path: root/doc/rfc/rfc3475.txt

Network Working Group                                      O. Aboul-Magd
Request for Comments: 3475                               Nortel Networks
Category: Informational                                       March 2003


                 Documentation of IANA assignments for
        Constraint-Based LSP setup using LDP (CR-LDP) Extensions
             for Automatic 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

   Automatic Switched Optical Network (ASON) is an architecture,
   specified by ITU-T Study Group 15, for the introduction of a control
   plane for optical networks.  The ASON architecture specifies a set of
   reference points that defines the relationship between the ASON
   architectural entities.  Signaling over interfaces defined in those
   reference points can make use of protocols that are defined by the
   IETF in the context of Generalized Multi-Protocol Label Switching
   (GMPLS) work.  This document describes Constraint-Based LSP setup
   using LDP (CR-LDP) extensions for signaling over the interfaces
   defined in the ASON reference points.  The purpose of the document is
   to request that the IANA assigns code points necessary for the CR-LDP
   extensions.  The protocol specifications for the use of the CR-LDP
   extensions are found in ITU-T documents.

Table of Contents

   1.  Introduction .................................................  2
   2.  Overview of CR-LDP Extensions for ASON .......................  2
   3.  CR-LDP Messages for ASON .....................................  3
      3.1 Call Setup Message ........................................  4
         3.1.2 Call Setup Procedure .................................  5
      3.2 The Call Release Message ..................................  5
         3.2.1 Call Release Procedure ...............................  6
   4.  CR-LDP TLV for ASON ..........................................  6
      4.1 Call ID TLV ...............................................  6
         4.1.1 Call ID Procedure ....................................  8
      4.2 Call Capability TLV .......................................  9



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      4.3 Crankback TLV .............................................  9
   5.  Additional Error Codes ....................................... 10
   6.  IANA Consideration ........................................... 11
   9.  Security Considerations ...................................... 11
   10. Normative References ......................................... 11
   11. Intellectual Property ........................................ 12
   12. Author's Address ............................................. 12
   13. Full Copyright Statement ..................................... 13

1. Introduction

   Automatic Switched Optical Network (ASON) is an architecture,
   specified by ITU-T Study Group 15 (SG15), for the introduction of a
   control plane for optical networks.  The development and the
   standardization of ASON has been done by ITU-T SG15 and is documented
   in recommendation G.8080 [1].  The architecture includes a control
   plane with a set of reference points between the architectural
   components.  The ASON signaling that runs over interfaces defined in
   those reference points are described in ITU-T recommendation G.7713
   [2].

   Constraint-Based LSP Setup using LDP (CR-LDP) [3] is one of the
   protocols selected by the ITU for the realization of G.7713 and its
   dynamic connection management. The work specific to CR-LDP extensions
   for ASON is documented in ITU-T recommendation G.7713.3 [8].

   This document introduces those CR-LDP extensions that are specific to
   ASON and requests IANA allocation of code points for these
   extensions.  The document does not specify how these extensions are
   used; that is the subject of the above mentioned ITU-T documents.
   This document should be considered in conjunction with RFC 3036 [4],
   RFC 3212 [3], and CR-LDP extensions for GMPLS [5].

2. Overview of CR-LDP Extensions for ASON

   This document describes ASON specific CR-LDP extensions covering the
   following ASON signaling requirements:

   - Call and connection control separation
   - Support of Soft Permanent Connections (SPC)
   - Crankback
   - Additional error codes

   An important ASON architectural principle is the separation between
   the call and the connection controllers as described in G.8080.  Call
   and connection control separation allows for a call with multiple
   connections associated with it.  It also allows for a call with no




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   connections (a temporary situation that might be useful during
   recovery).

   The separation of the call and the connection controllers could be
   achieved using one of two models.  The first model is one where the
   call set up request is always accompanied by a connection request.
   The second model is one in which call set up is done independently
   from connection set up.  The first model is usually referred to as
   logical separation, while the second model is usually referred to as
   complete separation.  CR-LDP extensions for ASON support the two
   separation models.

   Two new messages are introduced for call operations (set up and
   release).  The Call Setup message is used for those cases where
   complete separation is required.  Otherwise the LDP Label Request
   message is used for logical separation.

   A connection set up request must indicate the call to which the
   connection needs to be associated.  A Call ID TLV is introduced to
   achieve this goal.  The structure of the Call ID allows it to have a
   global or an operator scope.

   Call release is always achieved using the Call Release message.  The
   reception of the call Release messages signifies the intention to
   remove all connections that are associated to the call.  Connection
   release is achieved using the CR-LDP label release procedure (using
   LDP Label Release and Label Withdraw messages) as defined in [4].

   A Call Capability TLV is also introduced to explicitly indicate the
   capability of the requested call.

   An Soft Permanent Connection (SPC) service assumes that both source
   and destination user-to-network connection segments are provisioned
   while the network connection segment is set up via the control plane.
   For example when the initial request is received from an external
   source, e.g. from a management system, there is an implicit
   assumption that the control plane has adequate information to
   determine the specific destination (network-to-user) link connection
   to use.  Support for CR-LDP is provided by the use of the Egress
   Label TLV as defined in the OIF UNI 1.0 section 11.7.5 [6] from the
   Optical Internetworking Forum and in RFC3476 [7].

3. CR-LDP Messages for ASON

   This section describes the formats and the procedures of the two
   messages that are required for ASON call and connection control
   separation.  Those messages are the Call Setup messages and the Call
   Release message.



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3.1 Call Setup Message

   The format of the Call Setup message is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|  Call Setup (0x0500)        |      Length                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Message ID                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Source ID TLV                       |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Dest ID  TLV                        |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Call ID TLV                         |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Call Capability TLV                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Optional Parameters                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Message ID:
      Is as defined in RFC3036 [4].

   Source ID TLV:
      Is as defined in UNI 1.0 [6] and in [7].

   Dest ID TLV:
      Is as defined in UNI 1.0 [6] and in [7].

   Call ID TLV:
      Is as defined in section 4.1 of this document.

   Call Capability TLV:
     Is as defined in section 4.2 of this document.








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3.1.2 Call Setup Procedure

   The Calling party sends the Call Setup message whenever a new call
   needs to be set up with no connection associated with it.  The Call
   Setup message shall contain all the information required by the
   network to process the call.  In particular, the Call Setup message
   shall include the calling and called party addresses as specified by
   the Source ID and Dest ID TLV.  The setup message must include Call
   ID TLV.  The call control entity shall identify the call using the
   selected identifier for the lifetime of the call.  The Call Setup
   message shall progress through the network to the called party.  The
   called party may accept or reject the incoming call.  An LDP
   Notification message with the appropriate status code shall be used
   to inform the calling party whether the setup is successful.  The
   call can be rejected by either the network, e.g. for policy reasons,
   or by the called party.

3.2 The Call Release Message

   This format of the Call Release message is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0| Call Release (0x0501)       |      Length                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Message ID                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Source ID TLV                       |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Dest ID TLV                         |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Call ID TLV                         |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Optional Parameters                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+








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3.2.1 Call Release Procedure

   The Call Release message is sent by any entity of the network to
   terminate an already established call.  The Call Release message must
   include the Call ID TLV of the call to be terminated.  Confirmation
   of call release is indicated to the request initiator using a
   Notification message with the appropriate status code.  Reception and
   processing of the Call Release message must trigger the release of
   all connections that are associated with that call.  Connection
   release follows the normal CR-LDP procedure using Label Release and
   Label Withdraw messages.

4. CR-LDP TLVs for ASON

   This section describes the operator specific Call ID TLV, the
   globally unique Call ID TLV, the Call Capability TLV and the
   Crankback TLV introduced for ASON.

4.1 Call ID TLV

   An established call may be identified by a Call ID.  The Call ID is a
   globally unique identifier that is set by the source network.  The
   structure for the Call ID (to guarantee global uniqueness) is to
   concatenate a globally unique fixed identifier (composed of country
   code, carrier code, unique access point code) with an operator
   specific identifier (where the operator specific identifier is
   composed of ingress network element (NE) 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 <NE
   address> plus <local Identifier>).  For a CALL_ID that requires only
   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.










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   The format of the operator specific (Op-Sp) CALL_ID TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |U|F|Op-Sp Call ID (0x0831)     |      Length                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   NE Address (NEA Sub TLV)                    |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Local Identifier                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Local Identifier (continued)                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   NEA Sub TLV:
      The Source NE Address is an address of the transport network
      element controlled by the source network.  Its length can be 4, 6,
      16, or 20 bytes long.  The NEA Sub TLV is TLV Type 1.

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

   The format of the globally unique (GU) Call ID TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |U|F|GU Call ID (0x0832)        |      Length                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Reserved      |                    IS                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             NS                                |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   NE Address (NEA Sub TLV)                    |
      ~                                                               ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Local Identifier                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Local Identifier (continued)                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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   International Segment (IS):
      To 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 is 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.

   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)            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

4.1.1 Call ID Procedure

   The following processing rules are applicable to the CALL ID TLV:

   -  For initial calls, the calling/originating party call controller
      must set the CALL ID values to all-zeros.




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   -  For a new call request, the source networks call controller (SNCC)
      sets the appropriate type and value for the CALL ID.
   -  For an existing call (in case Call ID is non zero) the SNCC
      verifies existence of the call.
   -  Intermediate nodes are not allowed to alter the Call ID TLV set by
      the ingress node.
   -  The destination user/client receiving the request uses the CALL ID
      values 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.

4.2 Call Capability TLV

   The format of the Call Capability TLV is:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |U|F| Call Capabaility(0x0833)  |      Length                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Call Capability                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Call Capability TLV contains a 4 byte Call Capability field.  The
   Call Capability Field is used to explicitly indicate the
   configuration potentiality of the call.

   An example of values of the Call Capability field is:

      0x0000   Point to Point call

4.3 Crankback TLV

   Crankback requires that when the Label Request message is blocked at
   a particular node due to unavailable resources, the node will inform
   the initiator of the Label Request message of the location of the
   blockage.  The initiator can then re-compute new explicit routes that
   avoid the area where resource shortage is detected.  A new Label
   Request message is sent that includes the new route.

   The support of crankback in CR-LDP is facilitated by the introduction
   of a Crankback TLV.  An LDP Notification message is used to inform
   the Label Request message initiator of the blocking condition.  The
   Notification message includes the Crankback TLV that indicates the
   location of resource shortage.  The location of the resource shortage
   is identified using the ER-HOP TLV.  The encoding of the Crankback
   TLV is:



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       0                   1                   2                   3

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |U|F| Crankback(0x0834)         |      Length                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                       ER-HOP TLV                              ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The ER-HOP TLV is specified in rfc3212 [3], and consists of an n x 4
   bytes field, it could e.g. contain an IPv4 or an IPv6 address.

5. Additional Error Codes

   G.7713 includes a number of error codes that are currently not
   defined in earlier CR-LDP related RFCs.  The list of those error
   conditions is given below:

      Invalid SNP ID (0x04000009)
      Calling Party busy (0x0400000a)
      Unavailable SNP ID (0x0400000b)
      Invalid SNPP ID (0x0400000c)
      Unavailable SNPP ID (0x0400000d)

      Failed to create SNC (0x0400000e)
      Failed to establish LC (0x040000f)
      Invalid Source End-User Name (0x04000010)
      Invalid Destination End-User Name (0x04000011)
      Invalid CoS (0x04000012)
      Unavailable CoS (0x04000013)
      Invalid GoS (0x04000014)
      Unavailable GoS (0x04000015)
      Failed Security Check (0x04000016)
      TimeOut (0x04000017)
      Invalid Call Name (0x04000018)
      Failed to Release SNC (0x04000019)
      Failed to Free LC (0x0400001a)

   Acronyms used in above error codes:

      SNP    Sub-network Point
      SNPP   Sub-network Point Pool
      SNC    Sub-network Connection
      LC     Link Connection
      CoS    Class of Service
      GoS    Grade of Service





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6. IANA Consideration

   This document uses the LDP RFC 3036 [4] name spaces; see
   http://www.iana.org/assignments/ldp-namespaces.

      Call Setup (0x0500)
      Call Release (0x0501)

   The assignment for the following TLVs:

      Op-Sp Call ID TLV (0x0831)
      GU Call ID TLV (0x0832)
      Call Capability TLV (0x0833)
      Crankback TLV (0x0834)

   The assignment for the new error codes as listed in section 5 of this
   document.

9. Security Considerations

   This document does not introduce any new security concerns other than
   those defined in RFC 3036 and RFC 3212.

   Security aspects (if any) w.r.t. the G.8080 and G.7713 documents need
   to be addressed in those documents.

10. Normative References

   [1] Architecture for Automatically Switched Optical Network (ASON),
       ITU-T recommendation G.8080, Nov. 2001

   [2] Distributed Call and Connection Management (DCM), ITU-T
       recommendation G.7713, Dec. 2001

   [3] Jamoussi, B., Ed., Andersson, L., Callon, R., Dantu, R., Wu, L.,
       Doolan, P., Worster, T., Feldman, N., Fredette, A., Girish, M.,
       Gray, E., Heinanen, J., Kilty, T. and A. Malis, "Constraint-Based
       LSP Setup using LDP", RFC 3212, January 2002.

   [4] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and B.
       Thomas, "LDP Specifications", RFC 3036, January 2001.

   [5] Ashwood-Smith, P. and L. Berger, (Editors),"Generalized Multi-
       Protocol Label Switching (GMPLS) Signaling Constraint-based
       Routed Label Distribution Protocol (CR-LDP) Extensions", RFC
       3472, January 2003.





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

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

   [8] Distributed Call and Connection Management signalling using GMPLS
       CR-LDP, ITU G.7713.3, Januray 2003.

11. 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.

   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.

12. Author's Addresses

   Osama Aboul-Magd
   Nortel Networks
   P.O. Box 3511, Station C
   Ottawa, Ontario, Canada
   K1Y 4H7
   Phone: 613-599-9104
   EMail: osama@nortelnetworks.com










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13. 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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