ECMA TR 91-2005 Enterprise Communication in Next Generation Corporate Networks (NGCN) involving Public Next Generation Networks (NGN) (1st Edition)《涉及公共下一代网络(NGN)的下一代企业网络(NGCN)中的企业.pdf

1、 ECMA TR/91 1stEdition / December 2005 Enterprise Communication in Next Generation Corporate Networks (NGCN) involving Public Next Generation Networks (NGN) Technical Report ECMA TR/91 1stEdition / December 2005 Enterprise Communication in Next Generation Corporate Networks (NGCN) involving Public N

2、ext Generation Networks (NGN) Ecma International Rue du Rhne 114 CH-1204 Geneva T/F: +41 22 849 6000/01 www.ecma-international.org IW TR-091.doc 13/12/2005 15:16 . Introduction This Ecma Technical Report provides an overview of IP-based enterprise communication from/to Corporate telecommunication Ne

3、tworks (CNs) (also known as enterprise networks) including aspects of privately used home networks accessing public next generation networks (NGN). This Technical Report is based upon the practical experience of Ecma member companies and the results of their active and continuous participation in th

4、e work of ISO/IEC JTC1, ITU-T, ETSI, IETF and other international and national standardization bodies. It represents a pragmatic and widely based consensus. This Ecma Technical Report has been adopted by the General Assembly of December 2005. Table of contents1 Scope 1 2 References 1 3 Definitions 1

5、 3.1 Corporate telecommunication Network (CN) 2 3.2 Next Generation CN (NGCN) 3.3 Next Generation Network (NGN) 3.4 Virtual Private Network (VPN) 1 2 3.5 Application Service Provider (ASP) 3.6 Session Service Provider (SSP) 3.7 Transport Service Provider (TSP) 4 Abbreviations 2 5 Background 3 5.1 Pr

6、ovision of services by NGNs 5.1.1 Levels of service provision 5.1.2 Use of NGN services by NGCNs 5 5.1.3 Home NGN 5 5.2 Management considerations 6 Basic Configurations and General Requirements 6 6.1 Scenario 1 - Communication between NGCNs via an NGN using a VPN 6 6.2 Scenario 2 - Communication bet

7、ween NGCNs via an NGN not using a VPN 7 6.3 Scenario 3 - Communication between NGCN and TE via an NGN using a VPN 8 6.4 Scenario 4 - Communication between NGCN and TE via an NGN not using a VPN 9 6.5 Scenario 5 - Communication between NGCN and PSTN/ISDN via an NGN 9 6.6 General requirements on NGNs

8、10 6.7 General requirements on NGNs concerning measures for compliance with regulations 11 7 Technical issues and requirements on NGN related to session service provision 12 7.1 Signalling architecture 12 7.1.1 Scenario 1 - Communication between NGCNs using a VPN 14 7.1.2 Scenario 2 - Communication

9、between NGCNs not using a VPN 14 7.1.3 Scenario 3 - Communication between NGCN and TE using a VPN 14 - i - 7.1.4 Scenario 4 - Communication between NGCN and TE not using a VPN 15 7.1.5 Scenario 5 - Communication between NGCN and PSTN/ISDN 15 7.2 NAT traversal 16 7.2.1 NAT traversal for SIP signallin

10、g 16 7.2.2 NAT traversal for media streams 17 7.3 Firewall traversal 18 7.3.1 Scenario 1 - Communication between NGCNs using a VPN 19 7.3.2 Scenario 2 - Communication between NGCNs not using a VPN 19 7.3.3 Scenario 3 - Communication between NGCN and TE using a VPN 19 7.3.4 Scenario 4 - Communication

11、 between NGCN and TE not using a VPN 19 7.3.5 Scenario 5 - Communication between NGCN and PSTN/ISDN 19 7.4 Identification 19 7.5 Provision of identification information 20 7.5.1 Scenario 1 - Communication between NGCNs using a VPN 21 7.5.2 Scenario 2 - Communication between NGCNs not using a VPN 21

12、7.5.3 Scenario 3 - Communication between NGCN and TE using a VPN 21 7.5.4 Scenario 4 - Communication between NGCN and TE not using a VPN 21 7.5.5 Scenario 5 - Communication between NGCN and PSTN/ISDN 21 7.6 Security 22 7.6.1 Signalling security 22 7.6.2 Media security 24 7.7 Session policy 27 7.7.1

13、Scenario 1 - Communication between NGCNs using a VPN 27 7.7.2 Scenario 2 - Communication between NGCNs not using a VPN 27 7.7.3 Scenario 3 - Communication between NGCN and TE using a VPN 27 7.7.4 Scenario 4 - Communication between NGCN and TE not using a VPN 27 7.7.5 Scenario 5 - Communication betwe

14、en NGCN and PSTN/ISDN 27 7.8 Emergency calls 27 7.8.1 Scenario 1 - Communication between NGCNs using a VPN 28 7.8.2 Scenario 2 - Communication between NGCNs not using a VPN 28 7.8.3 Scenario 3 - Communication between NGCN and TE using a VPN 28 7.8.4 Scenario 4 - Communication between NGCN and TE not

15、 using a VPN 28 7.8.5 Scenario 5 - Communication between NGCN and PSTN/ISDN 28 7.9 Geographic location 29 7.9.1 Scenario 1 - Communication between NGCNs using a VPN 29 7.9.2 Scenario 2 - Communication between NGCNs not using a VPN 29 7.9.3 Scenario 3 - Communication between NGCN and TE using a VPN 2

16、9 7.9.4 Scenario 4 - Communication between NGCN and TE not using a VPN 29 7.9.5 Scenario 5 - Communication between NGCN and PSTN/ISDN 29 - ii - 1 Scope This Technical Report identifies key use cases for communication with or between IP-based Next Generation Corporate Networks (NGCN) involving public

17、 next generation networks (NGN), analyses these use cases in terms of available or planned standardised technology and identifies requirements that will have to be met. This Technical Report investigates configurations involving NGCNs and NGNs and their interoperating requirements. Non-IP-based inte

18、roperation, i.e. using circuit-switched technology, between NGCNs and NGNs is outside the scope of this Technical Report. This Technical Report does not discriminate between wireless and wired access technology. All mobility aspects are outside the scope of this Technical Report. They are covered by

19、 a companion Technical Report ECMA TR/92 1. Application considerations such as IP Centrex and CSTA (Computer Supported Telecommunications Applications) are outside the scope of this Technical Report. 2 References 1 ECMA TR/92 Corporate Telecommunication Networks Mobility for Enterprise Communication

20、 2 ECMA-307 Corporate Telecommunication Networks - Signalling Interworking between QSIG and H.323 - Generic Functional Protocol for the Support of Supplementary Services (June 2000) 3 ITU-T Rec. H.323 Packet-based multimedia communications systems 4 IETF RFC 3261 SIP: Session Initiation Protocol 5 I

21、ETF RFC 3489 Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs) (STUN) 6 IETF RFC 3711 The Secure Real-time Transport Protocol (SRTP) 7 IETF RFC 3761 The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)

22、 8 IETF RFC 3966 The tel URI for Telephone Numbers 9 IETF RFC 2401 Security Architecture for the Internet Protocol (IPSEC) 3 Definitions For the purposes of this Technical Report the following definitions apply: 3.1 Corporate telecommunication Network (CN) 2 Sets of equipment (Customer Premises Equi

23、pment and/or Customer Premises Networks) that are located at geographically dispersed locations and are interconnected to provide telecommunication services to a defined group of users. 3.2 Next Generation CN (NGCN) A self-contained corporate network designed to take advantage of emerging IP-based c

24、ommunications solutions and that can have its own applications and service provisioning. 3.3 Next Generation Network (NGN) A packet based public network able to provide telecommunication services, able to make use of multiple QoS enabled transport technologies and in which service related functions

25、are independent of underlying transport related technologies. - 1 - 3.4 Virtual Private Network (VPN) 1 Virtual network that can deliver ubiquitous and secure connectivity over a shared network infrastructure (e.g. public carrier networks) using the same access policies as an enterprise network. 3.5

26、 Application Service Provider (ASP) An entity that provides telecommunication applications. 3.6 Session Service Provider (SSP) An entity that intervenes in and adds value to signalling for the establishment and control of multi-media sessions and optionally intervenes in and adds value to the multi-

27、media sessions themselves. 3.7 Transport Service Provider (TSP) An entity that provides IP connectivity. 4 Abbreviations ALG Application Layer Gateway API Application Protocol Interface ASP Application Service Provider B2BUA Back-to-Back User Agent CN Corporate telecommunication Network CSTA Compute

28、r Supported Telecommunications Applications IP Internet Protocol IPSEC IP Security ISDN Integrated Services Digital Network NAT Network Address Translator NGCN Next Generation Corporate Network NGN public Next Generation Network RTP Real-Time Protocol QoS Quality of Service SBC Session Border Contro

29、ller SDP Session Description Protocol SIP Session Initiation Protocol SRTP Secure Real-time Transport Protocol SSP Session Service Provider TCP Transmission Control Protocol TE Terminal Equipment TLS Transport Layer Security TSP Transport Service Provider UA User Agent UAC User Agent Client UAS User

30、 Agent Server - 2 - UDP User Datagram Protocol VoIP Voice over IP VPN Virtual Private Network 5 Background There has been a major evolution in enterprise telecommunications during the last few years. Prior to that, enterprise telecommunication networks (or corporate telecommunication networks, CN) w

31、ere based on 64 kbit/s circuit-switched technology, which had synergy with corresponding technology deployed in public Integrated Services Digital Networks (ISDN) and traditional analogue services. Those CNs primarily delivered a voice or telephony service to their users, although in principle they

32、were capable of other services too, including video and various types of data service. For communication outside the enterprise, CNs were able to interwork with public ISDNs. Many public networks also offered optional services to corporate customers, such as Centrex services and premise equipment le

33、asing and maintenance. With the advent of technologies for transmitting voice and other real-time media over the Internet Protocol (IP) (e.g., based on Real Time Protocol (RTP) and corresponding new signalling protocols (e.g., H.323, SIP), there was potential for providing telephony and other real-t

34、ime person-to-person services in the public Internet. Moreover, such services also became possible in the IP-based “intranets“ already deployed in enterprises for data services such as corporate email, file transfer, corporate web services and access to the world wide web. Enterprises saw advantages

35、 such as savings on infrastructure costs (e.g., one wire to the desk) and the introduction of innovative services that exploited the convergence of real-time and data communication. The traditional PBX (Private Branch Exchange) was replaced by or evolved to an “IP-PBX“ or soft switch that supported

36、IP connectivity to the desktop and IP connectivity between nodes. Direct IP-based transmission of multimedia between endpoints meant that switching capabilities were no longer required, except gateways for interworking with “legacy“ circuit-switched networks. IP-based CNs are continuing to evolve, t

37、o support additional services, improved security, improved QoS, etc A CN that fully embraces IP technology is referred to here as a Next Generation CN (NGCN). At present, NGCNs generally fall back to legacy circuit-switched techniques for communication outside the enterprise, e.g., using public ISDN

38、 or circuit-switching over leased lines. Gateways provide the necessary interworking of signalling and media. The next stage of evolution will be for NGCNs to extend IP-based communication outside the enterprise by using a public network that also supports IP-based communication. The public IP-based

39、 network may provide communication between the NGCN and another NGCN, between the NGCN and another IP-based user (e.g., residential user) or, via a gateway in the public network, between the NGCN and a legacy user or network. With this the NGCN no longer needs gateways to legacy networks (except whe

40、re required by existing investment or economic considerations) and can enjoy the benefits of end-to-end IP-based communication with appropriately equipped communication partners. The public Internet is one example of a public IP-based network that an NGCN can use for external communications. In addi

41、tion, some service providers are planning to offer public IP-based networks that offer improvements compared with the public Internet, e.g., in terms of QoS, security, mobility, applications, etc. These value added public IP-based networks are collectively known as Next Generation Networks (NGN). Th

42、is Technical Report aims to contribute to this next stage of evolution by looking at the issues involved in interoperating NGCNs and NGNs and to identify requirements on NGNs. 5.1 Provision of services by NGNs 5.1.1 Levels of service provision An NGN may provide services to NGCNs and NGCN users at a

43、 number of different levels. - 3 - The most basic level of service provision is IP connectivity. Differentiation from the Internet can be in the form of improved or guaranteed quality of service or security. For the purposes of this Technical Report an NGN that provides this level of service acts as

44、 a Transport Service Provider (TSP). A second level of service provision is in session establishment and control of communication sessions, e.g., voice, multimedia, messaging. Here the NGN adds value by being involved in the signalling protocol used to establish and control media sessions. For the p

45、urposes of this Technical Report the primary session control signalling protocol concerned is assumed to be the Session Initiation Protocol (SIP). Added value can include routing, provision of quality of service for media, provision of gateway services to legacy networks, assistance in NAT traversal

46、, etc For the purposes of this Technical Report an NGN that provides this level of service is known as a Session Service Provider (SSP). A third level of service provision is at the application level. Applications can be many and varied, but for the purposes of this Technical Report an application i

47、s assumed to be related to telecommunication in some way. An application may be able to monitor or control multi-media sessions (either directly or through a protocol or API such as CSTA) and may or may not be involved in media as well. Examples of applications that involve media include conferencin

48、g services, transcoding and translation services and call distribution centres. Examples of applications that monitor or control sessions but do not involve media include presence services, call logging services and UA configuration services. In addition, an application may be accessed through a ses

49、sion control protocol such as SIP. For the purposes of this Technical Report an NGN that provides this level of service is known as an Application Service Provider (ASP). An NGN may provide services at one or more of these levels. Not all services offered will be of interest to enterprise customers and of relevance for interworking with NGCNs. Enterprise customers may use different NGNs for different levels of service provision and may have different contractual relationships with each of these NGNs. In addition, for a given communication and depending on