . . . . . . . . . . . . . . 10
       4.4.1.  Teardown of Associated LSPs  . . . . . . . . . . . . . 11
       4.4.2.  Compatibility For REVERSE_LSP Object . . . . . . . . . 11
   5.  Message and Object Definitions . . . . . . . . . . . . . . . . 12
     5.1.  RSVP Message Formats . . . . . . . . . . . . . . . . . . . 12
     5.2.  ASSOCIATION Object Definition  . . . . . . . . . . . . . . 12
     5.3.  REVERSE_LSP Object Definition  . . . . . . . . . . . . . . 12
       5.3.1.  REVERSE_LSP Object Format  . . . . . . . . . . . . . . 12
       5.3.2.  REVERSE_LSP Subobjects . . . . . . . . . . . . . . . . 13
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
     6.1.  Association Types  . . . . . . . . . . . . . . . . . . . . 13
     6.2.  REVERSE_LSP Object . . . . . . . . . . . . . . . . . . . . 14
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   8.  Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 15
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16

 

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1.  Introduction

   The MPLS Transport Profile (MPLS-TP) requirements document [RFC5654]
   specifies that MPLS-TP MUST support associated bidirectional point-
   to-point Label Switched Paths (LSPs). These requirements are given in
   Section 2.1 (General Requirements), and are repeated below:

   7.  MPLS-TP MUST support associated bidirectional point-to-point
   LSPs.

   11.  The end points of an associated bidirectional LSP MUST be aware
   of the pairing relationship of the forward and reverse LSPs used to
   support the bidirectional service.

   12.  Nodes on the LSP of an associated bidirectional LSP where both
   the forward and backward directions transit the same node in the same
   (sub)layer as the LSP SHOULD be aware of the pairing relationship of
   the forward and the backward directions of the LSP.

   14.  MPLS-TP MUST support bidirectional LSPs with asymmetric
   bandwidth requirements, i.e., the amount of reserved bandwidth
   differs between the forward and backward directions.

   50.  The MPLS-TP control plane MUST support establishing associated
   bidirectional P2P LSP including configuration of protection functions
   and any associated maintenance functions.

   The above requirements are also repeated in [RFC6373].

   Furthermore, an associated bidirectional LSP is also useful for
   protection switching for Operations, Administrations and Maintenance
   (OAM) messages that require a return path.

   A variety of applications, such as Internet services and the return
   paths of OAM messages, exist and which may have different upstream
   and downstream bandwidth requirements. [RFC5654] specifies an
   asymmetric bandwidth requirement in Section 2.1 (General
   Requirements), and is repeated below:

   14.  MPLS-TP MUST support bidirectional LSPs with asymmetric
   bandwidth requirements, i.e., the amount of reserved bandwidth
   differs between the forward and backward directions.

   The approach for supporting asymmetric bandwidth co-routed
   bidirectional LSPs is defined in [RFC6387].

   The method of association and the corresponding Resource reSerVation
   Protocol (RSVP) ASSOCIATION object are defined in [RFC4872],
 

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   [RFC4873] and [RFC6689]. In that context, the ASSOCIATION object is
   used to associate a recovery LSP with the LSP it is protecting. This
   object also has broader applicability as a mechanism to associate
   RSVP states. [RFC6780] defines an Extended ASSOCIATION object that
   can be more generally applied for this purpose.

   This document specifies mechanisms for binding two reverse
   unidirectional LSPs into an associated bidirectional LSP. The
   association is achieved by defining new Association Types in the
   (Extended) ASSOCIATION object. RSVP extensions allow asymmetric
   upstream and downstream bandwidths for the bidirectional LSP.

2.  Conventions used in this document

   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].

3.  Overview

3.1.  Provisioning Model Overview

   This section provides an overview of the models for provisioning
   bidirectional LSPs.

   The associated bidirectional LSP's forward and reverse unidirectional
   LSPs are established, monitored, and protected independently as
   specified by [RFC5654]. Configuration information regarding the LSPs
   can be provided at one or both endpoints of the associated
   bidirectional LSP. Depending on the method chosen, there are two
   models of creating an associated bidirectional LSP; single sided
   provisioning, and double sided provisioning.

3.1.1.  Single Sided Provisioning

   For the single sided provisioning, the TE tunnel is configured only
   on one side. An LSP for this tunnel is initiated by the initiating
   endpoint with the (Extended) ASSOCIATION object inserted in the Path
   message. The other endpoint then creates the corresponding reverse TE
   tunnel and signals the reverse LSP in response to this.

3.1.2.  Double Sided Provisioning

   For the double sided provisioning, two unidirectional TE tunnels are
   configured independently on both sides. The LSPs for the tunnels are
   signaled with (Extended) ASSOCIATION objects inserted in the Path
   message by both sides to indicate that the two LSPs are to be
   associated to form a bidirectional LSP.
 

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3.2.  Association Signaling Overview

   This section provides an overview of the association signaling
   methods for the bidirectional LSPs.

   Three scenarios exist for binding two unidirectional LSPs together to
   form an associated bidirectional LSP. These are: 1) Neither
   unidirectional LSP exists, and both must be established. 2) Both
   unidirectional LSPs exist, but the association must be established.
   3) One LSP exists, but the reverse associated LSP must be
   established.

   In each of the situations described above, both provisioning models
   are applicable.

   Path Computation Element (PCE)-based approaches [RFC4655], may be
   used for path computation of an associated bidirectional LSP.
   However, these approaches are outside the scope of this document.

   Consider the topology described in Figure 1 (an example of associated
   bidirectional LSP). LSP1 from A to B, takes the path A,D,B and LSP2
   from B to A takes the path B,D,C,A. These two LSPs, once established
   and associated, form an associated bidirectional LSP between node A
   and node B.

                           LSP1 -->
                           A-------D-------B
                            \     / <-- LSP2
                             \   /
                              \ /
                               C

           Figure 1: An example of associated bidirectional LSP

3.2.1.  Single Sided Provisioning

   For the single sided provisioning model, creation of reverse LSP1 is
   triggered by LSP2 or creation of reverse LSP2 is triggered by LSP1.
   When creation of reverse LSP2 is triggered by LSP1, LSP1 is
   provisioned first (or refreshed if LSP1 already exists) at node A.
   LSP1 is then signaled with an (Extended) ASSOCIATION object inserted
   in the Path message, in which the Association Type indicating single
   sided provisioning. Upon receiving this Path message for LSP1, node B
   establishes reverse LSP2. The (Extended) ASSOCIATION object inserted
   in LSP2's Path message is the same as that received in LSP1's Path
   message.
 

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   A similar procedure is used if LSP2 is provisioned first at node B
   and the creation of reverse LSP1 is triggered by LSP2. In both cases,
   the two unidirectional LSPs are bound together to form an associated
   bidirectional LSP based on identical (Extended) ASSOCIATION objects
   in the two LSPs' Path messages.

3.2.2.  Double Sided Provisioning

   For the double sided provisioning model, both LSP1 and LSP2 are
   signaled independently with (Extended) ASSOCIATION object inserted in
   the Path message, in which the Association Type indicating double
   sided provisioning. In this case, the two unidirectional LSPs are
   bound together to form an associated bidirectional LSP based on
   identical (Extended) ASSOCIATION objects in the two LSPs' Path
   messages.

3.3.  Asymmetric Bandwidth Signaling Overview

   This section provides an overview of the methods for signaling
   asymmetric upstream and downstream bandwidths for the associated
   bidirectional LSPs.

3.3.1.  Single Sided Provisioning

   New REVERSE_LSP object applicable to the single sided provisioning
   model is defined in this document, in Section 5.3. When the single
   sided provisioning model is used, the existing SENDER_TSPEC object is
   added in the REVERSE_LSP object as a subobject in the initiating
   LSP's Path message to specify the reverse LSP's traffic parameters.
   As described in Section 5.3, addition of the REVERSE_LSP object also
   allows the initiating node to control the reverse LSP.

   Consider again the topology described in Figure 1, where the creation
   of reverse LSP2 is triggered by LSP1. Node A signals LSP1 with the
   (Extended) ASSOCIATION object with Association Type indicating single
   sided provisioning and inserts SENDER_TSPEC subobject in the
   REVERSE_LSP object in the Path message. Node B then establishes the
   LSP2 in the reverse direction using the asymmetric bandwidth thus
   specified by LSP1 and allows node A to control the reverse LSP2.

3.3.2.  Double Sided Provisioning

   When the double sided provisioning model is used, the two
   unidirectional LSPs are established with asymmetric bandwidths
   independently. However, these LSPs are associated purely based on the
   identical contents of their (Extended) ASSOCIATION objects.

 

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3.4.  Recovery LSP Overview

   Consider again the topology described in Figure 1, where LSP1 and
   LSP2 form an associated bidirectional LSP. Under a recovery scenario,
   a third LSP (LSP3) may be used to protect LSP1 on node A. LSP3 may be
   established before or after the failure occurs. LSP3 in this case
   belongs to the same TE tunnel as LSP1 on node A.

   When node A detects that LSP1 has failed or needs to be reoptimized,
   LSP3 is initialized or refreshed with the (Extended) ASSOCIATION
   object (including the Association Type) inherited from LSP1's Path
   message. If LSP3 is the protecting LSP [RFC4872], the PROTECTION
   object [RFC4872] is also inherited from LSP1. In any case, LSP2 and
   LSP3 are associated to form an associated bidirectional LSP based on
   the identical (Extended) ASSOCIATION objects in their Path messages.

3.4.1.  Single Sided Provisioning

   When the single sided provisioning model is used, recovery LSP3 on
   node A triggers the creation of reverse recovery LSP4 on node B as
   described in Section 3.2.1 of this document. However, node A and node
   B perform LSP recovery actions independently [RFC5654].

3.4.2.  Double Sided Provisioning

   When the double sided provisioning model is used, recovery LSP3 on
   node A may or may not have associated reverse recovery LSP4 on node
   B. In any case, node A and node B perform LSP recovery actions
   independently [RFC5654].

3.5.  Provisioning For Mesh-Groups

   TE mesh-groups are defined in [RFC4972]. In order to enable
   unambiguous association of the mesh-group's bidirectional LSPs, the
   information carried in the (Extended) ASSOCIATION object,
   specifically the contents of the Association Source and Identifier
   fields are provisioned for the mesh-groups using the models specified
   in Section 3.1.1 and 3.1.2 of this document, namely, single sided and
   double sided provisioning.

4.  Processing Rules

   In general, the processing rules for the ASSOCIATION object are as
   specified in [RFC4872] and Extended ASSOCIATION object are specified
   in [RFC6780]. Following sections describe the rules for processing
   (Extended) ASSOCIATION and REVERSE_LSP objects for associated
   bidirectional LSPs.

 

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4.1.  ASSOCIATION Object

   The ASSOCIATION object is populated using the rules defined below for
   associating two reverse unidirectional LSPs to form a bidirectional
   LSP.

   Association Types:

      In order to bind two reverse unidirectional LSPs to be an
      associated bidirectional LSP, the Association Type MUST be set to
      indicate either single sided or double sided LSPs.

      The new Association Types are defined as follows:

      Value      Type

      -----      -----
      4 (TBD)    Double Sided Associated Bidirectional LSPs (D)
      5 (TBD)    Single Sided Associated Bidirectional LSPs (A)

   Association ID:

      For both single sided and double sided provisioning, Association
      ID MUST be set to a value assigned by the node that originates the
      association for the bidirectional LSP.

   Association Source:

      For double sided provisioning, Association Source MUST be set to
      an address selected by the node that originates the association
      for the bidirectional LSP (which may be a management entity.)

      For single sided provisioning, Association Source MUST be set to
      an address assigned to the node that originates the LSP.

4.2.  Extended ASSOCIATION Object

   The Extended ASSOCIATION object is populated using the rules defined
   below for associating two reverse unidirectional LSPs to form a
   bidirectional LSP.

   The Association Type, Association ID and Association Source MUST be
   set as defined for the ASSOCIATION object in Section 4.1.

   Global Association Source:

      For both single sided and double sided provisioning, Global
 

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      Association Source, when used, MUST be set to the Global_ID
      [RFC6370] of the node that originates the association for the
      bidirectional LSP.

   Extended Association ID:

      For both single sided and double sided provisioning, Extended
      Association ID, when used, MUST be set to a value selected by the
      node that originates the association for the bidirectional LSP.

4.3.  Rules For ASSOCIATION Object

   The ASSOCIATION object is inserted in the Path message of the LSP
   using the rules defined in this document for associating two reverse
   unidirectional LSPs to form an associated bidirectional LSP.

   For associating two unidirectional LSPs to form a bidirectional LSP,
   if either Global Association Source or Extended Association Address
   is required, then an Extended ASSOCIATION object [RFC6780] is
   inserted in the Path message of the LSP instead of the ASSOCIATION
   object.

   Association Type in the (Extended) ASSOCIATION object MUST be set to
   the "Single Sided Associated Bidirectional LSPs" or "Double Sided
   Associated Bidirectional LSPs" based on the single sided or double
   sided provisioning model used for the LSPs. ASSOCIATION or Extended
   ASSOCIATION objects with both single sided and double sided
   Association Types MUST NOT be added in the same Path message.

   As described in [RFC6780], association of the LSPs is based on
   matching ASSOCIATION objects in Path or Resv. Upstream initialized
   association is represented in (Extended) ASSOCIATION object carried
   in the Path message and downstream initialized association is
   represented in (Extended) ASSOCIATION object carried in the Resv
   message. The new Association Types defined in this document are only
   used in upstream initialized association. Thus they can appear in the
   (Extended) ASSOCIATION object in Path message only.

   The procedures associated with the processing of the (Extended)
   ASSOCIATION objects are discussed in [RFC6780]. [RFC6780] specifies
   that in the absence of Association Type-specific rule for identifying
   association, the included (Extended) ASSOCIATION objects in the LSPs
   MUST be identical in order for an association to be formed. This
   document adds no specific rules for the new Association Types
   defined, and the determination of LSP association therefore proceeds
   as specified in [RFC6780].

   LSP recovery as defined in [RFC4872] and [RFC4873] is not impacted by
 

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   this document. The recovery mechanisms defined in [RFC4872] and
   [RFC4873] rely on the use of ASSOCIATION objects, but use a different
   value for Association Type; multiple ASSOCIATION objects MAY exist in
   the LSP Path message and MAY coexist with the procedures defined in
   this document.

   As specified in [RFC4872], an endpoint node that does not support the
   new Association Types defined in this document MUST return a PathErr
   message with the error code "LSP Admission Failure" (value 01 as
   defined in [RFC2205]) and the sub-code "Bad Association Type" (value
   5 as defined in [RFC4872]).

4.3.1.  Teardown of Associated LSPs

   Associated bidirectional LSP teardown follows the standard procedures
   defined in [RFC3209] and [RFC3473] either without or with the
   administrative status. Note that teardown procedures of the
   unidirectional LSPs forming an associated bidirectional LSP are
   independent of each other, so it is possible that while one LSP
   follows graceful teardown with administrative status, the reverse LSP
   is torn down without administrative status (using
   PathTear/ResvTear/PathErr with state removal).

   For the single sided provisioning where the REVERSE_LSP object is not
   signaled, the teardown of the initiating LSP SHOULD trigger the
   teardown of the reverse LSP, however, teardown of the reverse LSP MAY
   NOT trigger the teardown of the initiating LSP (which may depend on
   the local policy).

   For the double sided provisioning, the teardown of one unidirectional
   LSP SHOULD not trigger teardown of the reverse LSP.

4.3.2.  Compatibility For ASSOCIATION Object

   The ASSOCIATION object has been defined in [RFC4872] and the Extended
   ASSOCIATION object has been defined in [RFC6780], both with class
   numbers in the form 11bbbbbb, which ensures compatibility with
   non-supporting nodes. Per [RFC2205], such nodes will ignore the
   object but forward it without modification.

   Operators wishing to use a function supported by a particular
   association type SHOULD ensure that the type is supported on any node
   that is expected to act on the association [RFC6780].

4.4.  Rules For REVERSE_LSP Object

   A node initiating a Path message containing an ASSOCIATION or
   Extended ASSOCIATION object with the Association Type set to "Single
 

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   Sided Associated Bidirectional LSPs" MAY include a REVERSE_LSP object
   in the Path message of the LSP when it wishes to control the reverse
   LSP on the other endpoint node and to specify the reverse LSP's
   traffic parameters.

   The REVERSE_LSP subobject MAY contain any of the specified subobjects
   which the initiating node desires to have included in the Path
   message for the associated reverse LSP. A REVERSE_LSP object MUST
   contain at least one subobject.

   A node receiving a valid Path message containing a REVERSE_LSP object
   that is not the endpoint node for the LSP being signaled MUST forward
   the REVERSE_LSP object unchanged in the outgoing Path message.

   The endpoint node upon receiving a Path message containing a
   REVERSE_LSP object triggers to establish the reverse LSP according to
   the received parameters in the REVERSE_LSP object. The receiver
   endpoint node MUST convert the subobjects of the REVERSE_LSP object
   into the corresponding objects to be carried in the reverse LSP's
   Path message.

   A Path message that does not contain an ASSOCIATION or Extended
   ASSOCIATION object with the Association Type set to "Single Sided
   Associated Bidirectional LSPs" MUST NOT contain a REVERSE_LSP object.

4.4.1.  Teardown of Associated LSPs

   If initiating node controlling the reverse LSP using the procedure
   defined in this document, wishes to tear down the associated
   bidirectional LSP, the initiating node sends a PathTear message to
   the other endpoint, the other endpoint MUST trigger to tear down the
   reverse associated LSP.

4.4.2.  Compatibility For REVERSE_LSP Object

   The REVERSE_LSP object is defined with class numbers in the form
   11bbbbbb, which ensures compatibility with non-supporting nodes. Per
   [RFC2205], such nodes will ignore the object but forward it without
   modification.

   Per [RFC2205], an endpoint node that does not support the REVERSE_LSP
   C-Type MAY generate an "Unknown object C-Type" error. This error will
   propagate to the initiating node for standard error processing.

 

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5.  Message and Object Definitions

5.1.  RSVP Message Formats

   This section presents the RSVP message-related formats as modified by
   this document. Unmodified RSVP message formats are not listed.

   The format of a Path message is as follows:

      <Path Message> ::= <Common Header> [ <INTEGRITY> ]
                         [ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ... ]
                         [ <MESSAGE_ID> ]
                         <SESSION> <RSVP_HOP>
                         <TIME_VALUES>
                         [ <EXPLICIT_ROUTE> ]
                         <LABEL_REQUEST>
                         [ <PROTECTION> ]
                         [ <LABEL_SET> ... ]
                         [ <SESSION_ATTRIBUTE> ]
                         [ <NOTIFY_REQUEST> ... ]
                         [ <ADMIN_STATUS> ]
                         [ <ASSOCIATION> ... ]
                         [ <REVERSE_LSP]
                         [ <POLICY_DATA> ... ]
                         <sender descriptor>

   The format of the <sender descriptor> is not modified by this
   document.

5.2.  ASSOCIATION Object Definition

   The ASSOCIATION object is defined in [RFC4872]. The Extended
   ASSOCIATION object is defined in [RFC6780]. Other than the two new
   Association Types defined in this document, the (Extended)
   ASSOCIATION object definition is not modified by this document.

5.3.  REVERSE_LSP Object Definition

5.3.1.  REVERSE_LSP Object Format

   The information of the reverse LSP is specified via the REVERSE_LSP
   object. This is an optional object carried in a Path message with
   class numbers in the form 11bbbbbb and has the following format:

   Class = TBD (of the form 11bbbbbb), C_Type =  (TBD)

 

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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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                        (Subobjects)                          //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

5.3.2.  REVERSE_LSP Subobjects

   The contents of a REVERSE_LSP object is a variable length series of
   subobjects. The subobjects permitted in the REVERSE_LSP object are
   previously defined as Path message subobjects, and have the same
   format and order in the REVERSE_LSP object.

   Examples of the Path message subobjects carried in the REVERSE_LSP
   object are (but not limited to):

    - SENDER_TSPEC [RFC2205]
    - EXPLICIT_ROUTE object (ERO) [RFC3209]
    - SESSION_ATTRIBUTE object [RFC3209]
    - ADMIN_STATUS object [RFC3473]
    - LSP_ATTRIBUTES object [RFC5420]
    - LSP_REQUIRED_ATTRIBUTES object [RFC5420]
    - PROTECTION object [RFC3473] [RFC4872]

6.  IANA Considerations

   IANA is requested to administer assignment of new values for
   namespace defined in this document and summarized in this section.

6.1.  Association Types

   New Association Types for ASSOCIATION and Extended ASSOCIATION
   objects are defined in this document as follows:

   Value      Type
   -----      -----
   4 (TBD)    Double Sided Associated Bidirectional LSPs (D)
   5 (TBD)    Single Sided Associated Bidirectional LSPs (A)

 

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6.2.  REVERSE_LSP Object

   A new class type for REVERSE_LSP has been requested in the 11bbbbbb
   range (TBD) with the following definition:

   Class Types or C-types (TBD), Value (TBD): REVERSE_LSP Object

   There are no other IANA considerations introduced by this document.

7.  Security Considerations

   This document introduces two new Association Types, however, no new
   security issues relating to the (Extended) ASSOCIATION object are
   introduced.

   The procedures defined in this document result in an increased state
   information carried in signaling messages. The presence of the
   REVERSE_LSP object necessarily provides more information about the
   LSPs. Thus, in the event of the interception of a signaling message,
   slightly more information about the state of the network could be
   deduced than was previously the case. This is judged to be a very
   minor security risk as this information is already available via
   routing.

   Otherwise, this document introduces no additional security
   considerations. For a general discussion on MPLS and GMPLS related
   security issues, see the MPLS/GMPLS security framework [RFC5920].

8.  Acknowledgement

   The authors would like to thank Lou Berger and George Swallow for
   their great guidance in this work, Jie Dong for the discussion of
   recovery, Lamberto Sterling for his valuable comments on the section
   of asymmetric bandwidths, Daniel King for the review of the document,
   Attila Takacs for the discussion of the provisioning model. At the
   same time, the authors would also like to acknowledge the
   contributions of Bo Wu, Xihua Fu, Lizhong Jin for the initial
   discussions, and Wenjuan He for the prototype implementation. The
   authors would also like to thank Siva Sivabalan, Eric Osborne and
   Robert Sawaya for the discussions on the ASSOCIATION object. The
   authors would like to thank Matt Hartley for providing useful
   suggestions on the document.

 

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9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2205]  Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.

   [RFC4872]  Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE
              Extensions in Support of End-to-End Generalized Multi-
              Protocol Label Switching (GMPLS) Recovery", RFC 4872, May
              2007.

   [RFC4873]  Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
              "GMPLS Segment Recovery", RFC 4873, May 2007.

   [RFC6780]  Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP
              Association Object Extensions", RFC 6780, October 2012.

9.2.  Informative References

   [RFC3473]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
              Element (PCE)-Based Architecture", RFC 4655, August 2006.

   [RFC4972]  Vasseur, JP., Leroux, JL., Yasukawa, S., Previdi, S.,
              Psenak, P., Mabbey, P., "Routing Extensions for Discovery
              of Multiprotocol (MPLS) Label Switch Router (LSR) Traffic
              Engineering (TE) Mesh Membership", RFC 4972, July 2007.

   [RFC5654]  Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
              and S. Ueno, "Requirements of an MPLS Transport Profile",
              RFC 5654, September 2009.

   [RFC5920]  Fang, L., "Security Framework for MPLS and GMPLS
              Networks", RFC 5920, July 2010.

 

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   [RFC6370]  Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
              Profile (MPLS-TP) Identifiers", RFC 6370, September 2011.

   [RFC6373]  Andersson, L., Berger, L., Fang, L., Bitar, N., and E.
              Gray, "MPLS Transport Profile (MPLS-TP) Control Plane
              Framework", RFC 6373, September 2011.

   [RFC6387]  Takacs, A., Berger, L., Caviglia, D., Fedyk, D., and J.
              Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
              Switched Paths (LSPs)", RFC 6387, September 2011.

   [RFC6689]  Berger, L., "Usage of The RSVP Association Object", RFC
              6689, July 2012.

Authors' Addresses

   Fei Zhang (editor)
   ZTE

   Email: zhang.fei3@zte.com.cn

   Ruiquan Jing
   China Telecom

   Email: jingrq@ctbri.com.cn

   Fan Yang
   ZTE

   Email: yang.fan240347@gmail.com

   Weilian Jiang
   ZTE

   Email: jiang.weilian@gmail.com

   Rakesh Gandhi (editor)
   Cisco Systems

   Email: rgandhi@cisco.com

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