path: root/doc/rfc/rfc3474.txt

Network Working Group                                             Z. Lin
Request for Comments: 3474                         New York City Transit
Category: Informational                                    D. Pendarakis
                                                                 Tellium
                                                              March 2003


                 Documentation of IANA assignments for
           Generalized MultiProtocol Label Switching (GMPLS)
     Resource Reservation Protocol - Traffic Engineering (RSVP-TE)
                        Usage and Extensions for
             Automatically Switched Optical Network (ASON)

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   The Generalized MultiProtocol Label Switching (GMPLS) suite of
   protocol specifications has been defined to provide support for
   different technologies as well as different applications.  These
   include support for requesting TDM connections based on Synchronous
   Optical NETwork/Synchronous Digital Hierarchy (SONET/SDH) as well as
   Optical Transport Networks (OTNs).

   This document concentrates on the signaling aspects of the GMPLS
   suite of protocols, specifically GMPLS signaling using Resource
   Reservation Protocol - Traffic Engineering (RSVP-TE).  It proposes
   additional extensions to these signaling protocols to support the
   capabilities of an ASON network.

   This document proposes appropriate extensions towards the resolution
   of additional requirements identified and communicated by the ITU-T
   Study Group 15 in support of ITU's ASON standardization effort.










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Table of Contents

   1. Conventions used in this document...............................3
   2. Introduction....................................................3
   3. Support for Soft Permanent Connection...........................3
   4. Support for Call................................................4
       4.1 Call Identifier and Call Capability........................4
            4.1.1 Call Identifier.....................................4
            4.1.2 Call Capability.....................................7
       4.2 What Does Current GMPLS Provide............................7
       4.3 Support for Call and Connection............................7
            4.3.1 Processing Rules....................................8
            4.3.2 Modification to Path Message........................8
            4.3.3 Modification to Resv Message........................9
            4.3.4 Modification to PathTear Message....................9
            4.3.5 Modification to PathErr Message....................10
            4.3.6 Modification to Notify Message.....................10
   5.  Support For Behaviors during Control Plane Failures...........11
   6.  Support For Label Usage.......................................12
   7.  Support for UNI and E-NNI Signaling Session...................13
   8.  Additional Error Cases........................................14
   9.  Optional Extensions for Supporting
       Complete Separation of Call and Connection....................15
       9.1 Call Capability.........;.................................15
       9.2 Complete Separation of Call and
           Connection (RSVP-TE Extensions)...........................16
            9.2.1 Modification to Path...............................16
            9.2.2 Modification to Resv...............................17
            9.2.3 Modification to PathTear...........................18
            9.2.4 Modification to PathErr............................18
            9.2.5 Modification to Notify.............................18
   10. Security Considerations.......................................19
   11. IANA Considerations...........................................19
       11.1 Assignment of New Messages...............................19
       11.2 Assignment of New Objects and Sub-Objects................19
       11.3 Assignment of New C-Types................................20
       11.4 Assignment of New Error Code/Values......................20
   12. Acknowledgements..............................................20
   13. References....................................................21
       13.1 Normative References.....................................21
       13.2 Informative References...................................22
   14. Intellectual Property.........................................23
   15. Contributors Contact Information..............................24
   16. Authors' Addresses............................................24
   17. Full Copyright Statement......................................25






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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 BCP 14, RFC 2119
   [RFC2119].

2. Introduction

   This document contains the extensions to GMPLS for ASON-compliant
   networks [G7713.2].  The requirements describing the need for these
   extensions are provided in [GMPLS-ASON] as well as [ASON-RQTS].
   These include:

   -    Support for call and connection separation
   -    Support for soft permanent connection
   -    Support for extended restart capabilities
   -    Additional error codes/values to support these extensions

   This document concentrates on the signaling aspects of the GMPLS
   suite of protocols, specifically GMPLS signaling using RSVP-TE.  It
   introduces extensions to GMPLS RSVP-TE to support the capabilities as
   specified in the above referenced documents.  Specifically, this
   document uses the messages and objects defined by [RFC2205],
   [RFC2961], [RFC3209], [RFC3471], [RFC3473], [OIF-UNI1] and [RFC3476]
   as the basis for the GMPLS RSVP-TE protocol, with additional
   extensions defined in this document.

3. Support for Soft Permanent Connection

   In the scope of ASON, to support soft permanent connection (SPC) for
   RSVP-TE, one new sub-type for the GENERALIZED_UNI object is defined.
   The GENERALIZED_UNI object is defined in [RFC3476] and [OIF-UNI1].
   This new sub-type has the same format and structure as the
   EGRESS_LABEL (the sub-type is the suggested value for the new sub-
   object):

   -    SPC_LABEL (Type=4, Sub-type=2)

   The label association of the permanent ingress segment with the
   switched segment at the switched connection ingress node is a local
   policy matter (i.e., between the management system and the switched
   connection ingress node) and is thus beyond the scope of this
   document.







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   The processing of the SPC_LABEL sub-object follows that of the
   EGRESS_LABEL sub-object [OIF-UNI1].  Note that although the explicit
   label control described in [RFC3471] and [RFC3473] may provide a
   mechanism to support specifying the egress label in the context of
   supporting the GMPLS application, the SPC services support for the
   ASON model uses the GENERALIZED_UNI object for this extension to help
   align the model for both switched connection and soft permanent
   connection, as well as to use the service level and diversity
   attributes of the GENERALIZED_UNI object.

4. Support for Call

   To support basic call capability (logical call/connection
   separation), a call identifier is introduced to the RSVP-TE message
   sets.  This basic call capability helps introduce the call model;
   however, additional extensions may be needed to fully support the
   canonical call model (complete call/connection separation).

4.1 Call Identifier and Call Capability

   A Call identifier object is used in logical call/connection
   separation while both the Call identifier object and a Call
   capability object are used in complete call/connection separation.

4.1.1 Call Identifier

   To identify a call, a new object is defined for RSVP-TE.  The CALL_ID
   object carries the call identifier.  The value is globally unique
   (the Class-num is the suggested value for the new object):

   CALL_ID (Class-num = 230)

    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 (230)|    C-Type     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Call identifier                        |
   ~                              ...                              ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Where the following C-types are defined:

   -  C-Type = 1 (operator specific): The call identifier contains an
      operator specific identifier.

   -  C-Type = 2 (globally unique): The call identifier contains a
      globally unique part plus an operator specific identifier.



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   The following structures are defined for the call identifier:

   -  Call identifier: generic [Length*8-32]-bit identifier.  The number
      of bits for a call identifier must be multiples of 32 bits, with a
      minimum size of 32 bits.

   The structure for the globally unique call identifier (to guarantee
   global uniqueness) is to concatenate a globally unique fixed ID
   (composed of country code, carrier code, unique access point code)
   with an operator specific ID (where the operator specific ID is
   composed of a source LSR address and a local identifier).

   Therefore, a generic CALL_ID with global uniqueness includes <global
   ID> (composed of <country code> plus <carrier code> plus <unique
   access point code>) and <operator specific ID> (composed of <source
   LSR address> plus <local identifier>).  For a CALL_ID that only
   requires operator specific uniqueness, only the <operator specific
   ID> is needed, while for a CALL_ID that is required to be globally
   unique, both <global ID> and <operator specific ID> are needed.

   The <global ID> shall consist of a three-character International
   Segment (the <country code>) and a twelve-character National Segment
   (the <carrier code> plus <unique access point code>).  These
   characters shall be coded according to ITU-T Recommendation T.50. The
   International Segment (IS) field provides a 3 character ISO 3166
   Geographic/Political Country Code.  The country code shall be based
   on the three-character uppercase alphabetic ISO 3166 Country Code
   (e.g., USA, FRA).

   National Segment (NS):
      The National Segment (NS) field consists of two sub-fields:

      - the first subfield contains the ITU Carrier Code
      - the second subfield contains a Unique Access Point Code.

   The ITU Carrier Code is a code assigned to a network operator/service
   provider, maintained by the ITU-T Telecommunication Service Bureauin
   association with Recommendation M.1400.  This code consists of 1-6
   left-justified alphabetic, or leading alphabetic followed by numeric,
   characters (bytes).  If the code is less than 6 characters (bytes),
   it is padded with a trailing NULL to fill the subfield.

   The Unique Access Point Code is a matter for the organization to
   which the country code and ITU carrier code have been assigned,
   provided that uniqueness is guaranteed.  This code consists of 1-6
   characters (bytes), trailing NULL, completing the 12-character
   National Segment.  If the code is less than 6 characters, it is
   padded by a trailing NULL to fill the subfield.



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   Format of the National Segment

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       ITU carrier code                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | ITU carrie dode (cont)        |  Unique access point code     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unique access point code (continued)            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The format of the Call identifier field for C-Type = 1:

    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 (230)|  C-Type  (1)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |                     Resv                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Source LSR address                       |
   ~                              ...                              ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Local identifier                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Local identifier  (continued)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+























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   The format of the Call identifier field for C-Type = 2:

    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 (230)|  C-Type  (2)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |               IS (3 bytes)                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                         NS (12 bytes)                         |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Source LSR address                       |
   ~                              ...                              ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Local identifier                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Local identifier  (continued)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   In both cases, a "Type" field is defined to indicate the type of
   format used for the source LSR address.  The Type field has the
   following meaning:
      For Type=0x01, the source LSR address is 4 bytes
      For Type=0x02, the source LSR address is 16 bytes
      For Type=0x03, the source LSR address is 20 bytes
      For type=0x04, the source LSR address is 6 bytes
      For type=0x7f, the source LSR address has the length defined by
          the vendor

      Source LSR address:
            An address of the LSR controlled by the source network.

      Local identifier:
            A 64-bit identifier that remains constant over the life of
            the call.

   Note that if the source LSR address is assigned from an address space
   that is globally unique, then the operator-specific CALL_ID may also
   be used to represent a globally unique CALL_ID.  However, this is not
   guaranteed since the source LSR address may be assigned from an
   operator-specific address space.








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4.1.2 Call Capability

   The call capability feature is provided in Section 10.  This is an
   optional capability.  If supported, section 10 extensions must be
   followed.

4.2 What Does Current GMPLS Provide

   The signaling mechanism defined in [RFC2961], [RFC3209] and [RFC3471]
   supports automatic connection management; however it does not provide
   capability to support the call model.  A call may be viewed as a
   special purpose connection that requires a different subset of
   information to be carried by the messages.  This information is
   targeted to the call controller for the purpose of setting up a
   call/connection association.

4.3 Support for Call and Connection

   Within the context of this document, every call (during steady state)
   may have one (or more) associated connections.  A zero connection
   call is defined as a transient state, e.g., during a break-before-
   make restoration event.

   In the scope of ASON, to support a logical call/connection
   separation, a new call identifier is needed as described above.  The
   new GENERALIZED_UNI object is carried by the Path message.  The new
   CALL_ID object is carried by the Path, Resv, PathTear, PathErr, and
   Notify messages.  The ResvConf message is left unmodified.  The
   CALL_ID object (along with other objects associated with a call,
   e.g., GENERALIZED_UNI) is processed by the call controller, while
   other objects included in these messages are processed by the
   connection controller as described in [RFC3473].  Processing of the
   CALL_ID (and related) object is described in this document.

   Note: unmodified RSVP message formats are not listed below.

4.3.1 Processing Rules

   The following processing rules are applicable for call capability:

   -  For initial calls, the source user MUST set the CALL_ID's C-Type
      and call identifier value to all-zeros.
   -  For a new call request, the first network node sets the
      appropriate C-type and value for the CALL_ID.
   -  For an existing call (in case CALL_ID is non-zero) the first
      network node verifies existence of the call.





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   -  The CALL_ID object on all messages MUST be sent from the ingress
      call controller to egress call controller by all other
      (intermediate) controllers without alteration.  Indeed, the
      Class-Num is chosen such that a node which does not support ASON
      extensions to GMPLS forwards the object unmodified (value in the
      range 11bbbbbb).
   -  The destination user/client receiving the request uses the CALL_ID
      value as a reference to the requested call between the source user
      and itself.  Subsequent actions related to the call uses the
      CALL_ID as the reference identifier.

4.3.2 Modification to Path Message

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

   The format of the sender descriptor for unidirectional LSPs is not
   modified by this document.

   The format of the sender descriptor for bidirectional LSPs is not
   modified by this document.

   Note that although the GENERALIZED_UNI and CALL_ID objects are
   optional for GMPLS signaling, these objects are mandatory for ASON-
   compliant networks, i.e., the Path message MUST include both
   GENERALIZED_UNI and CALL_ID objects.








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4.3.3 Modification to Resv Message

   <Resv Message> ::=       <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        <RSVP_HOP>
        <TIME_VALUES>
        [ <CALL_ID> ]
        [ <RESV_CONFIRM> ]
        <SCOPE>
        [ <NOTIFY_REQUEST> ]
        [ <ADMIN_STATUS> ]
        [ <POLICY_DATA> ... ]
           <STYLE>
           <flow descriptor list>

   <flow descriptor list> is not modified by this document.

   Note that although the CALL_ID object is optional for GMPLS
   signaling, this object is mandatory for ASON-compliant networks,
   i.e., the Resv message MUST include the CALL_ID object.

4.3.4 Modification to PathTear Message

   <PathTear Message> ::= <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        <RSVP_HOP>
        [ <CALL_ID> ]
        [ <sender descriptor> ]

   <sender descriptor> ::= (see earlier definition)

   Note that although the CALL_ID object is optional for GMPLS
   signaling, this object is mandatory for ASON-compliant networks,
   i.e., the PathTear message MUST include the CALL_ID object.









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4.3.5 Modification to PathErr Message

   <PathErr Message> ::=    <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        [ <CALL_ID> ]
        <ERROR_SPEC>
        [ <ACCEPTABLE_LABEL_SET> ]
        [ <POLICY_DATA> ... ]
        <sender descriptor>

   <sender descriptor> ::= (see earlier definition)

   Note that although the CALL_ID object is optional for GMPLS
   signaling, this object is mandatory for ASON-compliant networks,
   i.e., the PathErr message MUST include the CALL_ID object.

4.3.6 Modification to Notify Message

   Note that this message may include sessions belonging to several
   calls.

   <Notify message>            ::= <Common Header>
        [<INTEGRITY>]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <ERROR_SPEC>
        <notify session list>

   <notify session list>       ::=
        [ <notify session list> ]
        <upstream notify session> |
        <downstream notify session>

   <upstream notify session>   ::= <SESSION>
        [ <CALL_ID> ]
        [ <ADMIN_STATUS> ]
        [<POLICY_DATA>...]
        <sender descriptor>

   <downstream notify session> ::= <SESSION>
        [ <CALL_ID> ]
        [<POLICY_DATA>...]
        <flow descriptor list descriptor>



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   Note that although the CALL_ID object is optional for GMPLS
   signaling, this object is mandatory for ASON-compliant networks,
   i.e., the Notify message MUST include the CALL_ID object.

5. Support For Behaviors during Control Plane Failures

   Various types of control plane failures may occur within the network.
   These failures may impact the control plane as well as the data plane
   (e.g., in a SDH/SONET network if the control plane transport uses the
   DCC and a fiber cut occurs, then both the control plane signaling
   channel and the transport plane connection fails).  As described in
   [RFC3473], current GMPLS restart mechanisms allows support to handle
   all of these different scenarios, and thus no additional extensions
   are required.

   In the scope of the ASON model, several procedures may take place in
   order to support the following control plane behaviors (as per
   [G7713] and [IPO-RQTS]):

   -  A control plane node SHOULD provide capability for persistent
      storage of call and connection state information.  This capability
      allows each control plane node to recover the states of
      calls/connections after recovery from a signaling controller
      entity failure/reboot (or loss of local FSM state).  Note that
      although the restart mechanism allows neighbor control plane nodes
      to automatically recover (and thus infer) the states of
      calls/connections, this mechanism can also be used for
      verification of neighbor states, while the persistent storage
      provides the local recovery of lost state.  In this case, per
      [RFC3473], if during the Hello synchronization the restarting node
      determines that a neighbor does not support state recovery (i.e.,
      local state recovery only), and the restarting node maintains its
      state on a per neighbor basis, the restarting node should
      immediately consider the Recovery as completed.
   -  A control plane node detecting a failure of all control channels
      between a pair of nodes SHOULD request an external controller
      (e.g., the management system) for further instructions.  The
      default behavior is to enter into self-refresh mode (i.e.,
      preservation) for the local call/connection states.  As an
      example, possible external instructions may be to remain in self-
      refresh mode, or to release local states for certain connections.
      Specific details are beyond the scope of this document.
   -  A control plane node detecting that one (or more) connections
      cannot be re-synchronized with its neighbor (e.g., due to
      different states for the call/connection) SHOULD request an
      external controller (e.g., the management system) for further
      instructions on how to handle the non-synchronized connection. As
      an example, possible instructions may be to maintain the current



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      local connection states.  Specifics of the interactions between
      the control plane and management plane are beyond the scope of
      this document.
   -  A control plane node (after recovering from node failure) may lose
      information on forwarding adjacencies.  In this case the control
      plane node SHOULD request an external controller (e.g., the
      management system) for information to recover the forwarding
      adjacency information.  Specifics of the interactions between the
      control plane and management plane are beyond the scope of this
      document.

6. Support For Label Usage

   Labels are defined in GMPLS to provide information on the resources
   used for a particular connection.  The labels may range from
   specifying a particular timeslot, or a particular wavelength, to a
   particular port/fiber.  In the context of the automatic switched
   optical network, the value of a label may not be consistently the
   same across a link.  For example, the figure below illustrates the
   case where two GMPLS/ASON-enabled nodes (A and Z) are interconnected
   across two non-GMPLS/ASON-enabled nodes (B and C; i.e., nodes B and C
   do not support the ASON capability), where these nodes are all
   SDH/SONET nodes providing, e.g., a VC-4 service.

   +-----+                   +-----+
   |     |   +---+   +---+   |     |
   |  A  |---| B |---| C |---|  Z  |
   |     |   +---+   +---+   |     |
   +-----+                   +-----+

   Labels have an associated structure imposed on them for local use
   based on [GMPLS-SDHSONET] and [GMPLS-OTN].  Once the local label is
   transmitted across an interface to its neighboring control plane
   node, the structure of the local label may not be significant to the
   neighbor node since the association between the local and the remote
   label may not necessarily be the same.  This issue does not present a
   problem in a simple point-to-point connection between two control
   plane-enabled nodes where the timeslots are mapped 1:1 across the
   interface.  However, in the scope of the ASON, once a non-GMPLS
   capable sub-network is introduced between these nodes (as in the
   above figure, where the sub-network provides re-arrangement
   capability for the timeslots) label scoping may become an issue.

   In this context, there is an implicit assumption that the data plane
   connections between the GMPLS capable edges already exist prior to
   any connection request.  For instance node A's outgoing VC-4's
   timeslot #1 (with SUKLM label=[1,0,0,0,0]) as defined in [GMPLS-
   SONETSDH]) may be mapped onto node B's outgoing VC-4's timeslot #6



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   (label=[6,0,0,0,0]) may be mapped onto node C's outgoing VC-4's
   timeslot #4 (label=[4,0,0,0,0]).  Thus by the time node Z receives
   the request from node A with label=[1,0,0,0,0], the node Z's local
   label and the timeslot no longer corresponds to the received label
   and timeslot information.

   As such to support the general case, the scope of the label value is
   considered local to a control plane node.  A label association
   function can be used by the control plane node to map the received
   (remote) label into a locally significant label.  The information
   necessary to allow mapping from a received label value to a locally
   significant label value may be derived in several ways:

   -    Via manual provisioning of the label association
   -    Via discovery of the label association

   Either method may be used.  In the case of dynamic association, this
   implies that the discovery mechanism operates at the timeslot/label
   level before the connection request is processed at the ingress node.
   Note that in the simple case where two nodes are directly connected,
   no association may be necessary.  In such instances, the label
   association function provides a one-to-one mapping of the received
   local label values.

7. Support for UNI and E-NNI Signaling Session

   [RFC3476] defines a UNI IPv4 SESSION object used to support the UNI
   signaling when IPv4 addressing is used.  This document introduces
   three new extensions.  These extensions specify support for the IPv4
   and IPv6 E-NNI session and IPv6 UNI session.  These C-Types are
   introduced to allow for easier identification of messages as regular
   GMPLS messages, UNI messages, or E-NNI messages.  This is
   particularly useful if a single interface is used to support multiple
   service requests.

   Extensions to SESSION object (Class-num = 1):
   -    C-Type = 12: UNI_IPv6 SESSION object
   -    C-TYPE = 15: ENNI_IPv4 SESSION object
   -    C-Type = 16: ENNI_IPv6 SESSION object

   The format of the SESSION object with C-Type = 15 is the same as that
   for the SESSION object with C-Type = 7.  The format of the SESSION
   object with C-Type = 12 and 16 is the same as that for the SESSION
   object with C-Type = 8.

   The destination address field contains the address of the downstream
   controller processing the message.  For the case of the E-NNI
   signaling interface (where eNNI-U represents the upstream controller



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   and eNNI-D represents the downstream controller) the destination
   address contains the address of eNNI-D.  [OIF-UNI1] and [RFC3476]
   describes the content of the address for UNI_IPv4 SESSION object,
   which is also applicable for UNI_IPv6 SESSION object.

8. Additional Error Cases

   In the scope of ASON, the following additional error cases are
   defined:

   -  Policy control failure: unauthorized source; this error is
      generated when the receiving node determines that a source
      user/client initiated request for service is unauthorized based on
      verification of the request (e.g., not part of a contracted
      service).  This is defined in [RFC3476].
   -  Policy control failure: unauthorized destination; this error is
      generated when the receiving node determines that a destination
      user/client is unauthorized to be connected with a source
      user/client.  This is defined in [RFC3476].
   -  Routing problem: diversity not available; this error is generated
      when a receiving node determines that the requested diversity
      cannot be provided (e.g., due to resource constraints).  This is
      defined in [RFC3476].
   -  Routing problem: service level not available; this error is
      generated when a receiving node determines that the requested
      service level cannot be provided (e.g., due to resource
      constraints).  This is defined in [RFC3476].
   -  Routing problem: invalid/unknown connection ID; this error is
      generated when a receiving node determines that the connection ID
      generated by the upstream node is not valid/unknown (e.g., does
      not meet the uniqueness property).  Connection ID is defined in
      [OIF-UNI1].
   -  Routing problem: no route available toward source; this error is
      generated when a receiving node determines that there is no
      available route towards the source node (e.g., due to
      unavailability of resources).
   -  Routing problem: unacceptable interface ID; this error is
      generated when a receiving node determines that the interface ID
      specified by the upstream node is unacceptable (e.g., due to
      resource contention).
   -  Routing problem: invalid/unknown call ID; this error is generated
      when a receiving node determines that the call ID generated by the
      source user/client is invalid/unknown (e.g., does not meet the
      uniqueness property).
   -  Routing problem: invalid SPC interface ID/label; this error is
      generated when a receiving node determines that the SPC interface
      ID (or label, or both interface ID and label) specified by the
      upstream node is unacceptable (e.g., due to resource contention).



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9. Optional Extensions for Supporting Complete Separation of Call and
   Connection

   This section describes the optional and non-normative capability to
   support complete separation of call and connection.  To support
   complete separation of call and connection, a call capability object
   is introduced.  The capability described in this Appendix is meant to
   be an optional capability within the scope of the ASON specification.
   An implementation of the extensions defined in this document include
   support for complete separation of call and connection, defined in
   this section.

9.1  Call Capability

   A call capability is used to specify the capabilities supported for a
   call.  For RSVP-TE a new CALL_OPS object is defined to be carried by
   the Path, Resv, PathTear, PathErr, and Notify messages.  The CALL_OPS
   object also serves to differentiate the messages to indicate a
   "call-only" call.  In the case for logical separation of call and
   connection, the CALL_OPS object is not needed.

   The CALL_OPS object is defined as follows (the Class-num is the
   suggested value for the new object):

   CALL_OPS (Class-num = 228, C-type = 1)

   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 (228)|  C-Type (1)   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                Reserved                       | Call ops flag |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Two flags are currently defined for the "call ops flag":
        0x01: call without connection
        0x02: synchronizing a call (for restart mechanism)

9.2  Complete Separation of Call and Connection (RSVP-TE Extensions)

   A complete separation of call and connection implies that a call
   (during steady state) may have zero (or more) associated connections.
   A zero connection call is a steady state, e.g., simply setting up the
   user end-point relationship prior to connection setup.  The following
   modified messages are used to set up a call.  Set up of a connection
   uses the messages defined in Section 5 above.





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9.2.1 Modification to Path

   <Path Message> ::=    <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        <RSVP_HOP>
        <TIME_VALUES>
        [ <EXPLICIT_ROUTE> ]
        <LABEL_REQUEST>
        <CALL_OPS>
        <CALL_ID>
        [ <NOTIFY_REQUEST> ]
        [ <ADMIN_STATUS> ]
        <GENERALIZED_UNI>
        [ <POLICY_DATA> ... ]
        <sender descriptor>

   The format of the sender descriptor for unidirectional LSPs is:

   <sender descriptor> ::=  <SENDER_TEMPLATE>
        <SENDER_TSPEC>
        [ <RECORD_ROUTE> ]

   The format of the sender descriptor for bidirectional LSPs is:

   <sender descriptor> ::=  <SENDER_TEMPLATE>
        <SENDER_TSPEC>
        [ <RECORD_ROUTE> ]
        <UPSTREAM_LABEL>

   Note that LABEL_REQUEST, SENDER_TSPEC and UPSTREAM_LABEL are not
   required for a call; however these are mandatory objects.  As such,
   for backwards compatibility purposes, processing of these objects for
   a call follows the following rules:

   -  These objects are ignored upon receipt; however, a valid-formatted
      object (e.g., by using the received valid object in the
      transmitted message) must be included in the generated message.










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9.2.2 Modification to Resv

   <Resv Message> ::=       <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        <RSVP_HOP>
        <TIME_VALUES>
        <CALL_OPS>
        <CALL_ID>
        [ <RESV_CONFIRM> ]
        [ <NOTIFY_REQUEST> ]
        [ <ADMIN_STATUS> ]
        [ <POLICY_DATA> ... ]
        <STYLE>
        <flow descriptor list>

   <flow descriptor list> ::=
        <FF flow descriptor list>
                | <SE flow descriptor>

   <FF flow descriptor list> ::=
        <FLOWSPEC>
        <FILTER_SPEC>
        [ <RECORD_ROUTE> ]
        | <FF flow descriptor list>
        <FF flow descriptor>
   <FF flow descriptor> ::=
        [ <FLOWSPEC> ]
        <FILTER_SPEC>
        [ <RECORD_ROUTE> ]

   <SE flow descriptor> ::=
        <FLOWSPEC>
        <SE filter spec list>
   <SE filter spec list> ::=
        <SE filter spec>
        | <SE filter spec list>
        <SE filter spec>
   <SE filter spec> ::=
        <FILTER_SPEC>
        [ <RECORD_ROUTE> ]







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   Note that FILTER_SPEC and LABEL are not required for a call; however
   these are mandatory objects.  As such, for backwards compatibility
   purposes, processing of these objects for a call follows the
   following rules:

   -  These objects are ignored upon receipt; however, a valid-formatted
      object (e.g., by using the received valid object in the
      transmitted message) must be included in the generated message.

9.2.3 Modification to PathTear

   <PathTear Message> ::= <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        <RSVP_HOP>
        <CALL_OPS>
        <CALL_ID>
        [ <sender descriptor> ]

   <sender descriptor> ::= (see earlier definition in this section)

9.2.4 Modification to PathErr

   <PathErr Message> ::=    <Common Header>
        [ <INTEGRITY> ]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <SESSION>
        <CALL_OPS>
        <CALL_ID>
        <ERROR_SPEC>
        [ <POLICY_DATA> ... ]
        <sender descriptor>
   <sender descriptor> ::= (see earlier definition in this section)













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9.2.5 Modification to Notify

   <Notify message>            ::= <Common Header>
        [<INTEGRITY>]
        [ [<MESSAGE_ID_ACK> |
                <MESSAGE_ID_NACK>] ... ]
        [ <MESSAGE_ID> ]
        <ERROR_SPEC>
        <notify session list>

   <notify session list>       ::=
        [ <notify session list> ]
        <upstream notify session> |
        <downstream notify session>

   <upstream notify session>   ::= <SESSION>
        <CALL_ID>
        [ <ADMIN_STATUS> ]
        [<POLICY_DATA>...]
        <sender descriptor>

   <downstream notify session> ::= <SESSION>
        <CALL_ID>
        [<POLICY_DATA>...]
        <flow descriptor list descriptor>

10. Security Considerations

   This document introduces no new security considerations.

11. IANA Considerations

   There are multiple fields and values defined within this document.
   IANA administers the assignment of these class numbers in the FCFS
   space as shown in [see: http://www.iana.org/assignments/rsvp-
   parameters].

11.1 Assignment of New Messages

   No new messages are defined to support the functions discussed in
   this document.










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11.2 Assignment of New Objects and Sub-Objects

   Two new objects are defined:

   -  CALL_ID (ASON); this object should be assigned an object
      identifier of the form 11bbbbbb. A suggested value is 230. Two C-
      types are defined for this object
   -  C-Type = 1: Operator specific
   -  C-Type = 2: Globally unique

   For the Type field, there is no range restriction, and the entire
   range 0x00 to 0xff is open for assignment, with 0x00 to 0x7f
   assignment based on FCFS and 0x80 to 0xff assignment reserved for
   Private Use.  The assignments are defined in this document:

   -  Type = 0x01: Source LSR address is 4-bytes
   -  Type = 0x02: Source LSR address is 16-bytes
   -  Type = 0x03: Source LSR address is 20-bytes
   -  Type = 0x04: Source LSR address is 6-bytes
   -  Type = 0x7f: the source LSR address has the length defined by the
      vendor
   -  CALL_OPS (ASON); this object should be assigned an object
      identifier of the form 11bbbbbb.  The value is 228. One C-type is
      defined for this object; the value is 1.

   One new sub-object is defined under the GENERALIZED_UNI object:

   -  SPC_LABEL; this sub-object is part of the GENERALIZED_UNI object,
      as a sub-type of the EGRESS_LABEL sub-object (which is Type=4).
      The value is sub-type=2.

11.3 Assignment of New C-Types

   Three new C-Types are defined for the SESSION object (Class-num = 1):

   -    C-Type = 12 (ASON): UNI_IPv6 SESSION object
   -    C-Type = 15 (ASON): ENNI_IPv4 SESSION object
   -    C-Type = 16 (ASON): ENNI_IPv6 SESSION object

11.4 Assignment of New Error Code/Values

   No new error codes are required.  The following new error values are
   defined.  Error code 24 is defined in [RFC3209].

   24/103 (ASON): No route available toward source
   24/104 (ASON): Unacceptable interface ID
   24/105 (ASON): Invalid/unknown call ID
   24/106 (ASON): Invalid SPC interface ID/label



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12. Acknowledgements

   The authors would like to thank Osama Aboul-Magd, Jerry Ash, Sergio
   Belotti, Greg Bernstein, Adrian Farrel, Nic Larkin, Lyndon Ong,
   Dimitri Papadimitriou, Bala Rajagopalan, and Yangguang Xu for their
   comments and contributions to the document.

13. References

13.1 Normative References

   [G8080]          ITU-T Rec. G.8080/Y.1304, Architecture for the
                    Automatically Switched Optical Network (ASON),
                    November 2001.

   [G7713]          ITU-T Rec. G.7713/Y.1704, Distributed Call and
                    Connection Management (DCM), November 2001.

   [G7713.2]        DCM Signalling Mechanisms Using GMPLS RSVP-TE, ITU-T
                    G.7713.2, January 2003.

   [OIF-UNI1]       UNI 1.0 Signaling Specification, The Optical
                    Internetworking Forum,
                    http://www.oiforum.com/public/UNI_1.0_ia.html

   [RFC2026]        Bradner, S., "The Internet Standards Process --
                    Revision 3", BCP 9, RFC 2026, October 1996.

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

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

   [RFC2961]        Berger, L., Gan, D., Swallow, G., Pan, P., Tommasi,
                    F. and S. Molendini, "RSVP Refresh Overhead
                    Reduction Extensions", RFC 2961, April 2001.

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

   [RFC3471]        Berger, L., Editor, "Generalized Multi-Protocol
                    Label Switching (MPLS) - Signaling  Functional
                    Description", RFC 3471, January 2003.




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

   [RFC3476]        Rajagopalan, R., "Label Distribution Protocol (LDP)
                    and Resource ReserVation Protocol (RSVP) Extensions
                    for Optical UNI Signaling", RFC 3476, March 2003.

   [ITU-LIAISE]     http://www.ietf.org/IESG/LIAISON/ITU-OIF.html

13.2 Informative References

   [G807]           ITU-T Rec. G.807/Y.1301, Requirements For Automatic
                    Switched Transport Networks (ASTN), July 2001

   [IPO-RQTS]       Aboul-Magd, O., "Automatic Switched Optical Network
                    (ASON) Architecture and Its Related Protocols", Work
                    in Progress.

   [GMPLS-ASON]     Lin, Z., "Requirements for Generalized MPLS (GMPLS)
                    Usage and Extensions For Automatically Switched
                    Optical Network (ASON)", Work in Progress.

   [ASON-RQTS]      Xue, Y., "Carrier Optical Services Requirements",
                    Work in Progress.

   [GMPLS-SDHSONET] Mannie, E., "GMPLS Extensions for SONET and SDH
                    Control", Work in Progress.

14. Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights.  Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in RFC 2028.  Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.






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   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard.  Please address the information to the IETF Executive
   Director.

15. Contributors Contact Information

   Sergio Belotti
   Alcatel
   Via Trento 30,
   I-20059 Vimercate, Italy
   EMail: sergio.belotti@netit.alcatel.it

   Nic Larkin
   Data Connection
   100 Church Street,
   Enfield
   Middlesex EN2 6BQ, UK
   EMail: npl@dataconnection.com

   Dimitri Papadimitriou
   Alcatel
   Francis Wellesplein 1,
   B-2018 Antwerpen, Belgium
   EMail: Dimitri.Papadimitriou@alcatel.be

   Yangguang Xu
   Lucent
   1600 Osgood St, Room 21-2A41
   North Andover, MA  01845-1043
   EMail: xuyg@lucent.com

16. Authors' Addresses

   Zhi-Wei Lin
   New York City Transit
   2 Broadway, Room C3.25
   New York, NY 10004

   EMail: zhiwlin@nyct.com

   Dimitrios Pendarakis
   Tellium
   2 Crescent Place
   Oceanport, NJ 07757-0901

   EMail: dpendarakis@tellium.com



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17.  Full Copyright Statement

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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