📄 rfc1755.txt
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# 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 supported9. 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.Perez, Liaw, Mankin, Hoffman, Grossman & Malis [Page 18]RFC 1755 ATM Signaling Support for IP over ATM February 199510. 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.Perez, Liaw, Mankin, Hoffman, Grossman & Malis [Page 19]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: 703-807-0132 EMail: perez@isi.edu Fong-Ching Liaw FORE Systems, Inc. 174 Thorn Hill Road Warrendale, PA 15086-7535 Phone: (412) 772-8668 EMail: fong@fore.com Allison Mankin USC/Information Sciences Institute 4350 N. Fairfax Drive Suite 400 Arlington, VA 22203 Phone: 703-807-0132 EMail: mankin@isi.eduPerez, Liaw, Mankin, Hoffman, Grossman & Malis [Page 20]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: 703-807-0132 EMail: hoffman@isi.edu Dan Grossman Motorola Codex Phone: 617-821-7333 EMail: dan@merlin.dev.cdx.mot.com Andrew G. Malis Ascom Timeplex, Inc. Advanced Products Business Unit 289 Great Road Suite 205 Acton, MA 01720 Phone: (508) 266-4522 EMail: malis@maelstrom.timeplex.comPerez, Liaw, Mankin, Hoffman, Grossman & Malis [Page 21]RFC 1755 ATM Signaling Support for IP over ATM February 1995Appendix A. Sample Signaling Messages1. 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)Perez, Liaw, Mankin, Hoffman, Grossman & Malis [Page 22]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]Perez, Liaw, Mankin, Hoffman, Grossman & Malis [Page 23]RFC 1755 ATM Signaling Support for IP over ATM February 1995 In IP over ATM environments the inclusion of the "AAL parameters" IE is *mandatory* to allow for MTU size negotiation between the source and destination. The "Broadband Low Layer Information" IE is also mandatory for specifying the IP encapsulation scheme. +--------------------------------------------------------------------+ CONNECT Information Elements/ Fields Value -------------------- ----- aal_parameters aal_type 5 (AAL 5) fwd_max_sdu_size_ident 140
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