1、 International Telecommunication Union ITU-T H.248.51TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (08/2007) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: Termination connection model package ITU-T Recommendati
2、on H.248.51 ITU-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES General H.200H.219 Transmission multiplexing and synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures
3、H.240H.259 Coding of moving video H.260H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349 Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture for audiovisual and multimedia service
4、s H.360H.369 Supplementary services for multimedia H.450H.499 MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definitions, protocols and procedures H.500H.509 Mobility for H-Series multimedia systems and services H.510H.519 Mobile multimedia collaboration applications a
5、nd services H.520H.529 Security for mobile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND AND TRIPLE-
6、PLAY MULTIMEDIA SERVICES Broadband multimedia services over VDSL H.610H.619 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. H.248.51 (08/2007) i ITU-T Recommendation H.248.51 Gateway control protocol: Termination connection model package Summary ITU-T Recommendatio
7、n H.248.51 contains a H.248 package that enables a media gateway controller to audit a media gateway to determine what termination connection configurations are allowed in a context. The termination connection configuration may be the particular termination types allowed to be connected together, an
8、d/or the maximum number of a particular termination type allowed in a context for a multi-terminations scenario, e.g., conference or multicast. Source ITU-T Recommendation H.248.51 was approved on 29 August 2007 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU
9、-T Rec. H.248.51 (08/2007) The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is re
10、sponsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by th
11、e ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collabor
12、ative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain
13、mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements.
14、 The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU t
15、akes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual pro
16、perty, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2008 All rights reserve
17、d. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. H.248.51 (08/2007) iii CONTENTS Page 1 Scope 1 1.1 Relationship with H.248.38 property “number of terminations in a context“. 1 1.2 Relationship with multiplexed termina
18、tions. 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation. 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Termination Connection Model Package . 3 6.1 Properties 3 6.2 Events . 4 6.3 Signals 4 6.4 Statistics 4 6.5 Error Codes. 4 6.6 Procedure
19、s 4 ITU-T Rec. H.248.51 (08/2007) 1 ITU-T Recommendation H.248.51 Gateway control protocol: Termination connection model package 1 Scope This package allows a media gateway controller to audit a media gateway in order to determine what termination connection configurations are allowed in a context.
20、It provides the media gateway controller an automatic means to determine the information contained in Appendix III of ITU-T H.248.1, clause 6.4 “Connection Model“. Based on this information, the media gateway controller should use the allowed termination connection configurations in its indication t
21、o the media gateway for connecting terminations in a context, thereby avoiding the potential failure. The termination connection configuration may be the termination types allowed to be connected together, and/or the maximum number of a particular termination type allowed in a context for a multi-te
22、rminations scenario, e.g., conference or multicast. It provides an enhanced capability of topology auditing to unambiguously describe the allowed termination connection configurations. In order to provide a mapping between the type of termination and the TerminationID, a meaningful TerminationID sch
23、eme should be used. This scheme shall be provisioned on both the MGC and MG. Using a meaningful scheme allows the TerminationID to be wildcarded in order to describe the terminations connection configurations. Even where this package is not implemented by a media gateway, the descriptions and syntax
24、 described in this Recommendation may be used by those defining Profiles when describing the connection model section of the H.248 Profile Template (Appendix III of ITU-T H.248.1, clause 6.4). 1.1 Relationship with H.248.38 property “number of terminations in a context“ H.248.51 is about termination
25、 connection configurations, which are allowed in a possible context, whereas H.248.38 bc/numterm property is about the number of terminations present in a concrete, established context. Both functionalities are thus disjoint. 1.2 Relationship with multiplexed terminations Multiplexed terminations ar
26、e defined in clauses 6.2 (Terminations) and 7.1.3 (Multiplex Descriptor) of ITU-T H.248.1. This Recommendation does not allow the description of Termination Connection Models (see clause 3.2.1) with multiplexed termination types. 2 References The following ITU-T Recommendations and other references
27、contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigat
28、e 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. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status o
29、f a Recommendation. ITU-T H.248.1 ITU-T Recommendation H.248.1 (2005), Gateway control protocol: Version 3. ITU-T Q.1950 ITU-T Recommendation Q.1950 (2002), Bearer independent call bearer control protocol. 2 ITU-T Rec. H.248.51 (08/2007) ETSI TS 129 232 ETSI TS 129 232 v6.9.0 (2007), Universal Mobil
30、e Telecommunications System (UMTS); Media Gateway Controller (MGC) Media Gateway (MGW) interface; Stage 3 (3GPP TS 29.232 version 6.9.0 Release 6). 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation defines the following term: 3.2.1 terminati
31、on connection model: Such a model is characterized by: a) (maximum) number of terminations per context; b) possible termination types (Note 1) in such a context; c) possible topologies between the terminations in such a context; and d) supported topology associations for each possible topology in su
32、ch a context. A MG may support one or multiple different termination connection model(s). The termination type is typically related to a specific bearer technology (Note 2) of the termination. NOTE 1 The type of a termination may be visible via the Termination Identifier (Tid). For instance, H.248 P
33、rofile specifications often define “prefix“ elements (e.g., ALN, TDM, IP, RTP, Ephemeral, AAL2, etc.) as part of the Tid names (for H.248 text encoding). Another example is dedicated codepoints, like the 3-bit termination type codepoint in ETSI TS 129 232, in ASN.1 coding schemes (for H.248 binary e
34、ncoding). Such a prefix or codepoint may be used for unambiguous indications of a termination type. NOTE 2 H.248 implementations may not support a means to determine the bearer type through the Termination Identifier. In this case, they may use a dedicated H.248 package for bearer technologies: the
35、Bearer Characteristics package (see clause A.3 of ITU-T Q.1950) defines a maximum of 255 different bearer types. This property BCP/BNCChar is actually synonym to termination type. In this case, the use of the TCM package does not provide information on the connection of bearer types. 4 Abbreviations
36、 and acronyms This Recommendation uses the following abbreviations and acronyms: AAL2 ATM Adaptation Layer 2 ALN Analog Line IP Internet Protocol MG Media Gateway MGC Media Gateway Controller RTP Real-time Transport Protocol TDM Time Division Multiplex 5 Conventions None. ITU-T Rec. H.248.51 (08/200
37、7) 3 6 Termination Connection Model Package Package Name: Termination Connection Model PackageID: tcm (0x00c6) Description: This package allows an MGC to audit a MG to determine the supported termination connection models. Version: 1 Extends: None 6.1 Properties 6.1.1 Supported Termination Connectio
38、ns Property Name: Supported Termination Connections PropertyID: stc (0x0001) Description: This root-only property describes the allowed termination configurations in a MG. Type: Sub-List of type String Possible values: The String is defined by the following H.248.1 Annex B ABNF: connectionConfig = L
39、BRKT configChoice *(COMMA configChoice) RBRKT ; at-most-once configChoice = topologyDescriptor / conferenceDescriptor / multicastDescriptor topologyDescriptor = TopologyToken LBRKT topologyTriple *(COMMA topologyTriple) RBRKT topologyTriple = terminationA COMMA terminationB COMMA topologyDirection C
40、OMMA eventStream topologyDirection = BothwayToken / IsolateToken / OnewayToken / OnewayExternalToken / OnewayBothToken conferenceDescriptor = ConferenceToken LBRKT conferenceDuple *(COMMA conferenceDuple) RBRKT conferenceDuple = terminationA COMMA UINT16 multicastDescriptor = MulticastToken LBRKT mu
41、lticastTriple *(COMMA multicastTriple) RBRKT multicastTriple = terminationA COMMA terminationB COMMA UINT16 terminationA = TerminationID LSBRKT instanceID RSBRKT terminationB = TerminationID LSBRKT instanceID RSBRKT instanceID = UINT16 ConferenceToken = (“Conference“ / “CNF“) MulticastToken = (“Mult
42、icast“ / “MLT“) NOTE Any elements not described in this ABNF are defined in Annex B of ITU-T H.248.1. Each instance of string in the “Sub-list of“ describes a single overall connection configuration, e.g., one connectionConfig. Default: None Defined in: TerminationState Characteristics: ReadOnly 6.1
43、.2 Non-Supported Termination Connections Property Name: Non-Supported Termination Connections PropertyID: nstc (0x0002) 4 ITU-T Rec. H.248.51 (08/2007) Description: This root-only property describes the termination configurations that are not allowed in a MG. Type: Sub-List of type String Possible v
44、alues: As per clause 6.1.1 Default: None Defined in: TerminationState Characteristics: ReadOnly 6.2 Events None. 6.3 Signals None. 6.4 Statistics None. 6.5 Error Codes None. 6.6 Procedures 6.6.1 Supported and Non-Supported Connections Normally the MG should be configured with the information of its
45、supported and/or non-supported termination connection configurations. To determine the supported configuration, a MGC may send an AuditValue command request to a MG that supports this package. The MGC should audit both the “Supported Termination Connections“ and the “Non-supported Termination Connec
46、tions“ properties. If the “Supported Termination Connections“ returns an empty result and the “Non-supported Termination Connections“ returns values by the MG in the reply, then ONLY the configurations in “Non-supported Termination Connections“ are non-supported by the MG, and the MGC may consider a
47、ny configuration other than those returned against “Non-supported Termination Connections“ is supported by the MG. If the “Supported Termination Connections“ returns values and the “Non-supported Termination Connections“ returns an empty result by the MG in the reply, then ONLY the configurations in
48、 “Supported Termination Connections“ are supported by the MG, and the MGC may consider any configuration other than those returned against “Supported Termination Connections“ is non-supported by the MG. If both the “Supported Termination Connections“ and “Non-supported Termination Connections“ are e
49、mpty in the reply, then the MGC is free to use any configuration. NOTE Practically speaking, this does not mean every conceivable configuration is possible. The MG may still return an error. If both the “Supported Termination Connections“ and “Non-supported Termination Connections“ return values in the reply, the same configuration shall not appear in both properties. The MGC should then only use the configurations listed in the “Supported Termination Connections“, and avoid using the configurations list
