1、 International Telecommunication Union ITU-T H.460.4 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2007) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services Supplementary services for multimedia Call priority designation and country/international network of call
2、 origination identification for H.323 priority calls ITU-T Recommendation H.460.4 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 synchroni
3、zation H.220H.229 Systems aspects H.230H.239 Communication procedures 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
4、Quality of service architecture for audiovisual and multimedia services 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
5、and services H.510H.519 Mobile multimedia collaboration applications 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
6、collaboration inter-working procedures H.560H.569 BROADBAND AND 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.460.4 (01/2007) i ITU-T Recommendation H.460.4 Call priority designa
7、tion and country/international network of call origination identification for H.323 priority calls Summary There is a desire to provide higher than normal priority call services to support several different applications. These applications include calls by authorized emergency personnel during disas
8、ter relief efforts, emergency calls by the public, or calls governed by service level agreements which specify a higher than normal probability of call completion. In order to provide these priority call services, it is necessary to signal to network elements such as Gatekeepers, Border Elements and
9、 Gateways that a call requires priority handling. This Recommendation defines messages and procedures necessary to signal the desired priority and country/international network of call origination for an H.323 priority call. Source ITU-T Recommendation H.460.4 was approved on 13 January 2007 by ITU-
10、T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. H.460.4 (01/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is
11、 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 Telecommunication Standardization Assembly (WTSA), which meets every four years,
12、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 some areas of information technology which fall within ITU-Ts purview, the necessar
13、y 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 recognized operating agency. Compliance with this Recommendation is voluntary. However, t
14、he 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 “shall“ or some other obligatory language such as “must“ and the negative equival
15、ents 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 the practice or implementation of this Recommendation may involve the use of a clai
16、med 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 approval of this Recommendation, ITU had n
17、ot received notice of 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/I
18、TU-T/ipr/. ITU 2007 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.460.4 (01/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 4 Abbreviations and acronyms 2 5 Call pri
19、ority and country/international network of call origination parameter definitions . 2 6 Messages and signalling. 5 7 Call priority procedures 6 7.1 Call priority and country/international network of call origination request during registration 6 7.2 Call priority and country/international network of
20、 call origination request during admission request 7 7.3 Call priority and country/international network of call origination request during call setup . 8 7.4 Call priority and country/international network of call origination request during location discovery . 9 7.5 Call priority and country/inter
21、national network of call origination indication during access request. 10 8 H.225.0 generic data usage. 11 8.1 Call Priority Designation feature and Country/International Network of Call Origination Identification feature tables. 12 8.2 Call Priority Designation parameter and Country/International N
22、etwork of Call Origination Identification parameter tables 12 Annex A Call Priority and Country/International Network of Call Origination Identification ASN.1 definitions for use inside Generic Data 14 A.1 Call Priority and Country/International Network of Call Origination Identification ASN.1 defin
23、itions 14 A.2 Description of New ASN.1 types and fields 15 ITU-T Rec. H.460.4 (01/2007) 1 ITU-T Recommendation H.460.4 Call priority designation and country/international network of call origination identification for H.323 priority calls 1 Scope This Recommendation specifies the call priority desig
24、nation and country/international network of call origination identification for H.323 priority calls. The use of the call priority designation provides a mechanism to indicate the desired or approved call establishment priority for an H.323 call. It is necessary to signal the call priority during re
25、gistration, admission, location, and call setup signalling in order for the Gatekeepers, Gateways, and other network elements to take appropriate action to attempt to assure the successful establishment of priority calls over normal traffic during times of degraded operation due to damaged resources
26、 or heavy loads. The use of country/international network of call origination identifies the country or the international network of priority call origination. It is necessary to signal the country/international network of call origination during registration, admission, location, and call setup sig
27、nalling in order for the Gatekeepers, Gateways, and other network elements to take appropriate action associated with the country or the international network of priority call origination. The H.323 systems compliant with the 2002 version of this Recommendation are not required to generate or proces
28、s the country/international network of call origination information. 2 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 v
29、alid. 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 Recommendations and other references listed below. A list of the currently valid ITU-T Recommendatio
30、ns 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. ITU-T E.106 ITU-T Recommendation E.106 (2003), International Emergency Preference Scheme (IEPS) for disaster relief operations. ITU-T E.164 I
31、TU-T Recommendation E.164 (2005), The international public telecommunication numbering plan. ITU-T H.225.0 ITU-T Recommendation H.225.0 Version 4 (2000), Call signalling protocols and media stream packetization for packet-based multimedia communication systems. ITU-T H.246 ITU-T Recommendation H.246
32、 (2006), Interworking of H-series multimedia terminals with H-series multimedia terminals and voice/voiceband terminals on GSTN, ISDN and PLMN. ITU-T H.323 ITU-T Recommendation H.323 Version 4 (2000), Packet-based multimedia communications systems. ITU-T H.460.1 ITU-T Recommendation H.460.1 (2002),
33、Guidelines for the use of the generic extensible framework. ITU-T H.501 ITU-T Recommendation H.501 (2002), Protocol for mobility management and intra/inter-domain communication in multimedia systems. 2 ITU-T Rec. H.460.4 (01/2007) ITU-T Q.931 ITU-T Recommendation Q.931 (1998), ISDN user-network inte
34、rface layer 3 specification for basic call control. ITU-T X.121 ITU-T Recommendation X.121 (2000), International numbering plan for public data networks. 3 Terms and definitions This Recommendation defines the following terms: 3.1 call priority: An indication of the importance of a call, as it relat
35、es to the probability of call completion and maintenance of call connection. 3.2 call completion: The ability to successfully make a call connection between a calling and called endpoint, assuming a called user is available to accept the call. 3.3 token: A piece of information, either clear or encry
36、pted, which can be used to validate a request for a specific call priority. 3.4 domain: A network or collection of networks under a single administrative authority that provides priority call establishment services. 3.5 country/international network of call origination: Information sent to identify
37、the country or the international network of call origination. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ACF Admission Confirmation ARQ Admission Request ASN.1 Abstract Syntax Notation One LCF Location Confirmation LRQ Location Request PDU Payload
38、 Data Unit PIN Personal Identification Number QoS Quality of Service RAS Registration, Admission and Status RCF Registration Confirmation RRQ Registration Request 5 Call priority and country/international network of call origination parameter definitions There are times when it is important to indic
39、ate the desired or required importance of a call. This may be due to service level agreements, emergency communications, or other system requirements. This importance, or call priority, is represented by a Call Priority Designation feature parameter that may be used to control those elements of the
40、network that affect the probability of call completion and minimize call loss. This is not used to specify the quality of the media streams, but pertains only to the completion of the call establishment process. Under normal circumstances, on a well-designed, lightly loaded network, this parameter m
41、ay have no apparent effect. However, in times of degraded operation, due to damaged resources or heavy loads, the parameter may allow for preferential treatment of certain call classes. ITU-T Rec. H.460.4 (01/2007) 3 Call priority is indicated by a priorityValue and an optional priorityExtension, wh
42、ich are described below. References to priority in the following clauses refer to this combination of priorityValue and priorityExtension. The country/international network of call origination can aid countries in establishing bilateral agreements with regard to the exchange of priority calls and th
43、e treatment of such calls. For example, the country/international network of call origination may have a multi-level preference scheme and may make an agreement with the country of call destination for this multi-level preference scheme to be mapped onto that of the country of destination. The count
44、ry/international network of call origination can aid in allowing administrations in making decisions to admit a priority call or to allow mapping of priority level between countries. The country/international network of call origination is represented by a Country/International Network of Call Origi
45、nation Identification feature parameter that may be used to identify the country or the international network of priority call origination. Country/international network of call origination is indicated by a numbering plan indicator, country code, and identification code (if needed), which are descr
46、ibed below. The priorityValue indicates a class of service that has a specific relative probability of call completion. Higher priority calls shall have a higher probability of call completion. The following table shows the relative priority of the different values. Value Priority emergencyAuthorize
47、d 0 Highest emergencyPublic 1 High 2 Normal 3 Lowest The Numbering plan indicator indicates the numbering plan used for the number. It is either according to ITU-T X.121 or to ITU-T E.164. A specific country of call origination is identified by a X.121 country code (3 digits). An international netwo
48、rk of call origination is identified by an E.164 country code for international networks (3 digits) and an identification code (1 to 4 digits). If new values are added, their relative priority shall be indicated in this clause. A domain is free to support and act on only a subset of the call priorit
49、yValues, or to treat multiple, adjacent values the same. A device receiving a priorityValue that is not supported within its domain, may respond by assigning a Normal priority to the call. The action to be taken by any device in response to a specified call priority is outside the scope of this Recommendation and is subject to the local policy of the domain. Any call that does not contain a Call Priority Designation feature parameter is assumed to be of Normal priority. The priorityExtension may be used to indicate sub-priorities within a gi
