软交换业务交换子系统的研究与实现
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摘要
下一代网络(NGN，Next Generation Network)，是传统的公用交换电话网(PSTN，Public Switched Telephone Network)和基于IP的分组网络融合的产物，它能够提供语音、视频、数据等多种综合业务。软交换是NGN的核心控制设备，为NGN提供具有实时性要求业务的呼叫控制和连接控制功能。在电路交换网中，呼叫控制、业务提供集中在一个交换系统中，而软交换的一个主要设计思想则是业务控制和呼叫控制相分离：软交换只负责提供最基本的呼叫控制功能，而智能控制则集中在应用层。基于这种分离性，软交换需要提供一个维系网络侧(提供呼叫控制能力)和应用侧(提供业务控制能力)联系的纽带，即业务交换功能。业务交换功能通过业务交换模型实现呼叫控制能力和业务控制能力的映射，是软交换支持业务的基础。
本文主要研究支持多媒体业务的软交换系统的业务交换模型，并基于这一模型设计与实现了软交换业务交换子系统。
软交换通过业务交换模型向上层应用提供两方面的能力：
1接受业务(应用侧)动态配置的业务触发标准和业务监视事件的能力以及在触发标准被满足或监视事件发生时向业务(应用侧)上报触发事件通知的能力；
2把业务(应用侧)的智能控制功能映射为网络侧的基本呼叫控制功能。
本文主要通过以下两方面研究和分析业务交换模型：一是以软交换系统会话控制模型为基础，分析以Parlay接口为代表的多方控制模型如何向基于单个呼叫方的会话控制模型转换，并由此研究和分析业务视图模型；二是以智能网业务触发模型为参考，提出了软交换系统的业务触发模型，并设计出能够提高系统吞吐量的多机分布式处理方案。
本文所提出的业务交换模型解决了如下两个问题：
1较为圆满地解决了开放业务接口(如Parlay)的多方控制模型向基于会话方控制方式的软交换呼叫控制模型的映射，增强了软交换对多方多媒体业务的支持能力。
2提出多机情况下业务检测点管理模块的重构方案，消除了在多机分布式处理条件下业务检测点管理模块的瓶颈，提高了系统的吞吐率。
软交换通过业务交换子系统，向业务平台充分提供其自身的网络能力，对多方多媒体业务的开发提供强大支持。
NGN, short for Next Generation Network, is derived from the combination of traditional PSTN and IP based packet network. NGN is able to provide various services, such as voice, video and data. Softswitch is the control function entity in NGN, which provides NGN with real-time service\call control and connection control.The call control function and the service control function assembled in one switching system of the public switched telephone network.One of the most important features of Softswitch is that the service control function departs from the call control function.Softswitch is only responsible for the basic call control,and the service control function was moved into the Application Server.Because of the departing,softswtich needs to establish the relationship between application layer and network layer,the service switch model of Softswitch takes charge of this mission.The service switch function,which is the base of service,is a must of softswitch.This paper focuses on the design and implementation of service switch model in Softswitch.
Softswitch provides two main functions for application layer through service switch model:
1. Providing a mechanism of service triggering and detection, Application Server can distribute its triggering criteria and interested events into Softswitch.when the interested event has happened or the triggering criteria has been triggered,softswitch can detect it and send a notification to Application Server;
2. Mapping the service control of application layer into the basic call control of network layer.
The paper mainly describes two aspect of the service switch model.One is service view model which is responsible for mapping the multi-party control mode into the basic call control mode;The other is service triggering and detection model which takes charge of detecting the triggering criteria and interested events.
The service switch model of Softswitch is solving these two problems:
1. Mapping the multi-party control mode of the standard service interface (such as Parlay APIs) into the single-party control mode of Softswitch, strongly enhancing the capability in supporting multimedia services for Softswitch;
2. Working out the detection point management solution for multi-agent environment, strongly improving the throughput of Softswitch.
Softswitch provides its network capability for Application Server through the service switch subsystem, gives strong support for developing multimedia services.
本文主要研究支持多媒体业务的软交换系统的业务交换模型，并基于这一模型设计与实现了软交换业务交换子系统。
软交换通过业务交换模型向上层应用提供两方面的能力：
1接受业务(应用侧)动态配置的业务触发标准和业务监视事件的能力以及在触发标准被满足或监视事件发生时向业务(应用侧)上报触发事件通知的能力；
2把业务(应用侧)的智能控制功能映射为网络侧的基本呼叫控制功能。
本文主要通过以下两方面研究和分析业务交换模型：一是以软交换系统会话控制模型为基础，分析以Parlay接口为代表的多方控制模型如何向基于单个呼叫方的会话控制模型转换，并由此研究和分析业务视图模型；二是以智能网业务触发模型为参考，提出了软交换系统的业务触发模型，并设计出能够提高系统吞吐量的多机分布式处理方案。
本文所提出的业务交换模型解决了如下两个问题：
1较为圆满地解决了开放业务接口(如Parlay)的多方控制模型向基于会话方控制方式的软交换呼叫控制模型的映射，增强了软交换对多方多媒体业务的支持能力。
2提出多机情况下业务检测点管理模块的重构方案，消除了在多机分布式处理条件下业务检测点管理模块的瓶颈，提高了系统的吞吐率。
软交换通过业务交换子系统，向业务平台充分提供其自身的网络能力，对多方多媒体业务的开发提供强大支持。
NGN, short for Next Generation Network, is derived from the combination of traditional PSTN and IP based packet network. NGN is able to provide various services, such as voice, video and data. Softswitch is the control function entity in NGN, which provides NGN with real-time service\call control and connection control.The call control function and the service control function assembled in one switching system of the public switched telephone network.One of the most important features of Softswitch is that the service control function departs from the call control function.Softswitch is only responsible for the basic call control,and the service control function was moved into the Application Server.Because of the departing,softswtich needs to establish the relationship between application layer and network layer,the service switch model of Softswitch takes charge of this mission.The service switch function,which is the base of service,is a must of softswitch.This paper focuses on the design and implementation of service switch model in Softswitch.
Softswitch provides two main functions for application layer through service switch model:
1. Providing a mechanism of service triggering and detection, Application Server can distribute its triggering criteria and interested events into Softswitch.when the interested event has happened or the triggering criteria has been triggered,softswitch can detect it and send a notification to Application Server;
2. Mapping the service control of application layer into the basic call control of network layer.
The paper mainly describes two aspect of the service switch model.One is service view model which is responsible for mapping the multi-party control mode into the basic call control mode;The other is service triggering and detection model which takes charge of detecting the triggering criteria and interested events.
The service switch model of Softswitch is solving these two problems:
1. Mapping the multi-party control mode of the standard service interface (such as Parlay APIs) into the single-party control mode of Softswitch, strongly enhancing the capability in supporting multimedia services for Softswitch;
2. Working out the detection point management solution for multi-agent environment, strongly improving the throughput of Softswitch.
Softswitch provides its network capability for Application Server through the service switch subsystem, gives strong support for developing multimedia services.
引文
[1]．龚双瑾，刘多，《下一代电信网的关键技术》，国防工业出版社，2003
[2]．麋正琨，王文鼐等著，《软交换技术与协议》，人民邮电出版社，2002．7
[3]．张雪丽，《软交换中的业务提供方式》，信息产业部通信标准研究所
[4]．赵慧玲，叶华，《以软交换为核心的下一代网络技术》，人民邮电出版社，2002
[5]. ITU-T Q.761(1999-12) Signalling System No. 7-ISDN User Part functional description
[6]. IETF RFC 3261 (2002-06) Session initiation protocol(SIP)
[7]. ITU-T Recommendation H.323 v2(1998) Packet-Based Multimedia Communications Systems
[8]. IETF RFC 3435 (2003-01) Media Gateway Control Protocol(MGCP)
[9]. ITU-T Recommendation H.248.1 Version 2 (2002-05) Gateway control protocol
[10]. ITU-T Recommendation Q. 1551 Version 2 (1997-06) Application of Intelligent Network Application Protocols (INAP)
[11]. ETSI GSM 09.02 version 4.19.1 (2000-12) Mobile Application Part (MAP) specification
[12]. 3GPP Technical Specification 25.413 v4.6.0 (2002-09) UTRAN Iu interface RANAP signalling(Release 4)
[13]．ITU-T IN CS-2建议Q．1224，国际电联，1997
[14]．叶力．Testsuite类库开发指南．正方兴技术文档．2003．9
[2]．麋正琨，王文鼐等著，《软交换技术与协议》，人民邮电出版社，2002．7
[3]．张雪丽，《软交换中的业务提供方式》，信息产业部通信标准研究所
[4]．赵慧玲，叶华，《以软交换为核心的下一代网络技术》，人民邮电出版社，2002
[5]. ITU-T Q.761(1999-12) Signalling System No. 7-ISDN User Part functional description
[6]. IETF RFC 3261 (2002-06) Session initiation protocol(SIP)
[7]. ITU-T Recommendation H.323 v2(1998) Packet-Based Multimedia Communications Systems
[8]. IETF RFC 3435 (2003-01) Media Gateway Control Protocol(MGCP)
[9]. ITU-T Recommendation H.248.1 Version 2 (2002-05) Gateway control protocol
[10]. ITU-T Recommendation Q. 1551 Version 2 (1997-06) Application of Intelligent Network Application Protocols (INAP)
[11]. ETSI GSM 09.02 version 4.19.1 (2000-12) Mobile Application Part (MAP) specification
[12]. 3GPP Technical Specification 25.413 v4.6.0 (2002-09) UTRAN Iu interface RANAP signalling(Release 4)
[13]．ITU-T IN CS-2建议Q．1224，国际电联，1997
[14]．叶力．Testsuite类库开发指南．正方兴技术文档．2003．9