【作者】 荀兆勇；

【导师】 廖建新；

【作者基本信息】 北京邮电大学 ， 计算机应用技术， 2008， 博士

【摘要】 随着移动通信网络的演进,对通信网络所提供服务的要求越来越高。IP(InternetProtocol)多媒体子系统(IP Multimedia Subsystem,IMS)使得第三代(3G)移动网络成为可以提供全业务的融合网络,IMS成为研究的热点。IMS中可提供业务的多样性和业务的服务质量是IMS网络成功与否的关键,而要保证业务的服务质量,必须保证IMS网络业务的快速有效触发。业务触发主要包括应用/业务触发框架(Application TriggeringArchitecture,ATA)、业务触发数据(Service Triggering Data,STD)、业务触发算法(ServiceTriggering Algorithm,STA)和业务触发协议(Service Triggering Protocol,STP)等内容。本文对IMS的业务触发进行研究,主要涉及如下几个方面:1、应用触发框架方面,主要是对现有应用触发框架进行了增强,并提出了一种新的应用触发框架以解决现有框架中存在的问题;2、业务触发数据方面,主要是对现有3GPP(3rd Generation Partnership Project)规范中的业务触发数据进行研究,分析其存在的问题并提出了一种基于业务键的触发数据;3、业务触发算法方面,主要是性能方面的研究,分析了现有3GPP业务触发算法的性能问题,并提出了几种优化的业务触发算法以提高IMS触发系统的性能。4、业务逻辑触发(Service Logic Triggering,SLT)方面,分析了现有3GPP规范中尚未标准化的部分,提出了一种SIP应用服务器业务逻辑触发机制,并研究了该机制下整个IMS业务触发的性能。本文对研究过程中取得的主要创新成果进行了详细阐述。这些创新工作简要归纳如下:1)IMS应用触发框架方面:在现有3GPP应用触发框架中,3GPP只定义并实现了初始过滤准则(initial Filter Criteria,iFC),虽然也定义了后续过滤准则(subsequentFilter Criteria,sFC),但并未给出sFC的具体实现方式。为了解决这个问题,增强现有3GPP应用触发框架,提出了一种基于SIP(Session Initiation Protocol)头的sFC的实现方式,该实现方式可以有效控制后续SIP消息的触发,增加了后续SIP消息路由的灵活性;针对提出的sFC实现方式,通过分析发现基于iFC+sFC的业务触发缺乏足够的灵活性,且存在不必要的业务触发而造成S-CSCF(ServingCall Session Control Function)和应用服务器(Application Server,AS)不得不处理额外的SIP消息,所以不可避免地引入了额外的网络处理时延的问题。为了解决这些问题,提出了一种基于呼叫状态的应用触发框架(Call-state based ATA,CATA)。在举例说明了CATA下的业务触发后,分析、讨论了iFC、sFC和cFC(call-state based Filter Criteria)之间的关系。2)IMS业务触发数据方面:分析了现有3GPP业务触发数据中存在的问题,提出了一种基于SIP头的业务键(Service Key)的实现方式,具有如下优点:a)S-CSCF和应用服务器可以更加简洁地完成业务/业务逻辑的触发,提高了业务触发性能;b)解决了初始过滤准则的冲突问题,使多个应用服务器之间的iFC互不干扰,防止了由于新业务的部署而引发新旧业务之间的iFC冲突;c)使S-CSCF一次触发多个业务成为可能。3)IMS业务触发算法方面:研究了现有3GPP提出的基于iFC的业务触发算法的性能,提出了三种业务触发算法以提高现有业务触发的性能:a)在本文提出的sFC实现方式的基础上,提出了一种新的基于iFC+sFC的动态业务触发算法(NewDynamic STA based on iFC and sFC,NDSTA),通过性能分析发现,NDSTA可以有效降低S-CSCF和应用服务器的信令流量负载,进而增加了整个系统的吞吐量,减少了会话建立时延。b)提出了一种基于组的业务触发算法(Group basedSTA,GSTA),S-CSCF通过一次触发一组应用服务器/业务的方式,减少了业务触发的次数,进而减少了S-CSCF的信令流量负载,提高了S-CSCF的吞吐量和性能。c)在CATA下,提出了一种基于呼叫状态的业务触发算法(Call-state basedSTA,CSTA),通过性能分析发现CSTA是一种灵活有效的业务触发算法。同时基于应用服务器/业务分组的技术、sFC都可以与CSTA有效结合进一步提高系统性能,提高IMS网络的服务质量。4)IMS业务逻辑触发机制方面:提出了业务逻辑触发的概念,提出了一种SIP应用服务器业务逻辑触发机制,详细定义了业务逻辑触发数据,给出了业务逻辑触发算法(Service Logic Triggering Algorithm,SLTA)。对基于SLTA的多业务逻辑环境下业务触发和无SLTA的原3GPP业务触发的性能对比分析表明,基于SLTA的业务触发可以有效提高触发效率,在降低S-CSCF吞吐量的同时,提高了系统性能。同时该业务逻辑触发机制完善了IMS网络中的业务触发机制。更多还原

【Abstract】 With the evolution of communication networks, the requirement of the services provided becomes much higher than before. As IMS (IP Multimedia Subsystem) enables 3G (Three Generation) network to be a full-service converging network, it is doubtlessly becoming the focus of technical research. The success of an IMS network depends on the variety and QoS (Quality of service) of its services. A QoS guarantee must provide fast and effective service triggering support. Service triggering includes ATA (Application Triggering Architecture), STD (Service Triggering Data), STA (Service Triggering Algorithm) and STP (Service Triggering Protocol), etc. This thesis concentrates on the research of IMS service triggering, involving: 1. ATA, focusing on the research on the application triggering architecture enhancement and proposing a new ATA to solve the problem of existing ATA; 2. STD, focusing on the research on the existing 3GPP (3rd Generation Partnership Project) service triggering data, analyzing its problems and proposing a Service-Key based service triggering data; 3. STA, focusing on the research on the triggering performance, analyzing the performance problems of the exsiting 3GPP STA and proposing several optimized service triggering algorithm to improve the performance of the IMS service triggering system;4. SLT (Service Logic Triggering), analyzing the nonstandard part of the 3GPP specification, proposing an SLTM (Service Logic Triggering Mechanism) of SIP AS (Application Server) and studying the performance of the IMS service triggering based on SLTMThe principal contributions of the work presented in this thesis are:1) ATA in IMS: In the exsiting 3GPP ATA, the 3GPP has only defined and implemented the iFC (nitial Filter Criteria). 3GPP has also defined the sFC (subsequent Filter Criteria), but given no implementation. To solve this problem and enhance the existing 3GPP ATA, a SIP (Session Initiation Protocol) header based implementation of sFC is proposed, which can effectively control the triggering of subsequent SIP messages and increase the routing flexibility of subsequent SIP messages;The service triggering based on iFC and sFC is analyzed, which is lack of flexibility and exists unnecessary service triggering. To solve the problem of the extra signaling traffic load of S-CSCF and AS and network processing delay caused by the unnecessary service triggering, a CATA (Call-state based ATA) is proposed. After illustrating how to trigger a service in CATA, the relationship of iFC, sFC and cFC (call-state based Filter Criteria) is discussed.2) STD in IMS: To solve the problem of the exsiting 3GPP service triggering data, a SIP header based implementation of Service-Key is proposed. By expanding the new Service-Key data, the following advantages are achieved: a) S-CSCF and AS can finsish the service/service logic triggering in an simple and effective way and improve the performance of service triggering; b) the conflict of iFC between new services and old ones when deploying new services is solved; c) the multiple services are triggered by the S-CSCF at one time becomes true.3) STA in IMS: After the performance of iFC based service triggering algorithm which is proposed by the 3GPP is studied, three STAs are proposed to improve the performance of the service triggering: a) Based on the proposed implementation of sFC, a NDSTA (New Dynamic STA based on iFC and sFC) is proposed. Performance analysis indicates that NDSTA can efficiently reduce the signaling traffic load of the S-CSCF and AS, increase the throughput of the system and significantly reduce the session setup delay. b) A GSTA (Group based STA) is proposed. In GSTA, the S-CSCF can trigger a group AS/service to reduce the times of service triggering and further decrease the signaling traffic load of the S-CSCF and improve the throughput and performance of the S-CSCF. c) In CATA, a CSTA (Call-state based STA) is proposed. Performance analysis indicates that CSTA is a flexible and effective STA. And the technology of AS/service grouping and sFC can be integrated into the CSTA to futher impove the system performance and the Qos of IMS.4) SLTM in IMS: The concept of service logic triggering and SLTM (Service Logic Triggering Mechanism) of SIPAS are proposed. In SLTM, the detailed service logic triggering data is defined and a SLTA (Service Logic Triggering Algorithm) is proposed. And then the performance compare between service triggering of multiple service logic environment with SLTA and the existing 3GPP service triggering without SLTA is performed. Performance analysis indicates that the service triggering with SLTA can considerably imprve the efficiency of service triggering, the throughput of the S-CSCF and the system performance. The proposed service logic triggering mechanism perfects service triggering mechanism in IMS, and provides guidance to the design of SIP AS from the perspective of service triggering in IMS network.更多还原