1、 International Telecommunication Union ITU-T J.263TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2009) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS IPCablecom Specification for priority in preferential telecommunications over IPCablecom2
2、networks Recommendation ITU-T J.263 Rec. ITU-T J.263 (10/2009) i Recommendation ITU-T J.263 Specification for priority in preferential telecommunications over IPCablecom2 networks Summary Recommendation ITU-T J.263 is one of a series of Recommendations to enable support for preferential telecommunic
3、ation services over IPCablecom2 networks. It defines the specifications for priority for preferential telecommunication services over IPCablecom2 networks. These specifications satisfy the requirements defined in Recommendation ITU-T J.260. The essential aspects of preferential telecommunications ov
4、er IPCablecom2 can be grouped into two areas: prioritization and authentication. This Recommendation provides specifications for prioritization only. Prioritization may be utilized for premium services and for emergency services in IPCablecom2 that may require preferential treatment (e.g., telecommu
5、nications for disaster relief and the emergency telecommunications service). The implementation of priority and authentication is necessary for the support of preferential telecommunications services in IPCablecom networks. This Recommendation only covers technical aspects for achieving prioritized
6、treatment in IPCablecom2 networks. Source Recommendation ITU-T J.263 was approved on 30 October 2009 by ITU-T Study Group 9 (2009-2012) under the WTSA Resolution 1 procedure. ii Rec. ITU-T J.263 (10/2009) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agen
7、cy 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 responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view
8、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 which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendatio
9、ns 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 ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for concisenes
10、s to indicate both a telecommunication administration and a recognized 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 i
11、s 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. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELL
12、ECTUAL 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 takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whe
13、ther 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 property, protected by patents, which may be required to implement this Recommendation. However, implementers are c
14、autioned 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 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission
15、of ITU. Rec. ITU-T J.263 (10/2009) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 4 Abbreviations and acronyms 2 5 Conventions 2 6 Priority in IPCablecom2 . 3 6.1 Priority signalling in IPCablecom2 3 6.2 Priority-enabling mechanisms in IPCablecom2 . 3 7 Req
16、uirements for signalling priority in IPCablecom2 11 7.1 Requirements using option 1 11 7.2 Requirements using option 2 12 8 Requirements for the priority enabling mechanism in IPCablecom2 . 12 8.1 SIP UA and CM 12 8.2 CMTS . 12 8.3 PCRF 13 8.4 P-CSCF . 14 8.5 Preferential Treatment-AS (PrefTreat-AS)
17、 14 Annex A Namespace used for ITU Region A 15 Annex B Namespace used for ITU Region B . 15 Annex C Namespace used for ITU Region C . 15 Annex D Namespace used for ITU Region D 15 Annex E Namespace used for ITU Region E . 16 Appendix I Example of use of the R-P header 17 Bibliography. 18 iv Rec. ITU
18、-T J.263 (10/2009) Introduction Emergency and disaster communications for authorized users plays a vital role in the health, safety, and welfare of people in all countries. The common thread to facilitate emergency/disaster operations is the utility of assured capabilities for user-friendly preferen
19、tial telecommunication services that may be realized by technical solutions and/or administrative policy. The IPCablecom2 infrastructure offers an important resource for assured emergency/disaster telecommunications. Emergency and disaster situations can impact telecommunication infrastructures. Typ
20、ical impacts may include congestion overload and the need to re-deploy or extend communications capabilities beyond that covered by existing infrastructures. Even when telecommunications infrastructures are not damaged by these situations, demand for telecommunication resources soar during such even
21、ts. Therefore, priority mechanisms are needed so that limited bandwidth resources can be allocated to authorized emergency workers during emergency and disaster situations. Generally, when prioritized or preferential treatment of telecommunication capabilities are offered, users of the associated se
22、rvice or services will be authenticated and authorized. Whether authentication and authorization are required or not is a national decision. However, without authentication and authorization, preferential treatment capabilities may be subject to abuse by non-authorized individuals. This Recommendati
23、on provides specifications stemming from the requirements of ITU-T J.260 for mechanisms to provide priority in IPCablecom2 networks in support of preferential/prioritized treatment to services that need or benefit from such treatment. Rec. ITU-T J.263 (10/2009) 1 Recommendation ITU-T J.263 Specifica
24、tion for priority in preferential telecommunications over IPCablecom2 networks 1 Scope This Recommendation is one of a series of Recommendations to enable support for preferential telecommunication services over IPCablecom networks. These specifications do not apply to ordinary emergency calls such
25、as people calling the police, the fire department, ambulances, etc. Aspects of preferential telecommunications include provisions for authentication and priority (special handling). The objective of this Recommendation is to provide an initial set of priority specifications for preferential telecomm
26、unications within IPCablecom2 networks according to the framework described in ITU-T J.261. This Recommendation defines two options for introducing the priority header during signalling. This Recommendation defines specifications for capabilities which, when implemented, should help support preferen
27、tial telecommunication services. NOTE Pre-emption specifications and authorization specifications are outside the scope of this Recommendation and are considered to be national matters. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference
28、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 investigate the possibility of applying the most recen
29、t 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 of a Recommendation. ITU-T J.179 Recommendati
30、on ITU-T J.179 (2004), IPCablecom support for multimedia. ITU-T J.260 Recommendation ITU-T J.260 (2005), Requirements for preferential telecommunications over IPCablecom networks. ITU-T J.261 Recommendation ITU-T J.261 (2009), Framework for implementing preferential telecommunications in IPCablecom
31、and IPCablecom2 networks. IETF RFC 4412 IETF RFC 4412 (2006), Communications Resource Priority for the Session Initiation Protocol (SIP). 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 assured capabilities ITU-T J.260: Capabilities pro
32、viding high confidence or certainty that critical telecommunications are available and perform reliably. 3.1.2 authentication ITU-T J.260: The act or method used to verify a claimed identity. 3.1.3 authorization ITU-T J.260: The act of determining if a particular privilege, such as access to telecom
33、munications resources, can be granted to the presenter of a particular credential. 2 Rec. ITU-T J.263 (10/2009) 3.1.4 emergency situation ITU-T J.260: A situation, of serious nature, that develops suddenly and unexpectedly. Extensive immediate important efforts, facilitated by telecommunications, ma
34、y be required to restore a state of normality to avoid further risk to people or property. If this situation escalates, it may become a crisis and/or disaster. 3.1.5 international emergency situation ITU-T J.260: An emergency situation, across international boundaries, that affects more than one cou
35、ntry. 3.1.6 label ITU-T J.260: An identifier occurring within or attached to data elements. In the context of preferential telecommunications it is an indication of priority. This identifier can be used as a mapping mechanism between different network priority levels. 3.1.7 policy ITU-T J.260: Rules
36、 (or methods) for allocating telecommunications network resources among types of traffic that may be differentiated by labels. 3.1.8 preferential ITU-T J.260: A capability offering advantage over regular capabilities. 3.1.9 priority treatment capabilities ITU-T J.260: Capabilities that provide premi
37、um access to, and/or use of telecommunications network resources. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations: CM Cable Modem CMTS Cable Modem Termination System COPS Common Open Policy Service (defined in b-IETF RFC 2748) CSCF Call Session Control Function DSA
38、Dynamic Service Add DSCP Differentiated Services Code Point MTA Media Terminal Adapter P-CSCF Proxy Call Session Control Function PCRF Policy Control and Charging Rules Function PIN Personal Identification Number PRACK Provisional Response ACKnowledgement PSTN Public Switched Telephone Network R-P R
39、esource Priority RTP Real-time Transport Protocol UA User Agent 5 Conventions None. Rec. ITU-T J.263 (10/2009) 3 6 Priority in IPCablecom2 Prioritization entails obtaining a higher probability for completing a call or session. This capability should exist on the access link and it must also be propa
40、gated throughout all relevant network entities to provide, as much as possible, end-to-end preferential treatment. The framework Recommendation ITU-T J.261 defines three aspects related to priority: the labelling, signalling and enabling mechanisms. The following clauses contain the specifications f
41、or the signalling and an enabling mechanism. As stated in the framework, placing the priority label in the data packets transmitted using RTP is not available. As a result, this Recommendation addresses only the requirements for signalling and enabling mechanisms. Several alternative methods are def
42、ined, which include the following: defining a new per hop behaviour for preferential traffic, a new shim layer protocol over IP, marking an application layer packet, and allocating a Diffserv code point, MPLS label, Ethernet Class of Service or other priority markings to label the packets associated
43、 with particular messages. 6.1 Priority signalling in IPCablecom2 The framework identifies the use of Resource-Priority and Accept-Resource-Priority headers defined in IETF RFC 4412 to signal the priority in SIP request and response messages. IETF RFC 4412 defines the term RP actor. This term refers
44、 to all entities that act upon the Resource-Priority header. These entities are the SIP proxies and the SIP user agents (UAs). In IPCablecom2, the SIP proxies are collectively called CSCF (call session control function). The UAs are the end points that initiate and receive a session: they are respec
45、tively the SIP UAC (user agent client) and SIP UAS (user agent server). These will both be referred to as the SIP UA. There are two options for handling the R-P header. In the first option, the SIP UA shall include the R-P header, as described in section 4.7.1 of IETF RFC 4412, in the request messag
46、es when requesting sessions in support of preferential telecommunication services. In the second option, a proxy CSCF shall generate and insert an appropriate R-P header based upon the information received in the session set-up request. The requirements to be supported by the functional entities in
47、IPCablecom2 networks are included in clause 7. The R-P header syntax, as defined by IETF RFC 4412, requires defining a namespace, values for priority levels, an algorithm to be used by the RP actors and new response (error) codes relevant for this namespace. The namespace definition must be register
48、ed with IANA. IETF RFC 4412 defines two algorithms for providing priority even though the new namespace definition may specify other algorithms. The two algorithms defined by the RFC are preemption and priority queuing. Appendix I illustrates the components required for a namespace definition accord
49、ing to IETF RFC 4412. Annexes A to E identify the namespace specific to each ITU region. 6.2 Priority-enabling mechanisms in IPCablecom2 Appendix II of b-ITU-T J.360 and ITU-T J.179 define interfaces to set up policies and control for enabling QoS to support resource management for new services, including those that require preferential treatment. Even though QoS is not meant to imply priority, one of the considerations for the QoS architecture in IPCablecom2 networks is prioritization for sessions. IT
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