1、 International Telecommunication Union ITU-T Y.2271TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2006) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Service aspects: Interoperability of services and networks in NGN
2、Call server-based PSTN/ISDN emulation ITU-T Recommendation Y.2271 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications and middleware Y.200Y.299 Network asp
3、ects Y.300Y.399 Interfaces and protocols Y.400Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET PROTOCOL ASPECTS General Y.1000Y.1099 Services and applications Y.1100Y.1199 Architecture, access,
4、 network capabilities and resource management Y.1200Y.1299 Transport Y.1300Y.1399 Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, administration and maintenance Y.1700Y.1799 Charging Y.1800Y.1899 NEXT GENERATION NETWORKS Frameworks
5、 and functional architecture models Y.2000Y.2099 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of services and networks in NGN Y.2250Y.2299 Numbering, naming and addressing Y.2300Y.2399 Ne
6、twork management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. Y.2271 (09/2006) i ITU-T Recommendation Y.2271 Call server-based PSTN/ISDN
7、 emulation Summary The NGN shall support PSTN/ISDN emulation. One mechanism for providing this functionality is the use of a Call Server-based architecture. This Recommendation identifies service and network capabilities for this call server-based solution. Source ITU-T Recommendation Y.2271 was app
8、roved on 13 September 2006 by ITU-T Study Group 13 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Call server, emulation, ISDN, PES, PSTN ii ITU-T Rec. Y.2271 (09/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field
9、of telecommunications. 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 to standardizing telecommunications on a worldwide basis. The World
10、 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 Recommendations is covered by the procedure laid down in WTSA Resolution 1. In s
11、ome 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 conciseness to indicate both a telecommunication administration and a recogni
12、zed 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 is achieved when all of these mandatory provisions are met. The words
13、 “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. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that t
14、he 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, whether asserted by ITU members or others outside of the Recommendation
15、 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 cautioned that this may not represent the latest information and are
16、therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-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. Y.2271 (09/2006) iii CONTENTS Page 1 Scope 1 2 Re
17、ferences. 1 3 Definitions 2 4 Abbreviations 2 5 Conventions 4 6 PSTN/ISDN emulation in NGN . 4 7 Service and network capabilities 5 7.1 Service capabilities. 5 7.2 Network capabilities. 5 8 Relevant network elements. 8 8.1 Application server 8 8.2 Application server gateway 8 8.3 User profile server
18、 8 8.4 Call server. 8 8.5 Gateways 11 8.6 Media server (MS) 11 Appendix I Mapping functional entities to network elements 12 Appendix II Basic call control scenario in call server-based PES 13 II.1 Intra CS-PES call 13 II.2 Scenario 5: Call between CS-PES user and PSTN, ISDN or PLMN. 15 II.3 Scenari
19、o 6: Inter CS-PES call. 15 II.4 Scenario 7: Call between CS-PES user and user of other IP networks 16 II.5 Scenario 8: Call between two PSTN/ISDN/PLMN users via CS-PES 16 Appendix III Reference points and protocols . 17 BIBLIOGRAPHY 18 ITU-T Rec. Y.2271 (09/2006) 1 ITU-T Recommendation Y.2271 Call s
20、erver-based PSTN/ISDN emulation 1 Scope This Recommendation describes the service and network capability requirements for a call server-based (CS-based) PSTN/ISDN emulation component. It also provides a list of network elements used in conjunction with the CS-based PSTN/ISDN emulation component. App
21、endix II also provides a number of call control scenarios for CS-based PSTN/ISDN emulation component. Administrations may require operators and service providers to take into account national regulatory and national policy requirements in implementing this Recommendation. 2 References The following
22、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 revision; users of this Recommenda
23、tion 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. The reference to a document within this Recommendation does not give
24、it, as a stand-alone document, the status of a Recommendation. E.360.1 ITU-T Recommendation E.360.1 (2002), Framework for QoS routing and related traffic engineering methods for IP-, ATM-, and TDM-based multiservice networks. E.360.2 ITU-T Recommendation E.360.2 (2002), QoS routing and related traff
25、ic engineering methods Call routing and connection routing methods. E.600 ITU-T Recommendation E.600 (1993), Terms and definitions of traffic engineering. G.711 ITU-T Recommendation G.711 (1988), Pulse code modulation (PCM) of voice frequencies. G.723.1 ITU-T Recommendation G.723.1 (2006), Dual rate
26、 speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s. G.729 ITU-T Recommendation G.729 (2007), Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear prediction (CS-ACELP). H.248.1 ITU-T Recommendation H.248.1 v3 (2005), Gateway control protoco
27、l: Version 3 (and its specific capabilities defined in H.248.x-series of Recommendations). Q.826 ITU-T Recommendation Q.826 (2000), Routing management model. X.110 ITU-T Recommendation X.110 (2002), International routing principles and routing plan for Public Data Networks. X.805 ITU-T Recommendatio
28、n X.805 (2003), Security architecture for systems providing end-to-end communications. Y.2031 ITU-T Recommendation Y.2031 (2006), PSTN/ISDN emulation architecture. Y.2261 ITU-T Recommendation Y.2261 (2006), PSTN/ISDN evolution to NGN. RFC 3261 IETF RFC 3261 (2002), SIP: Session Initiation Protocol.
29、EN 301 703 ETSI European Standard, EN 301 703 V7.0.2 (1999), Digital cellular telecommunications system (Phase 2+) (GSM); Adaptive Multi-Rate (AMR); Speech processing functions; General description. 2 ITU-T Rec. Y.2271 (09/2006) 3 Definitions This Recommendation defines the following terms: NOTE In
30、this clause the aaa notation after the title of a term indicates source of the definition for that term. 3.1 access border gateway (ABG): A packet gateway between an access network and a core network. 3.2 access gateway (AG) Y.2261: A unit that allows end users with various accesses (e.g., PSTN, ISD
31、N, V5.x) connection to the packet node of NGN. NOTE The AG may be embedded in an access node, which serves also other access interfaces (e.g., xDSL, LAN). Such access nodes are also known as multi-service access nodes (MSAN). 3.3 application server (AS): A unit that interacts with the call server an
32、d the user profile server to support service execution. 3.4 application server gateway (ASG): A unit that interworks between application server and call server. NOTE In IMS, ASG interworks between the application server and the core IMS. 3.5 call server (CS): The core element of a CS-based PSTN/ISDN
33、 emulation component, which is responsible for call control, media resource control, call routing, user profile and subscriber authentication, authorization and accounting. Depending on its role, the behaviour of the call server may be different. In these cases, the role of the call server is identi
34、fied, for example, as “Access call server“, “Breakout call server“, “IMS call server“, “Routing call server“ or “Gateway call server“. 3.6 media server (MS): A network element providing the media resource processing function for telecommunication services in NGN. 3.7 PSTN/ISDN emulation: Provides PS
35、TN/ISDN service capabilities and interfaces using adaptation to an IP infrastructure. NOTE Not all service capabilities and interfaces have to be present to provide an emulation. 3.8 interconnection border gateway (IBG): A unit responsible for packet interworking between two service providers core n
36、etworks. 3.9 residential gateway (RG): A unit that interworks PSTN/ISDN user equipments to a packet network. A residential gateway is located at the customer premises. 3.10 signalling gateway (SG) Y.2261: A unit that provides out-of-band call control signalling conversion between the NGN and other n
37、etworks (e.g., between a Call server in NGN and a STP or SSP in SS7). 3.11 trunking media gateway (TMG) Y.2261: A unit that provides interfaces between the packet nodes of the NGN and the circuit-switched nodes (e.g., transit exchange, local exchange, international exchange) of PSTN/ISDN for bearer
38、traffic. The TMG provides any needed conversion to the bearer traffic. 4 Abbreviations This Recommendation uses the following abbreviations: ABG Access Border Gateway ACS Access Call Server AG Access Gateway AGCF Access Gateway Control Function ITU-T Rec. Y.2271 (09/2006) 3 AMG Access Media Gateway
39、AS Application Server ASG Application Server Gateway ASR Automatic Speech Recognition BCS Breakout Call Server BICC Bearer Independent Call Control BRI Basic Rate Interface CAMEL Customized Applications for Mobile Network Enhanced Logic CCF Call Control Function CDR Call Detail Record CS Call Server
40、 CS-based Call Server based CSCS Call Session Control Server CS-PES Call Server-based PSTN/ISDN Emulation Service component DTMF Dual Tone Multi Frequency FE Function Entity GCS Gateway Call Server IBG Interconnection Border Gateway ICS IMS Call Server IMS IP Multimedia Subsystem IN Intelligent Netw
41、ork INAP Intelligent Network Application Part IPSec IP Security ISDN Integrated Services Digital Network ISUP ISDN User Part IVR Interactive Voice Response MGCF Media Gateway Control Function MRCF Media Resource Control Function MRP Media Resource Process MS Media Server NACF Network Attachment Cont
42、rol Function NGN Next Generation Network PES PSTN/ISDN Emulation Service component PIEA PSTN/ISDN Emulation Architecture PLMN Public Land Mobile Network POTS Plain Old Telephone Service PRI Primary Rate Interface 4 ITU-T Rec. Y.2271 (09/2006) PSAP Public Safety Answering Point PSTN Public Switched T
43、elephone Network QoS Quality of Service RACF Resource and Admission Control Function RCS Routing Call Server RF Routing Function RG Residential Gateway SCP Service Control Point SG Signalling Gateway SIGTRAN Signalling Transport SIP Session Initiation Protocol SIP-I SIP with encapsulated ISUP SPF Se
44、rvice Provider Function SSF Service Switching Function TDR Telecommunications for Disaster Relief TMG Trunking Media Gateway UMTS Universal Mobile Telecommunications System UPS User Profile Server WIN Wireless Intelligent Network 5 Conventions None. 6 PSTN/ISDN emulation in NGN PSTN/ISDN emulation,
45、as one of the service components of NGN, provides PSTN/ISDN basic and supplementary services, and co-exists with the IP Multimedia component, the streaming component, and other components. It interworks with the existing networks and other components of NGN. PSTN/ISDN emulation satisfies the followi
46、ng basic requirements: In terms of service provisioning, it inherits PSTN/ISDN basic and supplementary services, and provides IN services. In terms of user-network connection, it supports existing PSTN/ISDN UNI interfaces. Therefore, PSTN/ISDN end users may use existing services and existing termina
47、ls under the PSTN/ISDN emulation environment, without the knowledge of network being replaced by NGN. The term “call server-based“ indicates that service control logic and service execution environment is primarily located in a call/session control server (CSCS; briefly call server (CS). The CS is t
48、herefore the responsible network entity for service delivery (often also called as “anchor point of services“). This function relates to the service switching function (SSF) in PSTN/ISDN. Completely opposite to the CS-based service control concept is the IMS-based approach, because the application s
49、erver (AS) houses the service control logic and service execution environment behind CSCS entities. ITU-T Rec. Y.2271 (09/2006) 5 7 Service and network capabilities 7.1 Service capabilities The CS-based PSTN/ISDN emulation component should support: PSTN/ISDN teleservices and supplementary services as per I.240 and I.250 series of ITU-T Recommendations. Capabilities provided by the application server (AS). Capabilities provided by traditional IN. Public interest services. 7.2 Network capabilities 7
