1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T H.248.21TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2004) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: Semi-permanent connection handling package ITU-T Recomm
2、endation H.248.21 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 proce
3、dures 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 s
4、ervices 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 applicat
5、ions and 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.559 Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND AND
6、TRIPLE-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.248.21 (03/2004) i ITU-T Recommendation H.248.21 Gateway control protocol: Semi-permanent connection handling package Summary This R
7、ecommendation describes a package to enable the media gateway controller to indicate to the media gateway that terminations and the connection between the “semi-permanent“ marked terminations shall be treated as semi-permanent. Semi-permanent connections are defined and used by ITU-T Recs Q.931 and
8、X.31. Source ITU-T Recommendation H.248.21 was approved on 15 March 2004 by ITU-T Study Group 16 (2001-2004) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. H.248.21 (03/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field o
9、f telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World
10、Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the 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 so
11、me areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recogniz
12、ed operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain 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
13、“shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. 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 th
14、e practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation
15、development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are t
16、herefore strongly urged to consult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. H.248.21 (03/2004) iii CONTENTS Page 1 Scope 1 2 References. 2 3 Terms and definit
17、ions . 2 4 Abbreviations 2 5 Semi-permanent connection package . 2 5.1 Properties 3 5.2 Events . 3 5.3 Signals 3 5.4 Statistics 3 5.5 Procedures 3 ITU-T Rec. H.248.21 (03/2004) 1 ITU-T Recommendation H.248.21 Gateway control protocol: Semi-permanent connection handling package 1 Scope Semi-permanent
18、 connections are defined in ITU-T Recs Q.931 and X.31. ITU-T Rec. X.31 provides reference configurations for how semi-permanent connections are used. This Recommendation describes a package to enable the media gateway controller to indicate that terminations related to the ET, PH and/or AU devices a
19、nd the connection between them shall be subject to semi-permanent handling procedures by the MG. Figure 1 illustrates how a semi-permanent connection is used in a network. No call control signalling is shown since semi-permanent connections are initiated by a man-machine interface. Figure 1/H.248.21
20、 Semi-permanent connection use This Recommendation describes the use of semi-permanent connections with ISDN networks and covers both types of semi-permanent connections defined in ITU-T Rec. Q.931: 1) Physical layer semi-permanently established between the terminal and the PH/AU; 2) X.25 data link
21、and physical layers semi-permanently established between the terminal and the PH/AU. The semi-permanent connection handling package may be used whenever the behaviour described in the procedures section of the package is required. 2 ITU-T Rec. H.248.21 (03/2004) 2 References The following ITU-T Reco
22、mmendations and other references 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 t
23、herefore 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. The reference to a document within this Recommendation does not give it, as a s
24、tand-alone document, the status of a Recommendation ITU-T Recommendation H.248.1 (2002), Gateway control protocol: Version 2. ITU-T Recommendation Q.931 (1998), ISDN user-network interface layer 3 specification for basic call control. ITU-T Recommendation X.25 (1996), Interface between Data Terminal
25、 Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit. ITU-T Recommendation X.31 (1995), Support of packet mode terminal equipment by an ISDN. 3 Terms and definitions None. 4 Abbreviations T
26、his Recommendation uses the following abbreviations: AU Access Unit DTE Data Terminal Equipment ET Exchange Termination ISDN Integrated Services Digital Network MG Media Gateway MGC Media Gateway Controller NT Network Termination PH Packet Handler PSPDN Packet Switched Public Data Network TA Termina
27、l Adaptor TE Terminal Equipment 5 Semi-permanent connection package Package Name: Semi-permanent connection handling PackageID: semper, 0x006a Description: This package defines a property and procedures that are used on semi-permanently marked terminations. Version: 1 ITU-T Rec. H.248.21 (03/2004) 3
28、 Designed to be extended only: No Extends: None 5.1 Properties 5.1.1 Property Name: Activate semi-permanent connection PropertyID: act, 0x0001 Description: The value of this property indicates if the termination is requested to be part of a semi-permanent connection. Type: Boolean Possible values: “
29、on“ (TRUE) Receive semi-permanent handling “off“ (FALSE) Semi-permanent handling not utilized Default Defined in: Termination State Descriptor Characteristics: Read/Write 5.2 Events None. 5.3 Signals None. 5.4 Statistics None. 5.5 Procedures 5.5.1 Semi-permanent termination establishment/modificatio
30、n When the MGC determines (via man-machine command or other provisioning) that a semi-permanent connection is required, an Add/Modify/Move command will be sent to the appropriate termination(s) with the semper/act property set to “on“ (semi-permanent handling). The request shall contain an explicit
31、TerminationID (i.e., no wildcarding, except for CHOOSE in an Add command) for the termination that MG will initiate the appropriate semi-permanent handling on. 5.5.2 Semi-permanent termination behaviour If a MGC issues commands using wildcarded TerminationID (with “*“ or “ALL“), no action shall be t
32、aken on termination(s) that have the semper/act property set to “on“. If the wildcarded TerminationID only matches TerminationIDs with the semper/act property set to “on“, then the MG shall return error 431, “No TerminationID matched a wildcard“. For example: When a global Subtract (ContextId ALL, T
33、erminationId ALL) is issued from the MGC, existing terminations with semi-permanent handling requested will not be affected. This behaviour applies for all commands, apart from AuditValue and AuditCapabilities. An individual AuditValue on the semper/act property explicitly identifies a semi-permanen
34、t termination even if the ContextId and/or the TerminationID are wildcarded. This allows the MGC to determine which terminations are semi-permanently marked even if it has suffered a failure and has lost state information without auditing every termination on the MG. 4 ITU-T Rec. H.248.21 (03/2004)
35、NOTE Individual auditing is not supported by ITU-T Rec. H.248.1 Version 1 (03/2002). 5.5.3 Semi-permanent termination removal When a MGC requires a semi-permanent termination/connection to be removed, a Subtract command will be sent with the appropriate TerminationID(s) explicitly specified. If the
36、MGC requires that semi-permanent termination/connection handling be stopped, then a Modify or Move command explicitly identifying the appropriate TerminationID shall be issued with semper/act = off. Printed in Switzerland Geneva, 2004 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work
37、 of ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunication statistics Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services S
38、eries G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference
39、Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Series N Maintenance: international sound programme and television
40、transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic
41、 services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure, Internet protocol aspects and Next Generation Networks Series Z Languages and general software aspects for telecommunication systems
