path: root/doc/rfc/rfc6780.txt

Internet Engineering Task Force (IETF)                         L. Berger
Request for Comments: 6780                                          LabN
Updates: 2205, 3209, 3473, 4872                           F. Le Faucheur
Category: Standards Track                                   A. Narayanan
ISSN: 2070-1721                                                    Cisco
                                                            October 2012


                   RSVP ASSOCIATION Object Extensions

Abstract

   The RSVP ASSOCIATION object was defined in the context of GMPLS-
   controlled Label Switched Paths (LSPs).  In this context, the object
   is used to associate recovery LSPs with the LSP they are protecting.
   This object also has broader applicability as a mechanism to
   associate RSVP state.  This document defines how the ASSOCIATION
   object can be more generally applied.  This document also defines
   Extended ASSOCIATION objects that, in particular, can be used in the
   context of the MPLS Transport Profile (MPLS-TP).  This document
   updates RFC 2205, RFC 3209, and RFC 3473.  It also generalizes the
   definition of the Association ID field defined in RFC 4872.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6780.















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Copyright Notice

   Copyright (c) 2012 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
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................4
   2. Generalized Association ID Field Definition .....................4
   3. Non-GMPLS and Non-Recovery Usage ................................4
      3.1. Upstream Initiated Association .............................5
           3.1.1. Path Message Format .................................5
           3.1.2. Path Message Processing .............................6
      3.2. Downstream Initiated Association ...........................7
           3.2.1. Resv Message Format .................................8
           3.2.2. Resv Message Processing .............................8
      3.3. Association Types ..........................................9
           3.3.1. Resource Sharing Association Type ...................9
           3.3.2. Unknown Association Types ..........................10
   4. IPv4 and IPv6 Extended ASSOCIATION Objects .....................10
      4.1. IPv4 and IPv6 Extended ASSOCIATION Object Format ..........11
      4.2. Processing ................................................13
   5. Compatibility ..................................................14
   6. Security Considerations ........................................14
   7. IANA Considerations ............................................15
      7.1. IPv4 and IPv6 Extended ASSOCIATION Objects ................15
      7.2. Resource Sharing Association Type .........................15
   8. Acknowledgments ................................................16
   9. References .....................................................16
      9.1. Normative References ......................................16
      9.2. Informative References ....................................16









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1.  Introduction

   End-to-end and segment recovery are defined for GMPLS-controlled
   Label Switched Paths (LSPs) in [RFC4872] and [RFC4873], respectively.
   Both definitions use the ASSOCIATION object to associate recovery
   LSPs with the LSP they are protecting.  Additional narrative on how
   such associations are to be identified is provided in [RFC6689].

   This document expands the possible usage of the ASSOCIATION object to
   non-GMPLS and non-recovery contexts.  The expanded usage applies
   equally to GMPLS LSPs [RFC3473], MPLS LSPs [RFC3209], and non-LSP
   RSVP sessions [RFC2205] [RFC2207] [RFC3175] [RFC4860].  This document
   also reviews how associations should be made in the case in which the
   object is carried in a Path message; additionally, it defines usage
   with Resv messages.  This section also discusses usage of the
   ASSOCIATION object outside the context of GMPLS LSPs.

   Some examples of non-LSP association being used to enable resource
   sharing are:

   o  Voice Call-Waiting:

      A bidirectional voice call between two endpoints, A and B, is
      signaled using two separate unidirectional RSVP reservations for
      the flows A->B and B->A.  If endpoint A wishes to put the A-B call
      on hold and join a separate A-C call, it is desirable that network
      resources on common links be shared between the A-B and A-C calls.
      The B->A and C->A subflows of the call can share resources using
      existing RSVP sharing mechanisms, but only if they use the same
      destination IP addresses and ports.  Since by definition, the RSVP
      reservations for the subflows A->B and A->C of the call must have
      different IP addresses in the SESSION objects, this document
      defines a new mechanism to associate the subflows and allow them
      to share resources.

   o  Voice Shared Line:

      A voice shared line is a single number that rings multiple
      endpoints (which may be geographically diverse), such as phone
      lines to a manager's desk and to their assistant.  A Voice over IP
      (VoIP) system that models these calls as multiple point-to-point
      unicast pre-ring reservations would result in significantly over-
      counting bandwidth on shared links, since RSVP unicast
      reservations to different endpoints cannot share bandwidth.  So, a
      new mechanism is defined in this document to allow separate
      unicast reservations to be associated and to share resources.





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   o  Symmetric NAT:

      RSVP permits sharing of resources between multiple flows addressed
      to the same destination D, even from different senders S1 and S2.
      However, if D is behind a NAT operating in symmetric mode
      [RFC5389], it is possible that the destination port of the flows
      S1->D and S2->D may be different outside the NAT.  In this case,
      these flows cannot share resources using RSVP, since the SESSION
      objects for these two flows outside the NAT have different
      destination ports.  This document defines a new mechanism to
      associate these flows and allow them to share resources.

   In order to support the wider usage of the ASSOCIATION object, this
   document generalizes the definition of the Association ID field
   defined in RFC 4872.  This generalization has no impact on existing
   implementations.  When using the procedures defined below,
   association is identified based on exact ASSOCIATION object matching.
   Some of the other matching mechanisms defined in RFC 4872, e.g.,
   matching based on Session IDs, are not generalized.  This document
   allows for, but does not specify, association type-specific
   processing.

   This document also defines the Extended ASSOCIATION objects that can
   be used in the context of MPLS-TP.  The scope of the Extended
   ASSOCIATION objects is not limited to MPLS-TP.

1.1.  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].

2.  Generalized Association ID Field Definition

   The Association ID field is carried in the IPv4 and IPv6 ASSOCIATION
   objects defined in [RFC4872].  The [RFC4872] definition of the field
   reads:

      A value assigned by the LSP head-end.  When combined with the
      Association Type and Association Source, this value uniquely
      identifies an association.

   This document allows for the origination of ASSOCIATION objects by
   nodes other than "the LSP head-end".  As such, the definition of the
   Association ID field needs to be generalized to accommodate such
   usage.  This document defines the Association ID field of the IPv4
   and IPv6 ASSOCIATION objects as:




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      A value assigned by the node that originated the association.
      When combined with the other fields carried in the object, this
      value uniquely identifies an association.

   This change in definition does not impact the procedures or
   mechanisms defined in [RFC4872] or [RFC4873], nor does it impact the
   existing implementations of [RFC4872] or [RFC4873].

3.  Non-GMPLS and Non-Recovery Usage

   While the ASSOCIATION object [RFC4872] is defined in the context of
   GMPLS recovery, the object can have wider application.  [RFC4872]
   defines the object to be used to "associate LSPs with each other",
   and then defines an Association Type field to identify the type of
   association being identified.  It also specifies that the Association
   Type field is to be considered when determining association, i.e.,
   there may be type-specific association rules.  As defined by
   [RFC4872] and reviewed in [RFC6689], this is the case for recovery
   type ASSOCIATION objects.  [RFC6689], notably the text related to
   resource sharing types, can also be used as the foundation for a
   generic method for associating LSPs when there is no type-specific
   association defined.

   The remainder of this section defines the general rules to be
   followed when processing ASSOCIATION objects.  Object usage in both
   Path and Resv messages is discussed.  The usage applies equally to
   GMPLS LSPs [RFC3473], MPLS LSPs [RFC3209], and non-LSP RSVP sessions
   [RFC2205] [RFC2207] [RFC3175] [RFC4860].  As described below,
   association is always done based on matching either Path state to
   Path state, or Resv state to Resv state, but not Path state to Resv
   State.  This section applies to the ASSOCIATION objects defined in
   [RFC4872].

3.1.  Upstream-Initiated Association

   Upstream-initiated association is represented in ASSOCIATION objects
   carried in Path messages and can be used to associate RSVP Path state
   across MPLS Tunnels / RSVP sessions.  (Note, per [RFC3209], an MPLS
   tunnel is represented by an RSVP SESSION object, and multiple LSPs
   may be represented within a single tunnel.)  Cross-LSP association
   based on Path state is defined in [RFC4872].  This section extends
   that definition by specifying generic association rules and usage for
   non-LSP uses.  This section does not modify processing required to
   support [RFC4872] and [RFC4873], which is reviewed in Section 3 of
   [RFC6689].  The use of an ASSOCIATION object in a single session is
   not precluded.





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3.1.1.  Path Message Format

   This section provides the Backus-Naur Form (BNF), see [RFC5511], for
   Path messages containing ASSOCIATION objects.  BNF is provided for
   both MPLS and for non-LSP session usage.  Unmodified RSVP message
   formats and some optional objects are not listed.

   The formats for MPLS and GMPLS sessions are unmodified from [RFC4872]
   and can be represented based on the BNF in [RFC3209] as:

         <Path Message> ::= <Common Header> [ <INTEGRITY> ]
                            <SESSION> <RSVP_HOP>
                            <TIME_VALUES>
                            [ <EXPLICIT_ROUTE> ]
                            <LABEL_REQUEST>
                            [ <SESSION_ATTRIBUTE> ]
                            [ <ASSOCIATION> ... ]
                            [ <POLICY_DATA> ... ]
                            <sender descriptor>

   The format for non-LSP sessions as based on the BNF in [RFC2205] is:

         <Path Message> ::= <Common Header> [ <INTEGRITY> ]
                            <SESSION> <RSVP_HOP>
                            <TIME_VALUES>
                           [ <ASSOCIATION> ... ]
                           [ <POLICY_DATA> ... ]
                           [ <sender descriptor> ]

   In general, relative ordering of ASSOCIATION objects with respect to
   each other, as well as with respect to other objects, is not
   significant.  Relative ordering of ASSOCIATION objects of the same
   type SHOULD be preserved by transit nodes.

3.1.2.  Path Message Processing

   This section is based on, and extends, the processing rules described
   in [RFC4872] and [RFC4873], which is reviewed in [RFC6689].  This
   section applies equally to GMPLS LSPs, MPLS LSPs, and non-LSP session
   state.  Note, as previously stated, this section does not modify
   processing required to support [RFC4872] and [RFC4873].

   A node sending a Path message chooses when an ASSOCIATION object is
   to be included in the outgoing Path message.  To indicate association
   between multiple sessions, an appropriate ASSOCIATION object MUST be
   included in the outgoing Path messages corresponding to each of the
   associated sessions.  In the absence of Association-Type-specific
   rules for identifying association, the included ASSOCIATION object



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   MUST be identical.  When there is an Association-Type-specific
   definition of association rules, the definition SHOULD allow for
   association based on identical ASSOCIATION objects.  This document
   does not define any Association-Type-specific rules.  (See Section 3
   of [RFC6689] for a review of Association-Type-specific rules derived
   from [RFC4872].)

   When creating an ASSOCIATION object, the originator MUST format the
   object as defined in Section 16.1 of [RFC4872].  The originator MUST
   set the Association Type field based on the type of association being
   identified.  The Association ID field MUST be set to a value that
   uniquely identifies the specific association within the context of
   the Association Source field.  The Association Source field MUST be
   set to a unique address assigned to the node originating the
   association.

   A downstream node can identify an upstream-initiated association by
   performing the following checks.  When a node receives a Path
   message, it MUST check each ASSOCIATION object received in the Path
   message to determine if the object contains an Association Type field
   value supported by the node.  For each ASSOCIATION object containing
   a supported association type, the node MUST then check to see if the
   object matches an ASSOCIATION object received in any other Path
   message.  To perform this matching, a node MUST examine the Path
   state of all other sessions and compare the fields contained in the
   newly received ASSOCIATION object with the fields contained in the
   Path state's ASSOCIATION objects.  An association is deemed to exist
   when the same values are carried in all fields of the ASSOCIATION
   objects being compared.  Type-specific processing of ASSOCIATION
   objects is outside the scope of this document.

   Note that as more than one association may exist, the described
   matching MUST continue after a match is identified and MUST be
   performed against all local Path state.  It is also possible for
   there to be no match identified.

   Unless there are type-specific processing rules, downstream nodes
   MUST forward all ASSOCIATION objects received in a Path message in
   any corresponding outgoing Path messages without modification.  This
   processing MUST be followed for unknown Association Type field
   values.

3.2.  Downstream-Initiated Association

   Downstream-initiated association is represented in ASSOCIATION
   objects carried in Resv messages and can be used to associate RSVP
   Resv state across MPLS Tunnels/RSVP sessions.  Cross-LSP association,
   based on Path state, is defined in [RFC4872].  This section defines



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   cross-session association based on Resv state.  This section places
   no additional requirements on implementations supporting [RFC4872]
   and [RFC4873].  Note, the use of an ASSOCIATION object in a single
   session is not precluded.

3.2.1.  Resv Message Format

   This section provides the Backus-Naur Form (BNF), see [RFC5511], for
   Resv messages containing ASSOCIATION objects.  BNF is provided for
   both MPLS and for non-LSP session usage.  Unmodified RSVP message
   formats and some optional objects are not listed.

   The formats for MPLS, GMPLS, and non-LSP sessions are identical and
   are represented based on the BNF in [RFC2205] and [RFC3209]:

         <Resv Message> ::= <Common Header> [ <INTEGRITY> ]
                            <SESSION>  <RSVP_HOP>
                            <TIME_VALUES>
                            [ <RESV_CONFIRM> ]  [ <SCOPE> ]
                            [ <ASSOCIATION> ... ]
                            [ <POLICY_DATA> ... ]
                            <STYLE> <flow descriptor list>

   Relative ordering of ASSOCIATION objects with respect to each other,
   as well as with respect to other objects, is not currently
   significant.  Relative ordering of ASSOCIATION objects of the same
   type SHOULD be preserved by transit nodes.

3.2.2.  Resv Message Processing

   This section applies equally to GMPLS LSPs, MPLS LSPs, and non-LSP
   session state.

   A node sending a Resv message chooses when an ASSOCIATION object is
   to be included in the outgoing Resv message.  A node that wishes to
   allow upstream nodes to associate Resv state across RSVP sessions
   MUST include an ASSOCIATION object in the outgoing Resv messages
   corresponding to the RSVP sessions to be associated.  In the absence
   of Association-Type-specific rules for identifying association, the
   included ASSOCIATION objects MUST be identical.  When there is an
   Association-Type-specific definition of association rules, the
   definition SHOULD allow for association based on identical
   ASSOCIATION objects.  This document does not define any Association-
   Type-specific rules.

   When creating an ASSOCIATION object, the originator MUST format the
   object as defined in Section 16.1 of [RFC4872].  The originator MUST
   set the Association Type field based on the type of association being



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   identified.  The Association ID field MUST be set to a value that
   uniquely identifies the specific association within the context of
   the Association Source field.  The Association Source field MUST be
   set to a unique address assigned to the node originating the
   association.

   An upstream node can identify a downstream-initiated association by
   performing the following checks.  When a node receives a Resv
   message, it MUST check each ASSOCIATION object received in the Resv
   message to determine if the object contains an Association Type field
   value supported by the node.  For each ASSOCIATION object containing
   a supported association type, the node MUST then check to see if the
   object matches an ASSOCIATION object received in any other Resv
   message.  To perform this matching, a node MUST examine the Resv
   state of all other sessions and compare the fields contained in the
   newly received ASSOCIATION object with the fields contained in the
   Resv state's ASSOCIATION objects.  An association is deemed to exist
   when the same values are carried in all fields of the ASSOCIATION
   objects being compared.  Type-specific processing of ASSOCIATION
   objects is outside the scope of this document.

   Note that as more than one association may exist, the described
   matching MUST continue after a match is identified and MUST be
   performed against all local Resv state.  It is also possible for
   there to be no match identified.

   Unless there are type-specific processing rules, upstream nodes MUST
   forward all ASSOCIATION objects received in a Resv message in any
   corresponding outgoing Resv messages without modification.  This
   processing MUST be followed for unknown Association Type field
   values.

3.3.  Association Types

   Two association types are currently defined: recovery and resource
   sharing.  Recovery type association is only applicable within the
   context of recovery [RFC4872] [RFC4873].  Resource sharing is
   applicable to any context and its general use is defined in this
   section.

3.3.1.  Resource Sharing Association Type

   The Resource Sharing Association Type was defined in [RFC4873] and
   was defined within the context of GMPLS and upstream-initiated
   association.  This section presents a definition of the resource
   sharing association that allows for its use with any RSVP session
   type and in both Path and Resv messages.  This definition is
   consistent with the definition of the resource sharing association



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   type in [RFC4873] and no changes are required by this section in
   order to support [RFC4873].  The Resource Sharing Association Type
   MUST be supported by any implementation compliant with this document.

   The Resource Sharing Association Type is used to enable resource
   sharing across RSVP sessions.  Per [RFC4873], resource sharing uses
   the Association Type field value of 2.  ASSOCIATION objects with an
   Association Type with the value Resource Sharing MAY be carried in
   Path and Resv messages.  Association for the Resource Sharing type
   MUST follow the procedures defined in Section 3.1.2 for upstream-
   initiated (Path message) association and Section 3.2.1 for
   downstream-initiated (Resv message) association.  There are no type-
   specific association rules, processing rules, or ordering
   requirements.  Note that, as is always the case with association as
   enabled by this document, no associations are made across Path and
   Resv state.

   Once an association is identified, resources MUST be considered as
   shared across the identified sessions by the admission-control
   function.  Since the implementation specifics of the admission-
   control function is outside the scope of RSVP, we observe that how
   resource sharing is actually reflected may vary according to specific
   implementations (e.g., depending on the specific admission-control
   and resource-management algorithm, or on how local policy is taken
   into account).

3.3.2.  Unknown Association Types

   As required by Sections 3.1.2 and 3.2.2 above, a node that receives
   an ASSOCIATION object containing an unknown ASSOCIATION type forwards
   all received ASSOCIATION objects as defined above.  The node MAY also
   identify associations per the defined processing, e.g., to make this
   information available via a management interface.

4.  IPv4 and IPv6 Extended ASSOCIATION Objects

   [RFC4872] defines the IPv4 ASSOCIATION object and the IPv6
   ASSOCIATION object.  As defined, these objects each contain an
   Association Source field and a 16-bit Association ID field.  As
   previously described, the contents of the object uniquely identify an
   association.  Because the Association ID field is a 16-bit field, an
   association source can allocate up to 65536 different associations
   and no more.  There are scenarios where this number is insufficient
   (for example, where the association identification is best known and
   identified by a fairly centralized entity, and therefore may be
   involved in a large number of associations).





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   An additional case that cannot be supported using the existing
   ASSOCIATION objects is presented by MPLS-TP LSPs.  Per [RFC6370],
   MPLS-TP LSPs can be identified based on an operator-unique global
   identifier.  As defined in [RFC6370], "global identifier", or
   Global_ID, is based on [RFC5003] and includes the operator's
   Autonomous System Number (ASN).

   This section defines new ASSOCIATION objects to support extended
   identification in order to address the previously described
   limitations.  Specifically, the IPv4 Extended ASSOCIATION object and
   IPv6 Extended ASSOCIATION object are defined below.  Both new objects
   include the fields necessary to enable identification of a larger
   number of associations as well as MPLS-TP-required identification.

   The IPv4 Extended ASSOCIATION object and IPv6 Extended ASSOCIATION
   object SHOULD be supported by an implementation compliant with this
   document.  The processing rules for the IPv4 and IPv6 Extended
   ASSOCIATION object are described below and are based on the rules for
   the IPv4 and IPv6 ASSOCIATION objects as previously described.

4.1.  IPv4 and IPv6 Extended ASSOCIATION Object Format

   The IPv4 Extended ASSOCIATION object (Class-Num of the form 11bbbbbb
   with value = 199, C-Type = 3) has the format:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Length             | Class-Num(199)|  C-Type (3)   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       Association Type        |       Association ID          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                    IPv4 Association Source                    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Global Association Source                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                               .                               :
      :                    Extended Association ID                    :
      :                               .                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+











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   The IPv6 Extended ASSOCIATION object (Class-Num of the form 11bbbbbb
   with value = 199, C-Type = 4) has the format:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Length             | Class-Num(199)|  C-Type (4)   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       Association Type        |       Association ID          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                    IPv6 Association Source                    |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Global Association Source                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                               .                               :
      :                    Extended Association ID                    :
      :                               .                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Association Type: 16 bits

      Same as for IPv4 and IPv6 ASSOCIATION objects, see [RFC4872].

   Association ID: 16 bits

      Same as for IPv4 and IPv6 ASSOCIATION objects, see Section 2.

   Association Source: 4 or 16 bytes

      Same as for IPv4 and IPv6 ASSOCIATION objects, see [RFC4872].

   Global Association Source: 4 bytes

      This field contains a value that is a unique global identifier or
      the special value zero (0).  When non-zero and not overridden by
      local policy, the Global_ID as defined in [RFC6370] SHALL be used.
      The special value zero indicates that no global identifier is
      present.  Use of the special value zero SHOULD be limited to
      entities contained within a single operator.

      If the Global Association Source field value is derived from a
      2-octet ASN, then the two high-order octets of this 4-octet field
      MUST be set to zero.





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   Extended Association ID: variable, 4-byte aligned

      This field contains data that is additional information to support
      unique identification.  The length and contents of this field is
      scoped by the Association Source.  The length of this field is
      derived from the object Length field and as such MUST have a
      length of zero or be 4-byte aligned.  A length of zero indicates
      that this field is omitted.

4.2.  Processing

   The processing of an IPv4 or IPv6 Extended ASSOCIATION object MUST be
   identical to the processing of an IPv4 or IPv6 ASSOCIATION object as
   previously described, except as extended by this section.  This
   section applies to ASSOCIATION objects included in both Path and Resv
   messages.

   The following are the modified procedures for Extended ASSOCIATION
   object processing:

   o  When creating an Extended ASSOCIATION object, the originator MUST
      format the object as defined in this document.

   o  The originator MUST set the Association Type, Association ID, and
      Association Source fields as described in Section 4.

   o  When ASN-based global identification of the Association Source is
      desired, the originator MUST set the Global Association Source
      field.  When ASN-based global identification is not desired, the
      originator MUST set the Global Association Source field to zero
      (0).

   o  The Extended ASSOCIATION object originator MAY include the
      Extended Association ID field.  The field is included based on
      local policy.  The field MUST be included when the Association ID
      field is insufficient to uniquely identify association within the
      scope of the source of the association.  When included, this field
      MUST be set to a value that, when taken together with the other
      fields in the object, uniquely identifies the association being
      identified.

   o  The object Length field is set based on the length of the Extended
      Association ID field.  When the Extended Association ID field is
      omitted, the object Length field MUST be set to 16 or 28 for the
      IPv4 and IPv6 ASSOCIATION objects, respectively.  When the
      Extended Association ID field is present, the object Length field
      MUST be set to indicate the additional bytes carried in the
      Extended Association ID field, including pad bytes.



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      Note: Per [RFC2205], the object Length field is set to the total
      object length in bytes, is always a multiple of 4, and is at least
      4.

   The procedures related to association identification are not modified
   by this section.  It is important to note that Section 4 defines the
   identification of associations based on ASSOCIATION object matching
   and that such matching, in the absence of type-specific comparison
   rules, is based on the comparison of all fields in an ASSOCIATION
   object.  This applies equally to ASSOCIATION objects and Extended
   ASSOCIATION objects.

5.  Compatibility

   Per [RFC4872], the ASSOCIATION object uses an object class number of
   the form 11bbbbbb to ensure compatibility with non-supporting nodes.
   Per [RFC2205], such nodes will ignore the object but forward it
   without modification.  This is also the action taken for unknown
   association types as discussed above in Section 3.1.2, 3.2.2, and
   3.3.2.

   Per [RFC4872], transit nodes that support the ASSOCIATION object but
   not the Extended Association C-Types will "transmit, without
   modification, any received ASSOCIATION object in the corresponding
   outgoing Path message".  Per [RFC2205], an egress node that supports
   the ASSOCIATION object but not the Extended Association C-Types, may
   generate an "Unknown object C-Type" error.  This error will propagate
   to the ingress node for standard error processing.

   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.

6.  Security Considerations

   A portion of this document reviews procedures defined in [RFC4872]
   and [RFC4873] and does not define new procedures.  As such, no new
   security considerations are introduced in this portion of the
   document.

   Section 3 defines broader usage of the ASSOCIATION object, but does
   not fundamentally expand on the association function that was
   previously defined in [RFC4872] and [RFC4873].  Section 4 increases
   the number of bits that are carried in an ASSOCIATION object (by 32),
   and similarly does not expand on the association function that was
   previously defined.  This broader definition does allow for
   additional information to be conveyed, but this information is not
   fundamentally different from the information that is already carried



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   in RSVP.  Therefore, there are no new risks or security
   considerations introduced by this document.

   For a general discussion on MPLS- and GMPLS-related security issues,
   including RSVP's chain of trust security model, see the MPLS/GMPLS
   security framework [RFC5920].

7.  IANA Considerations

   IANA has assigned new values for namespaces defined in this document
   and they are summarized in this section.

7.1.  IPv4 and IPv6 Extended ASSOCIATION Objects

   Per this document, IANA has assigned two new C-Types (which are
   defined in Section 3.1) for the existing ASSOCIATION object in the
   "Class Names, Class Numbers, and Class Types" section of the
   "Resource Reservation Protocol (RSVP) Parameters" registry located at
   http://www.iana.org/assignments/rsvp-parameters:

   199  ASSOCIATION                           [RFC4872]

        Class Types or C-Types

           3   Type 3 IPv4 Extended Association   [RFC6780]
           4   Type 4 IPv6 Extended Association   [RFC6780]

7.2.  Resource Sharing Association Type

   This document also broadens the potential usage of the Resource
   Sharing Association Type defined in [RFC4873].  As such, IANA has
   updated the reference of the Resource Sharing Association Type
   included in the associated registry.  Per this document, IANA has
   also corrected the duplicate usage of '(R)' in this registry.  In
   particular, the "Association Type" registry found at
   http://www.iana.org/assignments/gmpls-sig-parameters/ has been
   updated as follows:

      OLD:
        2         Resource Sharing (R)      [RFC4873]

      NEW:
        2         Resource Sharing (S)      [RFC4873][RFC6780]

   There are no other IANA considerations introduced by this document.






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8.  Acknowledgments

   Valuable comments and input were received from Dimitri Papadimitriou,
   Fei Zhang, and Adrian Farrel.  We thank Subha Dhesikan for her
   contribution to the early work on sharing of resources across RSVP
   reservations.

9.  References

9.1.  Normative References

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

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

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

   [RFC4872]  Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
              Ed., "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.

   [RFC5511]  Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
              Used to Form Encoding Rules in Various Routing Protocol
              Specifications", RFC 5511, April 2009.

9.2.  Informative References

   [RFC2207]  Berger, L. and T. O'Malley, "RSVP Extensions for IPSEC
              Data Flows", RFC 2207, September 1997.

   [RFC3175]  Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
              "Aggregation of RSVP for IPv4 and IPv6 Reservations", RFC
              3175, September 2001.




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   [RFC4860]  Le Faucheur, F., Davie, B., Bose, P., Christou, C., and M.
              Davenport, "Generic Aggregate Resource ReSerVation
              Protocol (RSVP) Reservations", RFC 4860, May 2007.

   [RFC5003]  Metz, C., Martini, L., Balus, F., and J. Sugimoto,
              "Attachment Individual Identifier (AII) Types for
              Aggregation", RFC 5003, September 2007.

   [RFC5389]  Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
              "Session Traversal Utilities for NAT (STUN)", RFC 5389,
              October 2008.

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

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

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

Authors' Addresses

   Lou Berger
   LabN Consulting, L.L.C.
   Phone: +1-301-468-9228
   EMail: lberger@labn.net

   Francois Le Faucheur
   Cisco Systems
   Greenside, 400 Avenue de Roumanille
   Sophia Antipolis 06410
   France
   EMail: flefauch@cisco.com

   Ashok Narayanan
   Cisco Systems
   300 Beaver Brook Road
   Boxborough, MA 01719
   United States
   EMail: ashokn@cisco.com










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