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Network Working Group                                   Muneyoshi Suzuki
INTERNET DRAFT                                                       NTT
Expires May 19, 1998                                   November 19, 1997


    The Assignment of the Information Field and Protocol Identifier
   in the Q.2941 Generic Identifier and Q.2957 User-to-user Signaling
                       for the Internet Protocol
                <draft-suzuki-git-uus-assignment-00.txt>

Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
   and its working groups.  Note that other groups may also distribute
   working documents as Internet-Drafts.

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

   To learn the current status of any Internet-Draft, please check the
   "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
   Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
   munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
   ftp.isi.edu (US West Coast).


Abstract

   The purpose of this document is to specify the assignment of the
   information field and protocol identifier in the Q.2941 Generic
   Identifier and Q.2957 User-to-user Signaling for the Internet
   protocol.

   The assignment, that is specified in section 4 of this document, is
   designed for advanced B-ISDN signaling support of the Internet
   protocol, especially the B-ISDN signaling support for the connection
   that corresponds to the session in the Internet protocol which is
   clarified in section 2.  This specification provides an indispensable
   framework for the implementation of long-live session and QoS-
   sensitive session transfers over ATM.








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0. Background

   In the ITU-T SG11 meeting held in September 1997 in Geneva, SG11 WP1,
   which has responsibility for the B-ISDN signaling protocol
   recommendation, agreed to establish liaison with the IETF, ATM Forum,
   and other ITU-T Study Groups to provide B-ISDN signaling support for
   the Internet Protocol.

   ITU-T SG11 WP1 will identify Internet services that can be supported
   by the existing B-ISDN signaling protocol framework, and discuss
   protocol modifications based on this identification.  They planned to
   complete this identification until 3Q 1998.  ITU-T SG11 WP1 will also
   identify Internet services that can be supported by enhancements to
   the current B-ISDN signaling protocol capabilities, and discuss new
   protocol based on this identification.  They planned to complete this
   identification until 1Q 1999.  The issues of B-ISDN support for the
   Internet protocol that are currently recognized by SG11 WP1 are
   described in [15].

   The purpose of this document is to specify the assignment of the
   information field and protocol identifier in the Q.2941 Generic
   Identifier and Q.2957 User-to-user Signaling for the Internet
   protocol.  To enable this specification, section 5 of this document
   clarifies amendments to the current B-ISDN signaling protocol.  ITU-T
   SG11 WP1 will modify the current B-ISDN signaling protocol based on
   this clarification.

   Note that the assignment rule described in this document may be
   subject to change, so it should not be implemented until ITU-T SG11
   WP1 decides to modify the B-ISDN signaling protocol based on this
   request.


1. Purpose of Document

   The purpose of this document is to specify the assignment of the
   information field and protocol identifier in the Q.2941 Generic
   Identifier and Q.2957 User-to-user Signaling for the Internet
   protocol.

   The assignment, that is specified in section 4 of this document, is
   designed for advanced B-ISDN signaling support of the Internet
   protocol, especially the B-ISDN signaling support for the connection
   that corresponds to the session in the Internet protocol which is
   clarified in section 2.  Needless to say, the purpose of this
   specification is not limited to this support, and it is also feasible
   for other purposes.




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   This specification provides an indispensable framework for the
   implementation of long-live session and QoS-sensitive session
   transfers over ATM.  Note that this document only specifies the
   assignment of the information field and protocol identifier, and that
   it may not specify complete protocol that enables interoperable
   implementation.  This is because it is beyond the scope of this
   document and will be specified in a separate document.


2. Session-related ATM Connection

   With the development of new multimedia applications on the current
   Internet, the demands for multimedia support are increasing in the IP
   network, which currently supports best effort communications.  In
   particular, demands to support QoS guaranteed communications are
   increasing with the development of voice, audio, and video
   communications applications.  And it may also be necessary to
   introduce the mechanism that can efficiently transfer the huge volume
   of traffic expected with these applications.

   The major features of B-ISDN are high speed, logical multiplexing
   with the VP/VC, and flexible QoS management per VC, so it is quite
   natural to use these distinctive functions of B-ISDN to implement a
   multimedia support mechanism in the IP network.  The flexible QoS
   management and logical multiplexing functions in B-ISDN are the
   expected method of implementing the QoS guaranteed communications in
   the Internet.  And when a long-live session is supported by a
   particular VC, efficient packet forwarding may be possible using the
   high speed and logical multiplexing of B-ISDN.

   This section clarifies B-ISDN signaling functions that are required
   when the session is supported by the VC, for advanced B-ISDN
   signaling support of the Internet protocol.


2.1 Long-live Session Signaling

   An example scenario for establishing a VC for a long-live session is
   shown in Fig. 2.1.












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            IP Router      ATM SW         ATM SW       IP Router
   +----+                        Default VC                        +----+
   | WS |   +------+  UNI  +-----+        +-----+  UNI  +------+   | WS |
   +--+-+   |   /->|<------+-\-/-+--------+-\-/-+------>|<-\   |   +-+--+
      |.....|__/   |===||==|  X  |========|  X  |==||===|   \__|.....|
            |      |       | / \ |        | / \ |       |      |
            +------+       +-----+        +-----+       +------+

            A. New session initially forwarded over a default VC.


            IP Router      ATM SW         ATM SW       IP Router
   +----+                        Default VC                        +----+
   | WS |   +------+  UNI  +-----+        +-----+  UNI  +------+   | WS |
   +--+-+   |   /->|<------+-\-/-+--------+-\-/-+------>|<-\   |   +-+--+
      |.....|__/   |===||==|  X  |========|  X  |==||===|   \__|.....|
            |      |<------+-/-\-+--------+-/-\-+------>|      |
            +------+       +-----+        +-----+       +------+
                               New VC is set up

                 B. New VC is set up for the long-live session.


            IP Router      ATM SW         ATM SW       IP Router
   +----+                        Default VC                        +----+
   | WS |   +------+  UNI  +-----+        +-----+  UNI  +------+   | WS |
   +--+-+   |      |<------+-\-/-+--------+-\-/-+------>|      |   +-+--+
      |.....|__    |===||==|  X  |========|  X  |==||===|    __|.....|
            |  \-->|<------+-/-\-+--------+-/-\-+------>|<--/  |
            +------+       +-----+        +-----+       +------+
                                   New VC

              C. Transfer of the long-live session to a new VC.

   Fig. 2.1: Example scenario for establishing a VC for a long-live session.

   First, a session is multiplexed into the default VC connecting the
   routers.  Then, if a router detects that it is a long-live session,
   it sets up a new VC for the session.  If the new VC is established
   successfully, the long-live session is moved to the new VC.

   In this procedure involving an ATM VC setup, the B-ISDN signaling
   entity in the called side router must detect that the incoming call
   corresponds to a session of the Internet protocol and notify that
   fact to the IP layer entity.  Based on this information, the IP layer
   entity moves the session to the new VC.





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   Therefore, to implement this signaling procedure, the B-ISDN
   signaling must include an session identifier as an information
   element.  The B-LLI, B-HLI, User-user, and Generic Identifier
   information elements are all capable of transferring this
   information.  Considering the original purposes of these information
   elements, the most appropriate one to use is the Generic Identifier
   information element.


2.2 QoS-sensitive Session Signaling

   The major difference between QoS-sensitive session signaling and
   long-live session signaling is that call setup is not initiated by
   the detection of a long-live session, but is explicitly initiated by
   the setup protocol such as ST2+ and RSVP.  To implement QoS-sensitive
   session signaling using ATM, the ATM network between the routers must
   forward not only the session identifier but also the setup protocol.

   There are two schemes for forwarding the setup protocol.  One is to
   multiplex the protocol into a default VC connecting the routers, or
   to forward the protocol through a particular VC.  In this case, the
   QoS-sensitive session and the ATM VC are established sequentially.
   The second scheme is to forward the setup protocol as an information
   element in the B-ISDN signaling.  In this case, the QoS-sensitive
   session and the ATM VC are established simultaneously.  The latter
   scheme has the following advantages compared with the former one.

   o Easier to implement.

     - Admission control is simplified, because admission control for
       the IP and ATM layers can be done simultaneously.

     - Watchdog timer processing is simplified, because there is no need
       to watch the IP layer establishment and ATM layer establishment
       sequentially.

   o If the setup protocol supports negotiation, then an ATM VC whose
     QoS is based on the result of negotiation can be established.

   However, the latter scheme, at least, cannot support a case where a
   PVC is used to support a QoS-sensitive session.  Therefore, both
   procedures should be taken into account.

   An example of a message sequence that simultaneously establishes a
   QoS-sensitive session and an ATM VC is shown in Fig. 2.2.






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            IP Router      ATM SW         ATM SW       IP Router
   +----+                        Default VC                        +----+
   | WS |   +------+  UNI  +-----+ Setup  +-----+  UNI  +------+   | WS |
   +--+-+   |   /->|<------+-\-/--Protocol--\-/-+------>|<-\   |   +-+--+
      |.....|__/   |===||==|  X  |========|  X  |==||===|   \__|.....|
            |  \-->|<------+-/-\-+--------+-/-\-+------>|<--/  |
            +------+       +-----+  Data  +-----+       +------+
                                   QoS VC
    N-CONNECT |                                              |
   ---------->|  |             |            |             |  |
              |->|    SETUP    |            |             |  |
              |  |------------>|            |             |  |
              |  |<------------|            |             |  |
              |  |  CALL PROC  |----------->|    SETUP    |  |
              |  |             |            |------------>|  |
              |  |             |            |             |->| N-CONNECT
              |  |             |            |             |  |---------->
              |  |             |            |             |  |<----------
              |  |             |            |    CONN     |<-| N-CONNECT-ACK
              |  |             |            |<------------|  |
              |  |             |            |------------>|  |
              |  |    CONN     |<-----------|  CONN ACK   |->|
              |  |<------------|            |             |  |
              |  |------------>|            |             |  |
              |<-|  CONN ACK   |            |             |  |
   <----------|  |             |            |             |  |
    N-CONNECT |                                              |
         -ACK

   Fig. 2.2: Example procedure for simultaneous QoS-sensitive session and
             ATM VC establishment.

   Both ST2+ and RSVP are currently proposed for the setup protocol and
   new setup protocols are likely to be developed in the near future.
   Therefore, to generalize the discussion, the procedure for the setup
   protocol in this example is the general connection setup procedure
   using confirmed service.

   To implement this signaling procedure, the B-ISDN signaling must
   include the User-user information element that the capacity is
   sufficient to forward the setup protocol.










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3. Overview of the Generic Identifier and User-to-user Signaling

3.1 Overview of the Generic Identifier

   The Generic Identifier enables the transfer of identifiers between
   end-to-end users in the ATM network, and it is defined in the Q.2941
   as an optional information element for the Q.2931 and Q.2971 UNI
   signaling protocol.  The SETUP, ALERTING, CONNECT, RELEASE, RELEASE
   COMPLETE, ADD PARTY, PARTY ALERTING, ADD PARTY ACK, ADD PARTY REJECT,
   DROP PARTY, and DROP PARTY ACK messages that are transferred between
   end-to-end users in the ATM network may contain up to three Generic
   Identifier information elements.  The ATM network transfers the
   Generic Identifier information element transparently if it contains
   no coding rule errors.

   Currently ITU-T SG11 recommends the Q.2941 Part 1 (Q.2941.1) that
   supports the transfer of identifiers for the DSM-CC and H.310.  Note
   that the Generic Identifier for the Internet protocol will be
   recommended in a new part of the Q.2941 (e.g. Q.2941.2 or Q.2941.3).

   The format of the Generic Identifier information element specified in
   the Q.2941.1 is shown in Fig. 3.1.





























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                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = Generic identifier transport IE (0x7F)   |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |    Identifier related standard/application    |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |  6
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |  7
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier value               |  8
           =                                               =
           +-----+-----+-----+-----+-----+-----+-----+-----+
           =                                               =
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |  N
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |  N+1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier value               |  N+2
           =                                               =
           +-----+-----+-----+-----+-----+-----+-----+-----+

      Fig. 3.1: Format of the Generic Identifier information element.

   The usage of the first 4 octets of fields is specified in section 4
   of the Q.2931.

   The Identifier related standard/application field identifies the
   standard or application that uses the identifier.

   A transferred identifier is given by the combination of the
   Identifier type, length and value fields, and a Generic Identifier
   information element may contain multiple identifiers.

   The Identifier type field is currently specified for the Session or
   Resource.







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   The maximum length of the Generic Identifier information element is
   currently 33 octets.

   See the Q.2941.1 for detailed protocol specifications of the Generic
   Identifier.


3.2 Overview of the User-to-user Signaling

   The User-to-user Signaling enables the transfer of information
   between end-to-end users in the ATM network, and it is defined in
   Q.2957 and in Q.2971 annex D as an optional information element for
   the Q.2931 and Q.2971 UNI signaling protocol.  The SETUP, ALERTING,
   CONNECT, RELEASE, RELEASE COMPLETE, PROGRESS, ADD PARTY, PARTY
   ALERTING, ADD PARTY ACK, ADD PARTY REJECT, DROP PARTY, and DROP PARTY
   ACK messages that are transferred between end-to-end users in the ATM
   network may contain a User-user information element.  The ATM network
   transfers the User-user information element transparently if it
   contains no coding rule errors.

   From the viewpoint of B-ISDN signaling applications, it seems the
   Generic Identifier and User-to-user Signaling are similar functions.
   But their rules for processing exceptions are not completely the
   same, because their purposes are different. Another difference is
   that the latter supports interworking with the user-user information
   element in the Q.931 N-ISDN signaling, but the Generic Identifier
   does not.

   The format of the User-user information element is shown in Fig. 3.2.






















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                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = User-user information element (0x7E)     |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |             Protocol discriminator            |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               User information                |  6
           =                                               =
           |                                               |
           +-----+-----+-----+-----+-----+-----+-----+-----+

          Fig. 3.2: Format of the User-user information element.

   The usage of the first 4 octets of fields is specified in section 4
   of the Q.2931.

   The Protocol discriminator field identifies the upper layer protocol
   that uses the user-user information.

   The User information field contains the user-user information to be
   transferred.

   The maximum length of the User-user information element is currently
   133 octets.

   See Q.2957 and Q.2971 annex D for detailed protocol specifications of
   the User-to-user Signaling.

















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4. Information Field and Protocol Identifier Assignment

4.1 Assignment in the Generic Identifier Information Element

4.1.1 Principle of assignment

   The information field and protocol identifier assignment principle
   for the Internet protocol in the Generic Identifier information
   element is shown in Fig. 4.1.

                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = Generic identifier transport IE (0x7F)   |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |    Identifier related standard/application    |
           |     = Internet protocol/application (TBD)     |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |  6
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |  7
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier value               |  8
           =                                               =
           +-----+-----+-----+-----+-----+-----+-----+-----+
           =                                               =
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |  N
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |  N+1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier value               |  N+2
           =                                               =
           +-----+-----+-----+-----+-----+-----+-----+-----+

        Fig. 4.1: Principle of assignment in the Generic Identifier
                  information element.

   The Identifier related standard/application field is the Internet
   protocol/application (TBD).





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   Assignment of the Identifier type field is as follows.

     0x00: Reserved.

     0x01: IPv4 session identifier.

     0x02: ST2+ session identifier.

     0x03: IPv6 session identifier.

     0x04-0xFD: Reserved for IANA assignment.

     0xFE: Experiment/Vendor specific.

     0xFF: Reserved.

   The Identifier value field is assigned to Internet
   protocol/application related information that is identified by the
   Identifier type field.

   If the Experiment/Vendor specific is specified in the Identifier type
   field, the first 3 octets in the Identifier value field must contain
   the Organizationally unique identifier (OUI).




























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4.1.2 IPv4 session identifier

   The format of the IPv4 session identifier is shown in Fig. 4.2.

                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = Generic identifier transport IE (0x7F)   |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |
           |             = 16 octets (0x00-10)             |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |    Identifier related standard/application    |
           |     = Internet protocol/application (TBD)     |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |
           |        = IPv4 session identifier (0x01)       |  6
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |
           |               = 13 octets (0x0D)              |  7
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |              Source IPv4 address              |  8-11
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |           Destination IPv4 address            |  12-15
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                   Protocol                    |  16
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                  Source Port                  |  17-18
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Destination Port               |  19-20
           +-----+-----+-----+-----+-----+-----+-----+-----+

                    Fig. 4.2: IPv4 session identifier.

   The Identifier type field is the IPv4 session identifier (0x01).

   The Source IPv4 address, Destination IPv4 address, Protocol, Source
   Port, and Destination Port [5, 7, 8] are assigned in that order to
   the Identifier value field.

   The Length of contents of information element and Identifier length
   are 16 and 13 octets respectively.





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4.1.3 ST2+ session identifier

   The format of the ST2+ session identifier is shown in Fig. 4.3.

                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = Generic identifier transport IE (0x7F)   |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |
           |             = 9 octets (0x00-09)              |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |    Identifier related standard/application    |
           |     = Internet protocol/application (TBD)     |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |
           |        = ST2+ session identifier (0x02)       |  6
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |
           |               = 6 octets (0x06)               |  7
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Stream ID (SID)                |  8-13
           +-----+-----+-----+-----+-----+-----+-----+-----+

                    Fig. 4.3: ST2+ session identifier.

   The Identifier type field is the ST2+ session identifier (0x02).

   The Stream ID (SID) [9] is assigned to the Identifier value field.

   The Length of contents of information element and Identifier length
   are 9 and 6 octets respectively.















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4.1.4 IPv6 session identifier

   The format of the IPv6 session identifier is shown in Fig. 4.4.

                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = Generic identifier transport IE (0x7F)   |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |
           |             = 40 octets (0x00-28)             |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |    Identifier related standard/application    |
           |     = Internet protocol/application (TBD)     |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Identifier type                |
           |        = IPv6 session identifier (0x03)       |  6
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |               Identifier length               |
           |               = 37 octets (0x25)              |  7
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |              Source IPv6 address              |  8-23
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |           Destination IPv6 address            |  24-39
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                   Protocol                    |  40
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                  Source Port                  |  41-42
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |                Destination Port               |  43-44
           +-----+-----+-----+-----+-----+-----+-----+-----+

                     Fig. 4.4: IPv6 session identifier

   The Identifier type field is the IPv6 session identifier (0x03).

   The Source IPv6 address, Destination IPv6 address, Protocol, Source
   Port, and Destination Port [6, 7, 8] are assigned in that order to
   the Identifier value field.

   The Length of contents of information element and Identifier length
   are 40 and 37 octets respectively.





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4.2 Assignment in the User-user Information Element

4.2.1 Principle of assignment

   The information field and protocol identifier assignment principle
   for the Internet protocol in the User-user information element is
   shown in Fig. 4.5.

                                 Bits
              8     7     6     5     4     3     2     1    Octets
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |        Information element identifier         |
           |    = User-user information element (0x7E)     |  1
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |  1  |   Coding  |    IE instruction field     |
           | Ext |  standard |Flag |Res. |  IE action ind. |  2
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Length of contents of information element   |  3-4
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |             Protocol discriminator            |
           |     = Internet protocol/application (TBD)     |  5
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |    Internet protocol/application identifier   |  6
           +-----+-----+-----+-----+-----+-----+-----+-----+
           |   Internet protocol/application related info. |  7-
           =                                               =
           |                                               |
           +-----+-----+-----+-----+-----+-----+-----+-----+

   Fig. 4.5: Principle of assignment in the User-user information element.

   The Protocol discriminator field is the Internet protocol/application
   (TBD).  In this case, the first 1 octet in the User information field
   is the Internet protocol/application identifier field.

   Assignment of the Internet protocol/application identifier field is
   as follows.

     0x00: Reserved.

     0x01-0xFD: Reserved for IANA assignment (Note).

     0xFE: Experiment/Vendor specific.

     0xFF: Reserved.






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   Note: Assignment of the Internet protocol/application identifier
   field for the setup protocol will be specified in a separate
   document.

   The field that follows the Internet protocol/application identifier
   field is assigned to Internet protocol/application related
   information that is identified by the Internet protocol/application
   identifier field.

   If the Experiment/Vendor specific is specified in the Internet
   protocol/application identifier field, the first 3 octets in the
   Internet protocol/application related information field must contain
   the Organizationally unique identifier (OUI).


5. Required Amendments to B-ISDN Signaling

   The information field and protocol identifier assignment in the
   Generic Identifier information element and User-user information
   element, which are described in the previous section, are required
   for advanced B-ISDN signaling support of the Internet protocol.  To
   enable this support, this section clarifies amendments to the B-ISDN
   signaling.


5.1 Required Amendments to the Generic Identifier

   To enable advanced B-ISDN signaling support for the Internet
   protocol, the following amendments should be applied to the Q.2941.1
   Generic Identifier.

   o Increase the maximum length of the Generic Identifier information
     element to at least 44 octets.

   o Add the Internet protocol/application to the Identifier related
     standard/application.


5.2 Required Amendments to the User-to-user Signaling

   To enable advanced B-ISDN signaling support for the Internet
   protocol, the following amendments should be applied to the Q.2957
   and Q.2971 annex D User-to-user Signaling.

   o Increase the maximum length of the User-user information element to
     sufficiently long, that is at least 262 octets, to forward the
     setup protocol.




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   o Add the Internet protocol/application to the Protocol
     discriminator.


6. Security Considerations

   This document specifies the information field and protocol identifier
   assignment in the Q.2941 Generic Identifier and Q.2957 User-to-user
   Signaling for the Internet protocol, so these do not weaken the
   security of the B-ISDN signaling.

   In a called party of the B-ISDN signaling, if the incoming SETUP
   message contains the calling party number and if it is verified and
   passed by the ATM network or it is provided by the network, then it
   is feasible to use the calling party number for part of the calling
   party authentication to strengthen security.


References

      [1] ITU-T, "Broadband Integrated Services Digital Network (B-
      ISDN)-Digital Subscriber Signaling System No. 2 (DSS 2)-User-
      Network Interface (UNI) Layer 3 Specification for Basic
      Call/Connection Control," ITU-T Recommendation Q.2931, September
      1995.

      [2] ITU-T, "Broadband Integrated Services Digital Network (B-
      ISDN)-Digital Subscriber Signaling System No. 2 (DSS 2)-User-
      Network Interface Layer 3 Specification for Point-to-Multipoint
      Call/Connection Control," ITU-T Recommendation Q.2971, October
      1995.

      [3] ITU-T, "Broadband Integrated Services Digital Network (B-ISDN)
      Digital Subscriber Signaling System No. 2 (DSS 2): Generic
      Identifier Transport," Draft ITU-T New Recommendation Q.2941.1,
      September 1997.

      [4] ITU-T, "Stage 3 Description for Additional Information
      Transfer Supplementary Service Using B-ISDN Digital Subscriber
      Signaling System No. 2 (DSS 2)- Basic Call Clause 1-User-to-User
      Signalling (UUS)," ITU-T Recommendation Q.2957, February 1995.

      [5] J. Postel Ed., "Internet Protocol," RFC 791, September 1981.

      [6] S. Deering and R. Hinden, "Internet Protocol, Version 6 (IPv6)
      Specification," Internet Draft, July 1997, <draft-ietf-ipngwg-
      ipv6-spec-v2-00.txt>.




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      [7] J. Postel, "User Datagram Protocol," RFC 768, August 1980.

      [8] J. Postel Ed., "Transmission Control Protocol," RFC 793,
      September 1981.

      [9] L. Delgrossi and L. Berger, Ed., "Internet Stream Protocol
      Version 2 (ST2) Protocol Specification - Version ST2+," RFC 1819,
      August 1995.

      [10] R. Braden Ed., "Resource ReSerVation Protocol (RSVP)-Version
      1 Functional Specification," RFC 2205, September 1997.

      [11] P. Newman, T. Lyon, and G. Minshall, "Flow Labelled IP: A
      Connectionless Approach to ATM," Proc. IEEE Infocom, March 1996.

      [12] S. Damaskos and A. Gavras, "Connection Oriented Protocols
      over ATM: A case study," Proc. SPIE, Vol. 2188, pp.226-278,
      February 1994.

      [13] ITU-T, "Integrated Services Digital Network (ISDN) Overall
      Network Aspects and Functions ISDN Protocol Reference Model,"
      ITU-T Recommendation I.320, November 1993.

      [14] ITU-T, "Digital Subscriber Signaling System No. 1 (DSS 1)
      Specification of a Synchronization and Coordination Function for
      the Provision of the OSI Connection-mode Network Service in an
      ISDN Environment," ITU-T Recommendation Q.923, February 1995.

      [15] K. Kitami, "Expected Direction for B-ISDN & Multimedia
      Signaling in the Areas for Enhancements, focusing on the support
      of the Internet," ITU-T SG11 Delayed Contribution D.398, September
      1997, (http://www.nal.ecl.net/SG11WP1/itu-t-sg11-del-contrib-
      d398.pdf).


Acknowledgments

      I would like to thank Kenichi Kitami of the NTT Network Innovation
      Planning and Promotion Dept., who is also the chair of ITU-T SG11
      WP1, Shinichi Kuribayashi of the NTT Business Communications Hqs.,
      Hiroshi Yao and Takumi Ohba of the NTT Network Service Systems
      Labs., and Noriyuki Takahashi of the NTT Multimedia Networks Labs.
      for their valuable comments and discussions.

      And I would also like to thank the active members of IETF, ITU-T,
      and ATM Forum, especially Joel Halpern of Newbridge Networks, for
      their valuable comments and suggestions.




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      Also this specification is based on various discussions during the
      ST2+ over ATM project at the NTT Multimedia Joint Project with
      NACSIS.  I would like to thank Professor Shoichiro Asano of the
      National Center for Science Information Systems for his invaluable
      advice in this area.


Author's Address

      Muneyoshi Suzuki
      NTT Multimedia Networks Laboratories
      3-9-11, Midori-cho
      Musashino-shi, Tokyo 180, Japan

      Phone: +81-422-59-2119
      Fax:   +81-422-59-3203
      EMail: suzuki@nal.ecl.net


































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