rfc1755.txt

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8.  Dealing with Failure of Call Establishment

   If an ATM call attempt fails with any of the following causes, the
   situation SHOULD be treated as Network Unreachable (if the called ATM
   endsystem is a router) or Host Unreachable (if the called ATM
   endsystem is a host).  See the treatment of Network and Host
   Unreachable conditions in RFC 1122 [BRAD89].

        #  1  unallocated (unassigned) number
        #  3  no route to destination
        # 17  user busy
        # 18  no user reponding
        # 27  destination out of order
        # 38  network out of order
        # 41  temporary failure
        # 47  resource unavailable, unspecified

   If an ATM call attempt fails with any of the following causes, the
   ATM endsystem MAY retry the call, changing (or adding) the IE(s)
   indicated by the cause code and diagnostic.

           #  2  no route to specified transit network
           # 21  call rejected
           # 22  number changed
           # 23  user rejects call with CLIR
           # 37  user cell rate unavailable
           # 49  quality of service unavailable
           # 57  bearer capability not authorized
           # 58  bearer capability not presently available
           # 65  bearer capability not implemented
           # 73  unsupported combination of traffic parameter
           # 88  incompatible destination
           # 91  invalid transmit network selection
           # 78  AAL parameter cannot be supported

9.  Security Considerations

   Not all of the security issues relating to IP over ATM are clearly
   understood at this time, due to the fluid state of ATM
   specifications, newness of the technology, and other factors.  Future
   revisions of this specification will address the security
   capabilities that future signaling standards may offer to IP over ATM
   signaling.








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RFC 1755         ATM Signaling Support for IP over ATM     February 1995


10.  Open Issues

   o   This document version is specifically an RFC 1577/RFC 1483
       implementation document. Although RFC 1577 and RFC 1483
       specify an LLC/SNAP encapsulation, which is inherently a
       multiprotocol encapsulation, it is beyond to scope of this
       document to go into any multiprotocol specifications other than
       to point out some examples (see Appendix D for an example of
       NLPID encapsulation).

11.  Acknowledgments

   The authors wish to thank the work of their colleagues who attend the
   IP over ATM working group; the ATM Forum Technical Committee; the ATM
   Signaling Subworking Group in ANSI-Accredited Technical Subcommittee
   T1S1; the ATM Access Signaling experts in ITU-T (formerly CCITT)
   Study Group 11. Rao Cherukuri (IBM) and Jeff Kiel (formerly with
   Bellcore, presently with BellSouth) were particularly valuable in
   coordinating among T1S1, ITU-T and the ATM Forum to make sure that
   the needs of multiprotocol over ATM could be expressed in the ATM
   signaling protocol.

REFERENCES

   [ATKI94] Atkinson, R., "Default IP MTU over ATM AAL5", RFC 1626,
       Naval Research Laboratory, May 1994.

   [ATMF94] ATM Forum, "ATM User-Network Interface Specification Version
       3.1", 1994.

   [ATMF93] ATM Forum, "ATM User-Network Interface Specification Version
       3.0", (Englewood Cliffs, NJ: Prentice Hall, 1993).

   [BRAD89] Braden, R., Editor, "Requirements for Internet Hosts --
       Communication Layers", STD 3, RFC 1122, USC/Information Science
       Institute, October 1989.

   [BRAD94] Braden, R., Clark, D., and S. Shenker, "Integrated Service
       in the Internet Architecture:  An Overview", RFC 1633,
       USC/Information Science Institute, June 1994.

   [BRAD92] Bradley, T., and C. Brown, "Inverse Address Resolution
       Protocol", RFC 1293, Wellfleet Communications, Inc., January
       1992.

   [HEIN93] Heinanen, J., "Multiprotocol Encapsulation over ATM
       Adaptation Layer 5", RFC 1483, Telecom Finland, July 1993.




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RFC 1755         ATM Signaling Support for IP over ATM     February 1995


   [ISO8473] ISO/IEC 8473, Information processing systems - Data
       communications - Protocol for providing the connectionless-mode
       network service, 1988.

   [ISO9577] Information Technology - Telecommunication and information
       exchange between systems - Protocol identification in the network
       layer ISO/IEC TR9577 (International Standards Organization:
       Geneva, 1990).

   [LAUB93] Laubach, M., "Classical IP and ARP over ATM", RFC 1577,
       Hewlett-Packard Laboratories, December 1993.

   [PART92] Partridge, C., "A Proposed Flow Specification", RFC 1363,
       BBN, September 1992.

   [Q.2931] Broadband Integrated Service Digital Network (B-ISDN)
       Digital Subscriber Signaling System No.2 (DSS2) User Network
       Interface Layer 3 Specification for Basic Call/Connection Control
       ITU-T Recommendation Q.2931, (International Telecommunication
       Union: Geneva, 1994)

Authors' Addresses

   Maryann Perez Maher
   USC/Information Sciences Institute
   4350 N. Fairfax Drive Suite 400
   Arlington, VA 22203

   Phone: [phone]
   EMail: [e-mail]


   Fong-Ching Liaw
   FORE Systems, Inc.
   174 Thorn Hill Road
   Warrendale, PA 15086-7535

   Phone: [phone]
   EMail: [e-mail]


   Allison Mankin
   USC/Information Sciences Institute
   4350 N. Fairfax Drive Suite 400
   Arlington, VA 22203

   Phone:  [phone]
   EMail: [e-mail]



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RFC 1755         ATM Signaling Support for IP over ATM     February 1995


   Eric Hoffman
   USC/Information Sciences Institute
   4350 N. Fairfax Drive Suite 400
   Arlington, VA 22203

   Phone:  [phone]
   EMail: [e-mail]


   Dan Grossman
   Motorola Codex

   Phone: [phone]
   EMail: [e-mail]


   Andrew G. Malis
   Ascom Timeplex, Inc.
   Advanced Products Business Unit
   289 Great Road   Suite 205
   Acton, MA  01720

   Phone: [phone]
   EMail: [e-mail]



























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RFC 1755         ATM Signaling Support for IP over ATM     February 1995


Appendix A. Sample Signaling Messages

1. SETUP and CONNECT messages

   This appendix shows sample codings of the SETUP and CONNECT signaling
   messages. The fields in the IE header are not shown.

  +--------------------------------------------------------------------+
                                SETUP

    Information Elements/
      Fields                         Value/(Meaning)
    --------------------             ---------------

    aal_parameters
      aal_type                       5        (AAL 5)
      fwd_max_sdu_size_ident         140
      fwd_max_sdu_size               (send IP MTU value)
      bkw_max_sdu_size_ident         129
      bkw_max_sdu_size               (recv IP MTU value)
      sscs_type identifier           132
      sscs_type                      0        (null SSCS)

    user_cell_rate
      fwd_peak_cell_rate_0_1_ident   132
      fwd_peak_cell_rate_0_1         (link rate)
      bkw_peak_cell_rate_0_1_ident   133
      bkw_peak_cell_rate_0_1         (link rate)
      best_effort_indication         190

    bb_bearer_capability
      spare                          0
      bearer_class                   16       (BCOC-X)
      spare                          0
      traffic_type                   0        (no indication)
      timing_reqs                    0        (no indication)
      susceptibility_to_clipping     0        (not susceptible to
                                              clipping)
      spare                          0
      user_plane_configuration       0        (point_to_point)

    bb_low_layer_information
      layer_2_id                     2
      user_information_layer         12       (lan_llc (ISO 8802/2)

    qos_parameter
      qos_class_fwd                  0        (class 0)
      qos_class_bkw                  0        (class 0)



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RFC 1755         ATM Signaling Support for IP over ATM     February 1995


    called_party_number
      type_of_number                 (international number / unknown)
      addr_plan_ident                (ISDN / ATM Endsystem Address)
      number                         (E.164 / ATM Endsystem Address)

    calling_party_number
      type_of_number                 (international number / unknown)
      addr_plan_ident                (ISDN / ATM Endsystem Address)
      presentation_indic             (presentation allowed)
      spare                          0
      screening_indic                (user_provided verified and passed)
      number                         (E.164 / ATM Endsystem Address)

  +--------------------------------------------------------------------+
                              Figure 1.
                      Sample contents of SETUP message

  [* : optional, ignored if present]