rfc3525.txt

OTP是开放电信平台的简称

   -  This document includes a new Appendix II listing all the changes
      from RFC 3015.

   -  This document includes an Acknowledgements section listing the
      authors of RFC 3015 but also many other people who contributed to
      the development of the Megaco/H.248.x protocol.

   -  Moved the Intellectual Property declaration to its usual place in
      an IETF document and added a reference to declarations on the IETF
      web site.

2  References

   The following ITU-T Recommendations and other references contain
   provisions which, through reference in this text, constitute
   provisions of this RFC.  At the time of publication, the editions
   indicated were valid.  All Recommendations and other references are
   subject to revision; all users of this RFC are therefore encouraged
   to investigate the possibility of applying the most recent edition of
   the Recommendations and other references listed below.  A list of the
   currently valid ITU-T Recommendations is regularly published.

2.1   Normative references

   -  ITU-T Recommendation H.225.0 (1999), Call signalling protocols and
      media stream packetization for packet-based multimedia
      communication systems.



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RFC 3525                Gateway Control Protocol               June 2003


   -  ITU-T Recommendation H.235 (1998), Security and encryption for
      H-Series (H.323 and other H.245-based) multimedia terminals.

   -  ITU-T Recommendation H.245 (1998), Control protocol for multimedia
      communication.

   -  ITU-T Recommendation H.246 (1998), Interworking of H-series
      multimedia terminals with H-series multimedia terminals and
      voice/voiceband terminals on GSTN and ISDN.

   -  ITU-T Recommendation H.248.8 (2002), H.248 Error Codes and Service
      Change Reasons.

   -  ITU-T Recommendation H.323 (1999), Packet-based multimedia
      communication systems.

   -  ITU-T Recommendation I.363.1 (1996), B-ISDN ATM adaptation layer
      (AAL) specification: Type 1 AAL.

   -  ITU-T Recommendation I.363.2 (1997), B-ISDN ATM adaptation layer
      (AAL) specification: Type 2 AAL.

   -  ITU-T Recommendation I.363.5 (1996), B-ISDN ATM adaptation layer
      (AAL) specification: Type 5 AAL.

   -  ITU-T Recommendation I.366.1 (1998), Segmentation and Reassembly
      Service Specific Convergence Sublayer for the AAL type 2.

   -  ITU-T Recommendation I.366.2 (1999), AAL type 2 service specific
      convergence sublayer for trunking.

   -  ITU-T Recommendation I.371 (2000), Traffic control and congestion
      control in B-ISDN.

   -  ITU-T Recommendation Q.763 (1999), Signalling System No. 7 - ISDN
      user part formats and codes.

   -  ITU-T Recommendation Q.765.5 (2001), Application transport
      mechanism - Bearer independent call control (BICC).

   -  ITU-T Recommendation Q.931 (1998), ISDN user-network interface
      layer 3 specification for basic call control.

   -  ITU-T Recommendation Q.2630.1 (1999), AAL type 2 signalling
      protocol (Capability Set 1).






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RFC 3525                Gateway Control Protocol               June 2003


   -  ITU-T Recommendation Q.2931 (1995), Digital Subscriber Signalling
      System No. 2 (DSS2) - User-Network Interface (UNI) - Layer 3
      specification for basic call/connection control.

   -  ITU-T Recommendation Q.2941.1 (1997), Digital Subscriber
      Signalling System No. 2 - Generic identifier transport.

   -  ITU-T Recommendation Q.2961.1 (1995), Additional signalling
      capabilities to support traffic parameters for the tagging option
      and the sustainable call rate parameter set.

   -  ITU-T Recommendation Q.2961.2 (1997), Additional traffic
      parameters: Support of ATM transfer capability in the broadband
      bearer capability information element.

   -  ITU-T Recommendation Q.2965.1 (1999), Digital subscriber
      signalling system No. 2 - Support of Quality of Service classes.

   -  ITU-T Recommendation Q.2965.2 (1999), Digital subscriber
      signalling system No. 2 - Signalling of individual Quality of
      Service parameters.

   -  ITU-T Recommendation V.76 (1996), Generic multiplexer using V.42
      LAPM-based procedures.

   -  ITU-T Recommendation X.213 (1995), Information technology - Open
      Systems Interconnection - Network service definition plus
      Amendment 1 (1997), Addition of the Internet protocol address
      format identifier.

   -  ITU-T Recommendation X.680 (1997), Information technology -
      Abstract Syntax Notation One (ASN.1): Specification of basic
      notation.

   -  ITU-T Recommendation X.690 (1997), Information Technology - ASN.1
      Encoding Rules: Specification of Basic Encoding Rules (BER),
      Canonical Encoding Rules (CER) and Distinguished Encoding Rules
      (DER).

   -  ATM Forum (1996), ATM User-Network Interface (UNI) Signalling
      Specification - Version 4.0.

   [RFC 1006] Rose, M. and D. Cass, "ISO Transport Service on top of the
              TCP, Version 3", STD 35, RFC 1006, May 1987.

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




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

   [RFC 2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, November 1997.

   [RFC 2327] Handley, M. and V. Jacobson, "SDP: Session Description
              Protocol", RFC 2327, April 1998.

   [RFC 2402] Kent, S. and R. Atkinson, "IP Authentication Header", RFC
              2402, November 1998.

   [RFC 2406] Kent, S. and R. Atkinson, "IP Encapsulating Security
              Payload (ESP)", RFC 2406, November 1998.

2.2   Informative references

   -  ITU-T Recommendation E.180/Q.35 (1998), Technical characteristics
      of tones for the telephone service.

   -  CCITT Recommendation G.711 (1988), Pulse Code Modulation (PCM) of
      voice frequencies.

   -  ITU-T Recommendation H.221 (1999), Frame structure for a 64 to
      1920 kbit/s channel in audiovisual teleservices.

   -  ITU  T Recommendation H.223 (1996), Multiplexing protocol for low
      bit rate multimedia communication.

   -  ITU-T Recommendation H.226 (1998), Channel aggregation protocol
      for multilink operation on circuit-switched networks

   -  ITU-T Recommendation Q.724 (1998), Signalling procedures.

   -  ITU-T Recommendation Q.764 (1999), Signalling system No. 7 - ISDN
      user part signalling procedures.

   -  ITU-T Recommendation Q.1902.4 (2001), Bearer independent call
      control protocol - Basic call procedures.

   [RFC 768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              August 1980.

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

   [RFC 793]  Postel, J., "Transmission Control Protocol", STD 7, RFC
              793, September 1981.



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RFC 3525                Gateway Control Protocol               June 2003


   [RFC 1661] Simpson, W., Ed., "The Point-to-Point Protocol (PPP)", STD
              51, RFC 1661, July 1994.

   [RFC 1889] Schulzrinne, H., Casner, S., Frederick, R. and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", RFC 1889, January 1996.

   [RFC 1890] Schulzrinne, H. and G. Fokus, "RTP Profile for Audio and
              Video Conferences with Minimal Control",  RFC 1890,
              January 1996.

   [RFC 2401] Kent, S. and R. Atkinson, "Security Architecture for the
              Internet Protocol", RFC 2401, November 1998.

   [RFC 2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC 2543] Handley, M., Schulzrinne, H., Schooler, E. and J.
              Rosenberg, "SIP: Session Initiation Protocol", RFC 2543,
              March 1999.

   [RFC 2805] Greene, N., Ramalho, M. and B. Rosen, "Media Gateway
              Control Protocol Architecture and Requirements", RFC 2805,
              April 2000.

3  Definitions

   This document defines the following terms:

   Access gateway:
   A type of gateway that provides a User-Network Interface (UNI) such
   as ISDN.

   Descriptor:
   A syntactic element of the protocol that groups related properties.
   For instance, the properties of a media flow on the MG can be set by
   the MGC by including the appropriate descriptor in a command.

   Media Gateway (MG):
   The media gateway converts media provided in one type of network to
   the format required in another type of network.  For example, a MG
   could terminate bearer channels from a switched circuit network
   (e.g., DS0s) and media streams from a packet network (e.g., RTP
   streams in an IP network).  This gateway may be capable of processing
   audio, video and T.120 alone or in any combination, and will be
   capable of full duplex media translations.  The MG may also play
   audio/video messages and perform other IVR functions, or may perform
   media conferencing.



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   Media Gateway Controller (MGC):
   Controls the parts of the call state that pertain to connection
   control for media channels in a MG.

   Multipoint Control Unit (MCU):
   An entity that controls the setup and coordination of a multi-user
   conference that typically includes processing of audio, video and
   data.

   Residential gateway:
   A gateway that interworks an analogue line to a packet network.  A
   residential gateway typically contains one or two analogue lines and
   is located at the customer premises.

   SCN FAS signalling gateway:
   This function contains the SCN Signalling Interface that terminates
   SS7, ISDN or other signalling links where the call control channel
   and bearer channels are collocated in the same physical span.

   SCN NFAS signalling gateway:
   This function contains the SCN Signalling Interface that terminates
   SS7 or other signalling links where the call control channels are
   separated from bearer channels.

   Stream:
   Bidirectional media or control flow received/sent by a media gateway
   as part of a call or conference.

   Trunk:
   A communication channel between two switching systems such as a DS0
   on a T1 or E1 line.

   Trunking gateway:
   A gateway between SCN network and packet network that typically
   terminates a large number of digital circuits.

4  Abbreviations

   This RFC document uses the following abbreviations:

   ALF   Application Layer Framing

   ATM   Asynchronous Transfer Mode

   CAS   Channel Associated Signalling