1、INTERNATIONAL TELECOMMUN CATION UN ION ITU-T TELECOMMUNICATION STAN DARD IZAT ION SECTOR OF ITU (07200 1 ) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services - Communication procedures - Gateway control protocol: H.248.1 packages for H.323 and H.324 interworking ITU-
2、T Recommendation H.248.12 ITU-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS INFRASTRUCTURE OF AUDIOVISUAL SERVICES General Transmission multiplexing and synchronization H. 100-H. 199 H.200-H.219 H.22-H.229 H.230-H.239 7x_1 IX Systems aspect
3、s -I_. I O-E259 -I ommunicatin -_- - A procedures _ - _i - i Coding of moving video H.260-H.279 Related systems aspects SYSTEMS AND TERMINAL EQUIPMENT FOR AUDIOVISUAL SERVICES SUPPLEMENTARY SERVICES FOR MULTIMEDIA MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definiti
4、ons, protocols and procedures Mobility for H-Series multimedia systems and services Mobile multimedia collaboration applications and services Security for mobile multimedia systems and services Security for mobile multimedia collaboration applications and services Mobility intenvorking procedures Mo
5、bile multimedia collaboration inter-working procedures H.280-H.299 H.300-H.399 H.450-H.499 H.500-H.509 H.5 1 O-H.5 19 H.520-H.529 H.530-H.539 H.540-H.549 H.550-H.559 H.560-H.569 For further details, please refer to the list of ITU-T Recommendations. ITU-T Recommendation H.248.12 Gateway control prot
6、ocol: H.248.1 packages for H.323 and H.324 interworking Summary This Recommendation defines several H.248.1 packages that are intended for Media Gateways designed to support interworking between H.323 terminals and H.324 terminals. More specifically, this Recommendation contains: package “h324“ for
7、creating terminations supporting H.324, package “h245“ for creating terminations supporting H.245 channels for H.324 calls, package “h323bc“ for creating terminations supporting H.245 channels for H.323 calls, package “h245comll for the communication of H.245 commands between a MGC and MG, and packa
8、ge “h245ind“ for the communication of H.245 indications. NOTE - This Recommendation has been renumbered. It was formerly known as ITU-T Rec. H.248, Annex M4. Source ITU-T Recommendation H.248.12 was prepared by ITU-T Study Group 16 (2001-2004) and approved under the WTSA Resolution 1 procedure on 29
9、 July 200 1. ITU-T Rec. H.248.12 (07/2001) 1 FOREWORD The International Telecommunication Union (ITLJ) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying
10、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 the ITU-T study groups wh
11、ich, 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 collaborative basis with IS0 an
12、d IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommend
13、ation 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 development process. As of the date of approva
14、l 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 therefore strongly urged to consult the TSB pat
15、ent database. o ITU 2002 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of JTU. 11 ITU-T Rec. H.248.12 (07/2001) CONTENTS 1 Introduction . 2 Scope . 3 References . 3.1 Normative references 3.2 Informative reference .
16、4 H324 package . 4.1 4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 4.1.6 4.2 4.3 4.4 4.4.1 4.4.2 4.4.3 4.5 Properties Communication mode Highest Multiplexing Level Demultiplex Incoming Multiplex Table Outgoing Multiplex Table Signals Remote H.223 capability Events . Statistics MUXPDU sent . MUXPDU received MUXPDU e
17、rror Procedures 5 H245 Package . 5.1 Properties 5.1.1 H.245 channel state . 5.1.2 Terminal Type 5.2 Events . 5.2.1 H245 Message 5.2.2 H.245 Channel Closed 5.3 Signals 5.4 Statistics 5.5 Procedures 6 H323 Bearer Control Package 6.1 Properties 6.1.2 H.245 Message Encapsulation 6.1.1 Fast Connect . 6.2
18、 Events . Page 1 1 1 1 2 2 3 3 3 4 4 5 5 5 6 6 6 6 6 6 7 7 7 7 8 8 11 11 11 11 11 11 11 12 12 . ITU-T Rec . H.248.12 (07/2001) 111 6.3 Signals . ; 6.4 Statistics 6.5 Procedures 7 H.245 Command Package 7.1 Properties 7.1.1 Incoming MiscellaneousCommand 7.1.2 Outgoing Miscellaneous Command . 7.1.3 Inc
19、oming H223MultiplexReconfiguration Command 7.1.4 Outgoing H223MultiplexReconfiguration Command 7.2 7.3 Signals : 7.4 Statistics 7.5 Procedures Events . . 8 H.245 Indication package : 8.1 Properties 8.1.1 Incoming MiscellaneousIndication . 8.1.2 Outgoing MiscellaneousIndication . 8.2 Signals 8.3 8.4
20、Statistics Events . 8.5 Procedures 9 Call flows H.323-Annex CH.324 intenvorking with H.245 in MG . Calls with origination by the Annex CH.324 side . Calls with origination by the H.323 side H.323-Annex CH.324 intenvorking with H.245 in MGC . Tunnelling of Annex CH.324 bitstream 9.1 9.1.1 9.1.2 9.2 9
21、.3 Page 12 12 12 13 13 13 14 14 14 15 15 15 15 15 15 15 16 16 16 16 16 16 16 16 18 19 21 iv ITU-T Rec . H.248.12 (07/2001) ITU-T Recommendation H.248.12 Gateway control protocol: H.248.1 packages for H.323 and H.324 interworking 1 Introduction This Recommendation gathers packages for H.245, H.245 pa
22、rameters specific to H-series audiovisual terminals, and Annex Cm.324 terminals for use with the H.248.1 gateway control protocol. The packages in this Recommendation are in conformance with clause 12m.248.1 package definition guidelines. 2 Scope This Recommendation describes packages for the H.248.
23、1 gateway control protocol related to interworking of H.323 and H.324 terminals, as follows: - - - - Package “h324“ for termination of H.324 bitstream on MGs. Package “h245“ for termination of H.245 messages on MGs. Package “h323bc“ for H.245 parameters specific to H.323. Package “h245com“ for provi
24、ding properties that allow the MGC to indicate to the MG that the MGC has sent or received an H.245 command. Package “h245ind“ for providing properties that allow the MGC to indicate to the MG that the MGC has sent or received an H.245 indication. - With the terminations implementing “h324“, %245com
25、“ and “h245ind“ packages, the decomposed gateway may support H.324 communication with the H.245 control function in the MGC. In the H.324 and H.323 interworking scenario with this decomposed gateway, H.245 control messages are terminated in the MGC (a backhaul is used between the MG and the MGC to t
26、ransport H.245 messages between the MG and the MGC, on the H.324 side). The terminations for media on both H.324 and H.323 sides are managed by the MGC. With the terminations implementing “h324“ and %245“ packages, the decomposed gateway may support H.324 communication with H.245 control in the MG.
27、In the H.324 and H.323 interworking scenario with this decomposed gateway, H.245 control messages from the H.324 side and the H.323 side are terminated in the “h245“ termination and in the “h323bc“ termination respectively, and are processed in the MG. The MG manages the logical channels for media.
28、3 References The following ITU-T Recommendations 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 revisio
29、n; users of this Recommendation 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. 3.1 Normative references - ITU-T Recommend
30、ation H.223 (200 1 ), Multiplexingprotocol for low bit rate multimedia communication. ITU-T Recommendation H.245 (200 i), Control protocol for multimedia communication. - ITU-T Re this is allowed in the sub- list. The MG should ignore all the other elements in the sub-list if “none“ is present. If “
31、none It is not present, but “all“ is present, the MG should ignore all other elements in the sub-list. The MG should also ignore all elements that specify individual H.245 Request messages, if the element “Req“ is present in the sub-list. The same is true with the presence of “Res“, “Com1 or “Ind“,
32、wherein the MG should ignore elements specifjing individual H.245 Responses, Commands or Indications. Support for the event notification of commands is optional. Support for the event notification of the EndSession command is recommended in order to ensure smooth call release. ObservedEventsDescript
33、or Parameters: Parameter Name: Contents of H.245 message detected ParameterID : h245mc (0x0002) Type: OCTET STRING Description: Specifies the actual contents of the H.245 message detected by the MG. The octet string is the actual X.691 encoding received by the MG. 10 ITU-T Rec. H.248.12 (07/2001) 5.
34、2.2 H.245 Channel Closed Event Name: H.245 Channel Closed Event ID : h245ChC (0x0002) Description: This event occurs when the MG completes the closing of a H.245 channel. EventsDescriptor Parameters: None. ObservedEventsDescriptor Parameters: None. 5.3 Signals None. 5.4 Statistics None. 5.5 Procedur
35、es This package may be used on terminations that carry H.245 information, if the MGC wants to process this information on the MG. The MGC may ask the MG for notification on detecting a particular type of H.245 message on the h245 termination. The MGC shall set the “cs“ (Channel State) property to tr
36、ue initially. When the MGC wants MG to close the H.245 channel it shall mod$ the value of the “CS“ property to “FALSE“.The MG shall follow the procedures defined in Annex Fm.246 to close the H.245 channel. 6 H323 Bearer Control Package Package Name: H.323 Bearer Control PackageID : h323bc, (Ox002b)
37、Version: 1 Extends: h245 Package version 1 (defined in this Recommendation) Description: This package specifies an extension t the h245 Package to support H.323 fast start and the H.323 use of H.245 tunnelling. This package shall be implemented only if the MG supports H.323 communication where the H
38、.245 control function is in the MG. This package shall not be used for H.323 communication where the H.245 control is in the MGC. 6.1 Properties 6.1.1 Fast Connect Property ID : Type: Enumer at ion Possible values: fastconnect (Ox000 1) noFastStart fastStart (0x0001) MGC using separate H.245 channel
39、 or using H.245 tunnelling (0x0002) Only fastStart procedures are being used, no parallel H.245control ITU-T Rec. H.248.12 (07/2001) II parallelH245 (0x0003) Parallel H.245 control is supported Defined in: LocalControl Characteristics: Readwrite Description: This property specifies if the fast conne
40、ct procedure is used. If the MGC rejects or does not initiate the fast connect procedure, this field shall contain “noFastStart“. This property indicates to the MG that the MGC has decided to use H.245 tunnelling or a separate channel for H.245 to the H.323 endpoint. If the MGC accepts or initiates
41、a request for the fast connect procedure, this field shall be set to “fastStart“. If however the MGC also decides to support the parallel H.245 procedures along with fast connect, this field shall be set to “parallelH245“. The default value for this property shall be “noFastStart“. 6.1.2 H.245 Messa
42、ge Encapsulation Property ID : h245encapstatus (0x0002) Type: Boolean Possible values: FALSE (0x0000) H.245 message encapsulation is disabled TRUE (Ox000 1) H.245 message encapsulation is enabled Defined in: LocalControl Characteristics: Readwrite Description: This property specifies whether H.245 m
43、essage encapsulation is enabled or not enabled on the connection to the H.323 endpoint. Practically this property reflects the value of h245Tunneling element in the H.225 .O messages. The default value shall be FALSE. 6.2 Events Event Name: Event ID: sepH245 (0x0001) Description: Switch to separate
44、H.245 channel The MG shall noti the MGC with this event when the MG requires the opening of a separate H.245 channel to the H.323 endpoint. This typically happens in a case where the call was set-up using fastStart procedures and the H.245 message tunnelling was disabled. The MGC shall ignore this e
45、vent if a separate H.245 channel is already open to the H.323 endpoint. 6.3 Signals None. - 6.4 Statistics None. 6.5 . Procedures This package supports various ways to start H.245 procedures as specified in 8.2H.323. The termination that realizes this package shall be made if and only if the process
46、ing of H.245 messages 12 ITU-T Rec. H.248.12 (07/2001) fi-om the H.323 side of the gateway is to be performed in the MG. In the following description, it is premised that the MGC requests the creation of the termination that terminates H.245 control. The MGC that decides to utilize H.245 tunnelling
47、or initiates a separate H.245 channel with the H.323 side, shall generate the termination with the fastconnect property set to the value “noFastStart“ . The MGC that decides to use the fast connect procedure shall request the creation of a termination that has the value of the fastconnect property s
48、et to other than “noFastStart“ according to the procedure to be taken. If the MGC decides to use H.245 tunnelling or fast connect procedures (with or without parallelH245), H.245 messages shall terminate at the MGC and the MGC shall be responsible for redirecting H.245 messages to the H323bc termina
49、tion at the MG. The MGC can implement this H.245 message redirection by using one of its own addresses as the remote address of the h323bc termination when this is created. The MGC shall indicate a switch to a separate H.245 channel by changing the value of the fastconnect property from “fastStart“ or “parallelH245“ to “noFastStart“, and the value of h245encapstahis property to FALSE (using a MODIFY command). The MGC should not MODIFY the value of the fastconnect property to “fastStart“ or “parallelH245“ fi-om IhoFastStart“ if the MG has already received a message on
