1、 International Telecommunication Union ITU-T H.460.6TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2013) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Supplementary services for multimedia Extended Fast Connect feature Recommendation ITU-T H.460.6 ITU-T H-SE
2、RIES 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 H.240H.259 Coding of m
3、oving 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 services H.360H.369 Supplemen
4、tary services for multimedia H.450H.499MOBILITY 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 and services H.520H.529
5、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, TRIPLE-PLAY AND ADVANCED MULTIME
6、DIA SERVICES Broadband multimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 Ubiquitous sensor network applications and Internet of Things H.640H.649 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700H.719 IPTV terminal devices H.720H
7、.729 IPTV middleware H.730H.739 IPTV application event handling H.740H.749 IPTV metadata H.750H.759 IPTV multimedia application frameworks H.760H.769 IPTV service discovery up to consumption H.770H.779 Digital Signage H.780H.789 For further details, please refer to the list of ITU-T Recommendations.
8、 Rec. ITU-T H.460.6 (03/2013) i Recommendation ITU-T H.460.6 Extended Fast Connect feature Summary Recommendation ITU-T H.460.6 provides a method for the rapid creation or reconfiguration of media streams under the control of endpoints or third parties. It is especially useful for operations such as
9、 the redirection of a caller to an automatic voice response unit, or the initiation of new media channels, such as a modem data channel, in response to detected events, such as modem answer tone. It also supports the rapid redirection of media streams from a called party to an automatic answering de
10、vice. This revision introduces a number of corrections and clarifications by incorporating technical and editorial corrections from the ITU-T H.323-series Implementers Guide (03/2011). History Edition Recommendation Approval Study Group 1.0 ITU-T H.460.6 2002-11-29 16 2.0 ITU-T H.460.6 2013-03-16 16
11、 ii Rec. ITU-T H.460.6 (03/2013) FOREWORD 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 I
12、TU. 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 Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics
13、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 some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepare
14、d 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 recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may c
15、ontain 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 “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to expr
16、ess 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 the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Prop
17、erty 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 approval of this Recommendation, ITU had not received notice of
18、 intellectual property, 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 2013 A
19、ll rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T H.460.6 (03/2013) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions and acronyms . 2 3.1 Abbreviations and acronyms 2 3.2 Definitions 2
20、 4 Overview 3 4.1 Negotiation of Extended Fast Connect . 3 4.2 Invocation of Extended Fast Connect . 5 4.3 Opening new sessions . 7 4.4 Closing open channels 7 4.5 Terminating available sessions . 8 4.6 Conflict resolution 8 4.7 Channel redirection and media session reconfiguration . 9 4.8 Media enc
21、ryption 10 4.9 Requesting new channel proposals . 10 4.10 EFC request sequencing . 10 4.11 EFC counter proposals . 11 4.12 Moving to ITU-T H.245 logical channel procedures . 11 4.13 Failure conditions . 12 5 Interaction with existing procedures . 12 5.1 Fast Connect . 12 5.2 UserInputIndication 12 5
22、.3 EndSession command . 12 5.4 Simple Endpoint Type (SET) . 12 5.5 EFC third-party pause and rerouting 13 Rec. ITU-T H.460.6 (03/2013) 1 Recommendation ITU-T H.460.6 Extended Fast Connect feature 1 Scope Seamless operation of IP telephony requires the ability to initiate, redirect and reconfigure me
23、dia connections in a fast and efficient manner. The reduction of “dead time“ and quick response to user actions both demand that media operations be carried out as quickly as possible. For example, a caller might be redirected from an endpoint that does not answer to a voice messaging endpoint that
24、answers automatically. A call may suspend media transfer when a user invokes “hold“, then should re-establish media transfer quickly when the user re-joins the call. Similarly, media connections should be quickly reconfigured when a user activates a conference or is switched to an automatic announce
25、ment. Such capabilities are available to the simple endpoint type (SET) as described in Annex F of ITU-T H.323. This Recommendation provides a method by which an endpoint may negotiate the capability to initiate, rearrange, reconfigure, or close one or more media channels as efficiently and quickly
26、as a SET using the repeated Fast Connect procedures. The advantages of this method, relative to ITU-T H.245 include: the ability of one party to initiate creation of both transmit and receive media channels (not strictly possible in ITU-T H.245 since the ModeRequest cannot specify a capability, nor
27、can it specify replacementFor); the ability of two parties to establish media channels with a single exchange of messages (ITU-T H.245 requires a three-way to five-way exchange); the ability of one party to close a media channel with a single message (ITU-T H.245 requires two or three messages); the
28、 ability of one party to redirect a media channel with a single message (ITU-T H.245 requires at least three); optional use of tunnelled ITU-T H.245 to provide capability exchange, master/slave negotiation and non-media controls such as user input indication. The generic extensible framework (GEF) o
29、f ITU-T H.225.0 is used to negotiate the use of Extended Fast Connect (EFC) procedures. This negotiation may proceed in parallel with tunnelled ITU-T H.245 capability negotiation via the parallelH245Control tunnel and/or standard Fast Connect establishment of one or more initial media channels, as d
30、escribed below. The term “party“ is used herein to refer to either an endpoint or a gatekeeper actively involved in call signalling and media control with another party. The EFC feature may be invoked between endpoints (direct-routed calls or relayed via a gatekeeper), or may involve one or more act
31、ive gatekeepers or call feature servers. The term “third party“ is used to indicate an active party that is not the source or recipient of a media channel. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provi
32、sions 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 investigate the possibility of applying the most recent edition of the Recommendatio
33、ns 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 of a Recommendation. 2 Rec. ITU-T H.460.6 (03/2013) ITU-T H.225.0 Recommend
34、ation ITU-T H.225.0 (2009), Call signalling protocols and media stream packetization for packet-based multimedia communications systems. ITU-T H.245 Recommendation ITU-T H.245 (2011), Control protocol for multimedia communication. ITU-T H.323 Recommendation ITU-T H.323 (2009), Packet-based multimedi
35、a communication systems. ITU-T H.460.1 Recommendation ITU-T H.460.1 (2013), Guidelines for the use of the generic extensible framework. 3 Definitions and acronyms This Recommendation uses the following terms, abbreviations and acronyms: 3.1 Abbreviations and acronyms EFC Extended Fast Connect OLC IT
36、U-T H.245 OpenLogicalChannel element SET Simple Endpoint Type (described in Annex F of ITU-T H.323) 3.2 Definitions This Recommendation defines the following terms: 3.2.1 acceptance fastStart: A fastStart element which represents an acceptance of a proposed media session. Each OLC within the accepta
37、nce fastStart element accepts one of the proposed channels, and is formatted as specified in clause 8.1.7 of ITU-T H.323. The acceptance fastStart may also be used to reconfigure a session. In this Recommendation, the term “fastStart“ (in boldface) without qualification will denote an acceptance fas
38、tStart. 3.2.2 acceptance null-OLC: A null-OLC within an acceptance fastStart. This OLC is used to close (halt media transmission on) an open channel. The associated session remains available for use. 3.2.3 available session: Any media session that has been proposed, whether or not one or more channe
39、ls of the session have been opened by an acceptance. A session may be cancelled, in which case it ceases to exist and may no longer be used. 3.2.4 idle channel: A channel over which media transmission has been halted via a Null-OLC. 3.2.5 null-OLC: OLC element specifying nullData and no transport ad
40、dresses. 3.2.6 open channel: A media channel that is established for media transmission. 3.2.7 party: Endpoint or gatekeeper involved in call signalling and media control. 3.2.8 proposal fastStart: A fastStart element proposing new media channels for a session. The form of each offer OLC within the
41、fastStart is specified in clause 8.1.7 (Fast Connect Procedures) of ITU-T H.323. EFC provides an explicit indication that a fastStart element represents a session proposal, and the OLCs therein should be interpreted as channel proposals. 3.2.9 proposal null-OLC: A null-OLC within a proposal fastStar
42、t. This OLC is used to cancel an available session. The session ceases to exit. Rec. ITU-T H.460.6 (03/2013) 3 4 Overview This feature is based on repeated use of Fast Connect procedures using fastStart elements in ITU-T H.225.0 messages in the manner similar to that described for simple endpoint ty
43、pes in Annex F of ITU-T H.323, but extends those capabilities to other endpoints and gatekeepers, and other media types, including encrypted media. If a party wishes to open one or more media channels at any time during a call, it may request them by sending any valid message with a fastStart elemen
44、t describing the channel(s). The other party may accept (or reject) the proposals by returning a corresponding fastStart element. Simple mechanisms are provided to permit a party to close channels or redirect them. The efficiency and compactness of the messaging can be enhanced through use of the IT
45、U-T H.245 signalling tunnel to exchange media capabilities beyond those included in the initial fast connect proposal. 4.1 Negotiation of Extended Fast Connect Extended Fast Connect (EFC) will be negotiated as a generic extensible feature (GEF) as described in ITU-T H.323. The FeatureDescriptor for
46、Extended Fast Connect in Table 1 will be a GenericData element with a standard GenericIdentifier of value “6“: Table 1 Extended Fast Connect feature Feature name: Extended Fast Connect (EFC) Feature description: This feature permits the use of fastStart elements to establish and reconfigure media ch
47、annels in the manner established for SETs in Annex F of ITU-T H.323. Feature identifier type: Standard Feature identifier value: 6 The following sub-feature parameters are defined for EFC. The EFC Proposal sub-feature of clause 4.1.1 shall be supported as part of EFC; support for the others is optio
48、nal and shall be negotiated by listing the feature identifiers as parameters to the EFC entry or entries in the appropriate generic extensibility feature negotiation fields. The parameters are used within a genericData list in ITU-T H.225.0 call signalling messages in order to indicate or invoke the
49、 corresponding feature/request. 4.1.1 Media channel proposals This parameter is defined in Table 2 and shall be used by an endpoint or a third party to indicate that the fastStart element within the present message contains channel proposals for one or more new media sessions. Support for this parameter is required for EFC and need not be included during negotiation of EFC support. Table 2 EFC Proposal parameter Parameter name: EFC Proposal Parameter description: The presence of this parameter indicates
