1、 International Telecommunication Union ITU-T Series QTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 55(04/2007) SERIES Q: SWITCHING AND SIGNALLING Signalling requirements at the interface between AS-FE and S-CSC-FE ITU-T Q-series Recommendations Supplement 55 ITU-T Q-SERIES RECOMMENDATIO
2、NS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEMS
3、No. 4, 5, 6, R1 AND R2 Q.120Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SA
4、TELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR THE N
5、GN Q.3000Q.3999 For further details, please refer to the list of ITU-T Recommendations. Q series Supplement 55 (04/2007) i Supplement 55 to ITU-T Q-series Recommendations Signalling requirements at the interface between AS-FE and S-CSC-FE Summary Supplement 55 to ITU-T Q-series Recommendations descr
6、ibes the general signalling requirements at the interface between AS-FE and S-CSC-FE for session-based services of NGN release 1. Source Supplement 55 to ITU-T Q-series Recommendations was agreed on 27 April 2007 by ITU-T Study Group 11 (2005-2008). Keywords NGN, Session control, Signalling requirem
7、ents, SIP Application. ii Q series Supplement 55 (04/2007) 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 a permanent organ of ITU. ITU-T is responsible
8、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 for study by the ITU-T st
9、udy 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 prepared on a collaborative basi
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15、 reproduced, by any means whatsoever, without the prior written permission of ITU. Q series Supplement 55 (04/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 4 Abbreviations and acronyms 2 5 Reference architecture 3 6 General requirements 4 7 Applications 4 8 S-CSC-FE functional re
16、quirements 5 8.1 Functional model 5 8.2 Registration trigger. 6 8.3 Originating call trigger . 7 8.4 Terminating call trigger 7 8.5 Session release trigger 7 9 AS-FE functional requirements 7 9.1 Functional model 7 9.2 Interworking modes 8 9.3 Application call processing 10 10 S-CSC-FE signalling re
17、quirements 11 10.1 3rd party registration 11 10.2 Service request 11 11 AS-FE signalling requirements. 11 11.1 Terminating UA 11 11.2 Originating UA. 12 11.3 Redirect server 12 11.4 Proxy. 12 11.5 3rd party call control 12 Q series Supplement 55 (04/2007) 1 Supplement 55 to ITU-T Q-series Recommenda
18、tions Signalling requirements at the interface between AS-FE and S-CSC-FE 1 Scope This Supplement provides signalling interface requirements for session services in NGN release 1 scope. The interface to be specified commonly lies between ASF/SSF (application support function/service support function
19、) and service components in SCF (service control function). In NGN Release 1 stage, the ASF/SSF includes AS-FE, APL-GW-FE, SS-FE and APL-SCM-FE, and the SCF includes S-CSCF for IP multimedia service component and call server for PIEA (PSTN/ISDN emulation architecture) component. The AS-FE is referre
20、d to as a representative FE among the other FEs in ASF/SSF. 2 References ITU-T H.248.1 ITU-T Recommendation H.248.1 (2002), Gateway control protocol: version 2. ITU-T Q.1224 ITU-T Recommendation Q.1224 (1997), Distributed functional plane for intelligent network Capability Set 2. ITU-T Sup.1-Y ITU-T
21、 Y.2000 series Supplement 1 (2006), NGN release 1 scope. ITU-T Y.2012 ITU-T Recommendation Y.2012 (2006), Functional requirements and architecture of the NGN release 1. ITU-T Y.2021 ITU-T Recommendation Y.2021 (2006), IMS for Next Generation Networks. ITU-T Y.2031 ITU-T Recommendation Y.2031 (2006),
22、 PSTN/ISDN emulation architecture. ITU-T Y.2201 ITU-T Recommendation Y.2201 (2007), NGN release 1 requirements. ITU-T Y.2211 ITU-T Recommendation Y.2211 (2007), IMS-based real-time conversational multimedia services over NGN. ETSI TS 123.218 ETSI TS 123 218 (2007), IP Multimedia (IM) Session Handlin
23、g; IM Call Model. ETSI TS 123.228 ETSI TS 123 228 (2007), IP Multimedia Subsystem (IMS). IETF RFC 3261 IETF RFC 3261 (2002), SIP: Session Initiation Protocol. 3 Definitions This Supplement uses the following terms: 3.1 application support functional entity ITU-T Y.2012: It supports generic applicati
24、on server functions including hosting and executing services. The examples of AS-FE are call feature application servers, presence servers, various messaging servers, conferences servers, home application support servers and so on. NOTE In this Supplement, the AS-FE represents the functional entitie
25、s of ASF/SSF because they have functionally the same interface with S-CSC-FE. 3.2 serving call session control functional entity ITU-T Y.2012: It handles functionality related to session control of session setup, modification, and teardown, and routing of session messages. It performs the functions
26、of registration, service triggering, determination of routing of 2 Q series Supplement 55 (04/2007) session control messages. The S-CSC-FE maintains a session-related state as needed by the network operator for support of services. NOTE In this Supplement, the S-CSC-FE represents the functional enti
27、ties of SCF including IMS-based and call-server-based service components, because they have functionally the same interface with AS-FE. 3.3 service trigger ITU-T Q.1290: A stimulus for initiating an action in support of a service on reception of a message or information. 4 Abbreviations and acronyms
28、 This Supplement uses the following abbreviations and acronyms: APL Application APL-GW-FE Application Gateway Functional Entity APL-SCM-FE Application Service Coordination Manager Functional Entity ASF Application Support Function AS-FE Application Support Functional Entity AS-ILCM Application Serve
29、r Incoming Leg Control Model AS-OLCM Application Server Outgoing Leg Control Model B2BUA Back-to-Back User Agent BCSM Basic Call State Model CCF Call Control Function I-CSC-FE Interrogating Call Session Control Functional Entity iFC Initial Filter Criteria ILCM Incoming Leg Control Model ILSM Incomi
30、ng Leg State Model IMS IP Multimedia Subsystem OLCM Outgoing Leg Control Model OLSM Outgoing Leg State Model P-CSC-FE Proxy Call Session Control Functional Entity POTS Plain Old Telephone Service RF Routing Function SCF Service Control Function S-CSC-FE Serving Call Session Control Functional Entity
31、 SIF Signalling Interworking Function SIP Session Initiation Protocol SIP UA SIP User Agent SSF Service Support Function SS-FE Service Switching Functional Entity UAC User Agent Client VAS Value-Added Services Q series Supplement 55 (04/2007) 3 5 Reference architecture Figure 5-1 depicts a reference
32、 architecture for controlling session application services based on the NGN architecture ITU-T Y.2012. It highlights the reference point between ASF/SSF and two SCFs which are the IMS service component and the call-server-based PIEA service component. The interface A-S4 is defined in NGN functional
33、architecture ITU-T Y.2012 and used to deliver information related to service control, including service triggering and call-control-related information. The A-S4 interface corresponds to the ISC for the IP multimedia service component ITU-T Y.2021, and I-9 for the PSTN/ISDN emulation service compone
34、nt ITU-T Y.2031. The A-S4, ISC and I-9 are the equivalent interfaces between APL-GW-FE, APL-SCM-FE, SS-FE and AS-FE in ASF/SSF and S-CSCF or SIF, RF and CCF in SCF. The SIF/CCF/RF of PIEA and S-CSCF of IMS correspond to S-CSC-FE ITU-T Y.2012 and provide the same interface function to the ASF/SSF. Si
35、nce the IMS-based PIEA and IMS components have the same architecture from the viewpoint of interface with AS-FE, the service components are divided into IMS-based and call-server-based PIEA service components in Figure 5-1. Call Server basedPSTN/ISDN EmulationService ComponentIP MultimediaService Co
36、mponent A-S4 (ISC, I9)Application/Service Support FunctionsCCFSIFS-CSCFSS-FE*APL-GW-FE APL-SCM-FE AS-FERF S-CSC-FE * For CS-PES case, SS-FE is located in PIEA ITU-T Y.2031 component Figure 5-1 Reference architecture for session service control 4 Q series Supplement 55 (04/2007) 6 General requirement
37、s This clause describes the general requirements for the interface between AS-FE and S-CSC-FE. Justification references for each item are noted within brackets. 1) The interface is required to support multimedia session services including voice, video, text, etc. ITU-T Sup.1-Y. 2) The interface is r
38、equired to support QoS control during session set-up ITU-T Sup.1-Y. 3) The interface is required for the AS-FE to be independent from the details of the network, such as network protocols ITU-T Y.2201. 4) The interface is required to use SIP protocol for service control ITU-T Sup.1-Y. 5) The interfa
39、ce is required to process multiple sessions simultaneously and each session should be uniquely identified ITU-T Y.2201. 6) The interface is required to identify each session endpoint using the session identification mechanism ITU-T Y.2201. 7) The interface is required for the AS-FE to register the p
40、ossible service lists to provide, and un-register the lists when it does not provide the services any more ITU-T Y.2012. 8) The interface is required to support a flexible service trigger mechanism and to exchange call and service control related information ITU-T Y.2012. 9) The interface is require
41、d for AS-FE to provide disconnection reason information to S-CSC-FE in case of call disconnection. 10) The interface is required for AS-FE to connect and control MRC-FE through the S-CSC-FE ITU-T Y.2012. 11) The interface is required for AS-FE to receive the session event notification such as succes
42、sful connection, called party busy, network busy, connection fail, off-hook, on-hook, flash hook, or mid-call event from the S-CSC-FE. 12) The interface is required for S-CSC-FE and AS-FE to deal with service interaction problems when multiple services are invoked in AS-FEs simultaneously. 7 Applica
43、tions This Supplement specifies the signalling requirements for NGN session-based application services. NGN release 1 scope ITU-T Sup.1-Y includes the following session services: real-time conversational voice services; messaging services, such as IM, SMS, MMS, etc.; push-to-talk over NGN (PoN); pre
44、sence and general notification services; PSTN/ISDN emulation services; PSTN/ISDN simulation services. ITU-T Y.2211 specifies IMS-based real-time conversational multimedia service requirements, service features, service architectures and implementation scenarios. It includes a comprehensive set of se
45、ssion-related service features, PSTN/ISDN simulation services, and IP multimedia application services. The AS-FEs hosting the above services and S-CSC-FE to provide session services should satisfy the signalling requirements specified in this Supplement. Q series Supplement 55 (04/2007) 5 8 S-CSC-FE
46、 functional requirements This clause reuses the functional requirements of IMS ETSI TS 123.228 unless it is described otherwise. IMS and call-server-based functional models are presented in separate clauses. 8.1 Functional model 8.1.1 IMS-based functional model See Figure 8-1. Q.Supp.55(07)_F8-1HSSA
47、S-ILCM AS-OLCMILCM OLCMILSM OLSMApplication serverIncoming leg Outgoing legRegistrar, NotifierS-CSCFFigure 8-1 IMS-based functional model of AS and S-CSCF The S-CSCF includes the combined I/OLSM, the ILCM and OLCM and the registrar and notifier. There is a single combined I/OLSM, which shall be able
48、 to store session state information. It may act on each leg independently, acting as a SIP proxy, redirect server or user agent depending on the information received in the SIP request, the filter conditions specified, or the state of the session. It shall be possible to split the application handli
49、ng on each leg and treat each endpoint differently. There is a single ILCM, which shall store transaction state information. There is a single OLCM, which shall store transaction state information. The registrar and notifier component handles registration and subscription to, and notification of, registration events ETSI TS 123.228. 6 Q series Supplement 55 (04/2007) 8.1.2 Call-server-based functional model See Figure 8-2. Q.Supp.55(07)_F8-2
