基于OSGI的面向服务插件框架研究与应用
|
摘要
随着软件技术和网络技术的快速发展以及复杂商业需求的不断演进,支持异构模块动态部署、增量式模块开发、运行时刻服务动态管理、敏捷性开发等软件架构技术已成为软件工程领域的研究热点,受到越来越多研究者的关注。本文首先在分析传统软件体系结构的演进过程以及SOA(Service-OrientedArchitecture)现状的基础上,针对SOA架构实施过程中存在的不足之处,提出了基于OSGI(Open Service Gateway Initiative)的面向服务插件模型OSPAM(OSGI Service-Plug Architecture Model)以及OSPAM的框架模板SPOF(service-Plug Oriented Framework),设计开发了一个基于SPOF框架的OMC(Operation＆Maintenance Center)系统。本文主要工作包括:
1.介绍了OSGI R4规范的详细定义以及OSGI核心思想在软件体系架构和企业集成领域的借鉴之处。通过传统体系结构与插件体系结构的对比,结合OSGI在插件式开发方面的卓越特点,提出了一种基于OSGI的面向服务插件模型OSPAM。该模型采用分层模式思想,将服务请求实体层SRE与资源实体层RE逻辑分离开来,服务注册管理层SRM为SRE和RE提供了统一的服务注册、路由、组合以及消息传递等机制。论文对SRM层、OSGI包装器、WS包装器、插件生命周期管理矩阵、插件协同机制等作了深入研究。该模型解决了业务场景变化与迭代式软件开发过程的矛盾,使得复杂商业需求与软件开发架构同步演进,有利于模块化软件开发过程的标准化,实现了即插即用的模块化管理,最大限度的降低了模块间的耦合性,使面向服务架构SOA获得更大程度的商业敏捷性。
2.在OSPAM模型基础上,结合SOA原始模型、OSGI微内核Equinox、Web Service、内存数据库、XML等技术,设计并实现了一个具体的面向服务插件框架SPOF。该框架由SPOF应用层、Bundle Context Cache、服务插件管理中心等构成。给出了在Web服务器与Servlet容器中嵌入Equinox的解决方案,分析研究了服务插件的调用方式、OSGI服务封装方法,并参考Eclipse的ExtensionRegistry技术给出SPOF框架的扩展设计。SPOF框架具有整体实现系统的可插拔性、动态改变系统行为性、资源服务细节无关性、模块依赖最小化等优点
3.针对目前在线计费OCS的子系统OMC监控维护多网元、多服务进程等业务需求,设计了基于SPOF框架的OMC系统,给出了OMC系统总体架构、基于SPOF的设计思想、业务场景展现、业务场景中的模块描述、业务流程定义、业务对象组成等的具体实现。
With rapid development of software and network technology and the evolvement of complicated commercial demand, the software infrastructure technology which can support module dynamic deployment, incremental module development, dynamic management of run-time service, and agile software development has become hotspots of current research in software engineering field as well as more and more attention from the researchers. At first, this article is based on the analysis of traditional software engineering evolvement and the current situation of SOA, with regard to shortcomings of current implement process of SOA architecture, a kind of OSGI Service-Plug Architecture Model (OSPAM) based on the OSGI Specification is proposed. What's more, a definite service-plug oriented framework (SPOF) based on OSPAM is designed and realized. As the result, the author uses the OMC (Operation & Maintenance Center) as an example to explain how to develop the application system based on SPOF. The main tasks involved in the paper are as follows:
1. The definition of OSGI R4 specification and useful references of OSGI core idea to software system architecture and EAI are introduced. Through the contrast of traditional software architecture and plug-in architecture, and combined with excellent characteristics of plug-in architecture, a kind of OSGI Service-Plug Architecture OSPAM model based on the OSGI was proposed. The model adopts the layer division thought, and separates the service enquiry substantiality layer (SRE) from resource substantiality layer (RE) logically. Meanwhile, SRE has provided an entity system for SRE and RE to register, route, combine and news transmit. In this research general structure of the module has been investigated, SRM(Service Register Management) layer, OSGI wrapper generation, WS wrapper generation, plug in lifecycle management matrix, and plug in synergetic mechanism have been introduced in detail, and especially emphasis on the event-handling implementation consideration of OSGI wrapper generation, WS wrapper generation and OSPAM module.
2. On the basis of OSPAM module, combined with the technology of SOA original module, OSGI micro-kernel Equinox, web services, memory database and XML, a definite service-plug oriented framework(SPOF) is designed and realized. This framework is consisting of SPOF application layer, Bundle Context Cache, distributed service management center and SPOF expansion. This article has provided the solution of imbedding Equinox in Web server and Servlet container. In addition, the article also analyses and researches the method of plug-in transferring way, OSGI and serving and encapsulating the method, net service to encapsulate the method of the plug-in package, the expansion that Extension Registry technology of consulting Eclipse provides SPOF frame is designed. SPOF frame has many merits as the whole implementation system that can realize the system plug-in function, change systematic behavior dynamically and minimize dependence on module, etc.
3. SPOF application framework based on OSPAM module is applied in the development of OMC system. As the result, the feasibility and practicability of its crucial technique is verified in this research. Based on the SPOF design philosophy, the business scene is represented; the module in the business scene is described and the definition of business procedure as well as the consisting of business target are realized.
1.介绍了OSGI R4规范的详细定义以及OSGI核心思想在软件体系架构和企业集成领域的借鉴之处。通过传统体系结构与插件体系结构的对比,结合OSGI在插件式开发方面的卓越特点,提出了一种基于OSGI的面向服务插件模型OSPAM。该模型采用分层模式思想,将服务请求实体层SRE与资源实体层RE逻辑分离开来,服务注册管理层SRM为SRE和RE提供了统一的服务注册、路由、组合以及消息传递等机制。论文对SRM层、OSGI包装器、WS包装器、插件生命周期管理矩阵、插件协同机制等作了深入研究。该模型解决了业务场景变化与迭代式软件开发过程的矛盾,使得复杂商业需求与软件开发架构同步演进,有利于模块化软件开发过程的标准化,实现了即插即用的模块化管理,最大限度的降低了模块间的耦合性,使面向服务架构SOA获得更大程度的商业敏捷性。
2.在OSPAM模型基础上,结合SOA原始模型、OSGI微内核Equinox、Web Service、内存数据库、XML等技术,设计并实现了一个具体的面向服务插件框架SPOF。该框架由SPOF应用层、Bundle Context Cache、服务插件管理中心等构成。给出了在Web服务器与Servlet容器中嵌入Equinox的解决方案,分析研究了服务插件的调用方式、OSGI服务封装方法,并参考Eclipse的ExtensionRegistry技术给出SPOF框架的扩展设计。SPOF框架具有整体实现系统的可插拔性、动态改变系统行为性、资源服务细节无关性、模块依赖最小化等优点
3.针对目前在线计费OCS的子系统OMC监控维护多网元、多服务进程等业务需求,设计了基于SPOF框架的OMC系统,给出了OMC系统总体架构、基于SPOF的设计思想、业务场景展现、业务场景中的模块描述、业务流程定义、业务对象组成等的具体实现。
With rapid development of software and network technology and the evolvement of complicated commercial demand, the software infrastructure technology which can support module dynamic deployment, incremental module development, dynamic management of run-time service, and agile software development has become hotspots of current research in software engineering field as well as more and more attention from the researchers. At first, this article is based on the analysis of traditional software engineering evolvement and the current situation of SOA, with regard to shortcomings of current implement process of SOA architecture, a kind of OSGI Service-Plug Architecture Model (OSPAM) based on the OSGI Specification is proposed. What's more, a definite service-plug oriented framework (SPOF) based on OSPAM is designed and realized. As the result, the author uses the OMC (Operation & Maintenance Center) as an example to explain how to develop the application system based on SPOF. The main tasks involved in the paper are as follows:
1. The definition of OSGI R4 specification and useful references of OSGI core idea to software system architecture and EAI are introduced. Through the contrast of traditional software architecture and plug-in architecture, and combined with excellent characteristics of plug-in architecture, a kind of OSGI Service-Plug Architecture OSPAM model based on the OSGI was proposed. The model adopts the layer division thought, and separates the service enquiry substantiality layer (SRE) from resource substantiality layer (RE) logically. Meanwhile, SRE has provided an entity system for SRE and RE to register, route, combine and news transmit. In this research general structure of the module has been investigated, SRM(Service Register Management) layer, OSGI wrapper generation, WS wrapper generation, plug in lifecycle management matrix, and plug in synergetic mechanism have been introduced in detail, and especially emphasis on the event-handling implementation consideration of OSGI wrapper generation, WS wrapper generation and OSPAM module.
2. On the basis of OSPAM module, combined with the technology of SOA original module, OSGI micro-kernel Equinox, web services, memory database and XML, a definite service-plug oriented framework(SPOF) is designed and realized. This framework is consisting of SPOF application layer, Bundle Context Cache, distributed service management center and SPOF expansion. This article has provided the solution of imbedding Equinox in Web server and Servlet container. In addition, the article also analyses and researches the method of plug-in transferring way, OSGI and serving and encapsulating the method, net service to encapsulate the method of the plug-in package, the expansion that Extension Registry technology of consulting Eclipse provides SPOF frame is designed. SPOF frame has many merits as the whole implementation system that can realize the system plug-in function, change systematic behavior dynamically and minimize dependence on module, etc.
3. SPOF application framework based on OSPAM module is applied in the development of OMC system. As the result, the feasibility and practicability of its crucial technique is verified in this research. Based on the SPOF design philosophy, the business scene is represented; the module in the business scene is described and the definition of business procedure as well as the consisting of business target are realized.
引文
[1]Jacobson,G.Booch,J.Rumbaugh.The unified software development process[M].Addison-Wesley,1999.
[2]Johnson RE,Foote B.Designing reusable classes[J].Journal of Object-Oriented Programming,1988,1(2):22-35.
[3]Firesmith D G.Frameworks:the golden path to object,Nirvana[J].Journal of Object-Oriented Programming,1994,7-8.
[4]Perry,D.E.Software engineering and software architecture[A].In:Feng,Yu-lin.Proceedings of the International Conference on Software:Theory and Practice[C].Beijing:Electronic Industry Press,2000.1-4.
[5]Mary Shaw,David Garlan.软件体系结构:一门初露端倪学科的展望(影印版)(M).北京:清华大学出版社,1998.
[6]Kruchten,P.B.The 4+1 view model of architecture[J].IEEE Software,1995,12(6):42-50.
[7]David Garlan,Dewayne E.Perry:Introduction to the Special Issue on Software Architecture[J].IEEE Transactions on Software Engineering,1995,21(6):12-14.
[8]Boehrn B.Engineering context,invited talk.In:Garlan D.Proceedings of the 1st International Workshop on Architecture for Software Systems Seattle.New York:ACM Press,1995.1-8.
[9]孙昌爱,金茂忠,刘超.软件体系结构研究综述[J].软件学报,2002,(07).
[10]Clements,P.C.,Weiderman.N.Report on the 2nd international workshop on development and evolution of software architectures for product families,Technique REport CMU/SEI-98-SR-003,Carnegie Mellon University,1998.
[11]Introducing Indigo:An Early Look.[EB/OL].http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/introin-digov.
[12]Schmidt M-T,Hutchison B,Lambros P,et al.The Enterprise Service Bus:Making Serviceoriented Architecture real[J].IBM Systems Journal,2005,44(4):781-797.
[13]Service-Oriented Architecture and Web Services:Concepts,Technologies,and Tools.http://java.sun.com/developer/technicalArticles/WebServices/soa2/JavaTechs.html.
[14]时亚弘,周铭.新一代Web应用服务器BEA WebLogic研究与开发指南[J].计算机应用研究,2002(8):138-139.
[15]SAP NetWeave Capabilities.https://www.sdn.sap.com/irj/sdn/netweaver.
[16]InterESB介绍.http://www.intervision.net.cn/Articleshow.asp?ArticleID=45.
[17]韩少春.基于EOS的电信BSS系统的设计和实现[D].山东大学,2006.
[18]BOA-信息化动力互联网引擎.http://www.tongtech.com/cpzs/cpzs.asp.
[19]李卫忠.东软UniEAP统一架构平台亮相[J].微型机与应用,2007,(08):17-18.
[20]Apusic Platform产品家族.http://www.apusic.com/product/esb.htm.
[21]李磊,王怀民.CORBA与EJB集成技术的研究[J].计算机科学,2001,(06):12-13.
[22]杨小枫,张志鸿.OMG的对象管理体系结构分析[[J].郑州大学学报,1999,31(2):17-21.
[23]王欣.分布式对象技术与CORBA[J].计算机工程,1997,23(1):245-247.
[24]Jon Siegel.A Preview of CORBA3[J].Computer,1999,5:114-116.
[25]黄为民.分布式对象构件及其应用[[J].计算机应用研究,2000,10(1):83-85.
[26]Landis S,Shapiro W.CORBA naming-Service evaluation[J].IEEE Concurrency,1999,7(4):44-51.
[27]Siegel J.OMG overview:CORBA and the OMA in enterprise computing[J].Communications of the ACM,1998,41(10):37-43.
[28]房鼎益,周兴社,康继昌.分布式构件交互机制研究[[J].西北大学学报,2002,20(3):392-395.
[29]张昭理,胡金柱.CORBA构件模型在分布式体系结构中的应用[[J].计算机工程,2004,34(12):81-83.
[30]张志伟,隋品波,郭长国,吴泉源.分布对象中间件异步消息的研究与实现[J].计算机学报,2004,(12):21-23..
[31]The Architecture of DCOM(N).Microsoft Whitepaper,1996:44-47.
[32]The Technical Overview of DCOM(N).Microsoft Whitepaper,1996:34-38.
[33]申德荣,于戈,寇月,聂铁铮应用于Web服务合成的一种有效的Web服务发现策略[J].小型微型计算机系统,2005,(10):16-17.
[34]YK Fei,ZJ Wang.A Concept Model of Web Component[C].In Proceeding of IEEE International Conference on Services Computing,2004,159-164.
[35]Tsalgatidou A,Pilioura T.An overview of standards and related technology in Web Service[J].Distributed and Parallel Databases,2002,12(2-3):135-162.
[36]Sillitti Alberto,VernazzaTullio,Succi Giancarlo.Service oriented programming:A new paradigm of software reuse[J].Lecture Notes in Computer Science,2002,269-280.
[37]徐罡,黄涛,绍华,叶丹.分布应用集成核心技术研究综述[J].计算机学报,2005,28(4):24-26.
[38]Michael N.Huhns,Munindar P.Singh."Service-Oriented Computing:Key Concepts and Principles"[J].IEEE Internet Computing,1999(9):75-81.
[39]Benatallah B,Dumas M,Fauvet M.Overview of some patterns for architecting and managing composite Web Service[J].ACM SIGecom Exchange,2002,3(3):9-16.
[40]Zou Ying,Kontogiannis Kostas.Web-based specification and integration of legacy Service.In:Proceedings of Advanced Study on Collaborative Research,Mississauga.Ontario,Canada,2000,17-25.
[41]Joseph Bih.Service Oriented Architecture A New Paradigm to Implement Dynamic E-business Solutions[J].ACM Ubiquity,2006,(7):5-7.
[42]World Wide Web Consortium(W3C)."Web Services Activity".http://www.w3.org/2002/ws/.
[43]L Lilan,H Yu'an,Y Tao,X Zonghui.REsearch on SOA-based Manufacturing Grid and Service Modes[C].The Sixth International Conference on Grid and Cooperative Computing 2007,608-613.
[44]Boris Lublinsky,Dmitry Tyomkin.Dissecting Service oriented architectures[J].Business Integration Journal,2003,(10):52-58.
[45]Bruce Lowenthal."Rules Evolution in Service-Oriented Architecture".http://www.ftponline.com/ea/magazine/spring2006/features/blowenthal/default_pf.aspx.
[46]杨芙清.软件工程技术发展思索[J].软件学报,2005,16(1):1-7.
[47]岳昆,王晓玲,周傲英.Web服务核心支撑技术:研究综述[J].软件学报,2004,15(3):428-442.
[48]Heather Kreger.Web Service conceptual architecture(WSCA 1.0).http://www-900.ibm.com/developerWorks/cn/WebService/ws-wsca/part3/index-eng.shtml.
[49]王建伟.基于Web Services的SOA架构设计方法的研究[D].大连海事大学,2006.
[50]Johnson W,Mudumbai S,Thompson M.Authorization and attribute certificates for widely distributed access control.In:IEEE Proceeding of the 7th Workshop on Enabling Technologies:Infrastructure for Collaborative Enterprises.Washington:IEEE Computer Society Press,1998,340-345.
[51]Open Services Gateway Initiative.OSGI Service platform[Z].Release 4,2006.
[52]OSGI联盟.Whitepaper.http://www.osgi.org,2004(7):10-11.
[53]马占锋,梁力,张玉军,赵秋霞.EAP与Diameter结合的认证机制设计与实现[J].计算机工程,2006,(13):32-33.
[54]北电网络.GPRS/WCDMA移动网智能计费解决方案[J].世界电信,2005,(12):15-16.
[55]杨抗,何方白,张溪.关于3GPP R5核心网规划的综合思考[J].移动通信,2007(09):21-23.
[56]庄严,时政.移动网络在线计费系统的演进方案[J].电信快报,2007(06):7-8.
[2]Johnson RE,Foote B.Designing reusable classes[J].Journal of Object-Oriented Programming,1988,1(2):22-35.
[3]Firesmith D G.Frameworks:the golden path to object,Nirvana[J].Journal of Object-Oriented Programming,1994,7-8.
[4]Perry,D.E.Software engineering and software architecture[A].In:Feng,Yu-lin.Proceedings of the International Conference on Software:Theory and Practice[C].Beijing:Electronic Industry Press,2000.1-4.
[5]Mary Shaw,David Garlan.软件体系结构:一门初露端倪学科的展望(影印版)(M).北京:清华大学出版社,1998.
[6]Kruchten,P.B.The 4+1 view model of architecture[J].IEEE Software,1995,12(6):42-50.
[7]David Garlan,Dewayne E.Perry:Introduction to the Special Issue on Software Architecture[J].IEEE Transactions on Software Engineering,1995,21(6):12-14.
[8]Boehrn B.Engineering context,invited talk.In:Garlan D.Proceedings of the 1st International Workshop on Architecture for Software Systems Seattle.New York:ACM Press,1995.1-8.
[9]孙昌爱,金茂忠,刘超.软件体系结构研究综述[J].软件学报,2002,(07).
[10]Clements,P.C.,Weiderman.N.Report on the 2nd international workshop on development and evolution of software architectures for product families,Technique REport CMU/SEI-98-SR-003,Carnegie Mellon University,1998.
[11]Introducing Indigo:An Early Look.[EB/OL].http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/introin-digov.
[12]Schmidt M-T,Hutchison B,Lambros P,et al.The Enterprise Service Bus:Making Serviceoriented Architecture real[J].IBM Systems Journal,2005,44(4):781-797.
[13]Service-Oriented Architecture and Web Services:Concepts,Technologies,and Tools.http://java.sun.com/developer/technicalArticles/WebServices/soa2/JavaTechs.html.
[14]时亚弘,周铭.新一代Web应用服务器BEA WebLogic研究与开发指南[J].计算机应用研究,2002(8):138-139.
[15]SAP NetWeave Capabilities.https://www.sdn.sap.com/irj/sdn/netweaver.
[16]InterESB介绍.http://www.intervision.net.cn/Articleshow.asp?ArticleID=45.
[17]韩少春.基于EOS的电信BSS系统的设计和实现[D].山东大学,2006.
[18]BOA-信息化动力互联网引擎.http://www.tongtech.com/cpzs/cpzs.asp.
[19]李卫忠.东软UniEAP统一架构平台亮相[J].微型机与应用,2007,(08):17-18.
[20]Apusic Platform产品家族.http://www.apusic.com/product/esb.htm.
[21]李磊,王怀民.CORBA与EJB集成技术的研究[J].计算机科学,2001,(06):12-13.
[22]杨小枫,张志鸿.OMG的对象管理体系结构分析[[J].郑州大学学报,1999,31(2):17-21.
[23]王欣.分布式对象技术与CORBA[J].计算机工程,1997,23(1):245-247.
[24]Jon Siegel.A Preview of CORBA3[J].Computer,1999,5:114-116.
[25]黄为民.分布式对象构件及其应用[[J].计算机应用研究,2000,10(1):83-85.
[26]Landis S,Shapiro W.CORBA naming-Service evaluation[J].IEEE Concurrency,1999,7(4):44-51.
[27]Siegel J.OMG overview:CORBA and the OMA in enterprise computing[J].Communications of the ACM,1998,41(10):37-43.
[28]房鼎益,周兴社,康继昌.分布式构件交互机制研究[[J].西北大学学报,2002,20(3):392-395.
[29]张昭理,胡金柱.CORBA构件模型在分布式体系结构中的应用[[J].计算机工程,2004,34(12):81-83.
[30]张志伟,隋品波,郭长国,吴泉源.分布对象中间件异步消息的研究与实现[J].计算机学报,2004,(12):21-23..
[31]The Architecture of DCOM(N).Microsoft Whitepaper,1996:44-47.
[32]The Technical Overview of DCOM(N).Microsoft Whitepaper,1996:34-38.
[33]申德荣,于戈,寇月,聂铁铮应用于Web服务合成的一种有效的Web服务发现策略[J].小型微型计算机系统,2005,(10):16-17.
[34]YK Fei,ZJ Wang.A Concept Model of Web Component[C].In Proceeding of IEEE International Conference on Services Computing,2004,159-164.
[35]Tsalgatidou A,Pilioura T.An overview of standards and related technology in Web Service[J].Distributed and Parallel Databases,2002,12(2-3):135-162.
[36]Sillitti Alberto,VernazzaTullio,Succi Giancarlo.Service oriented programming:A new paradigm of software reuse[J].Lecture Notes in Computer Science,2002,269-280.
[37]徐罡,黄涛,绍华,叶丹.分布应用集成核心技术研究综述[J].计算机学报,2005,28(4):24-26.
[38]Michael N.Huhns,Munindar P.Singh."Service-Oriented Computing:Key Concepts and Principles"[J].IEEE Internet Computing,1999(9):75-81.
[39]Benatallah B,Dumas M,Fauvet M.Overview of some patterns for architecting and managing composite Web Service[J].ACM SIGecom Exchange,2002,3(3):9-16.
[40]Zou Ying,Kontogiannis Kostas.Web-based specification and integration of legacy Service.In:Proceedings of Advanced Study on Collaborative Research,Mississauga.Ontario,Canada,2000,17-25.
[41]Joseph Bih.Service Oriented Architecture A New Paradigm to Implement Dynamic E-business Solutions[J].ACM Ubiquity,2006,(7):5-7.
[42]World Wide Web Consortium(W3C)."Web Services Activity".http://www.w3.org/2002/ws/.
[43]L Lilan,H Yu'an,Y Tao,X Zonghui.REsearch on SOA-based Manufacturing Grid and Service Modes[C].The Sixth International Conference on Grid and Cooperative Computing 2007,608-613.
[44]Boris Lublinsky,Dmitry Tyomkin.Dissecting Service oriented architectures[J].Business Integration Journal,2003,(10):52-58.
[45]Bruce Lowenthal."Rules Evolution in Service-Oriented Architecture".http://www.ftponline.com/ea/magazine/spring2006/features/blowenthal/default_pf.aspx.
[46]杨芙清.软件工程技术发展思索[J].软件学报,2005,16(1):1-7.
[47]岳昆,王晓玲,周傲英.Web服务核心支撑技术:研究综述[J].软件学报,2004,15(3):428-442.
[48]Heather Kreger.Web Service conceptual architecture(WSCA 1.0).http://www-900.ibm.com/developerWorks/cn/WebService/ws-wsca/part3/index-eng.shtml.
[49]王建伟.基于Web Services的SOA架构设计方法的研究[D].大连海事大学,2006.
[50]Johnson W,Mudumbai S,Thompson M.Authorization and attribute certificates for widely distributed access control.In:IEEE Proceeding of the 7th Workshop on Enabling Technologies:Infrastructure for Collaborative Enterprises.Washington:IEEE Computer Society Press,1998,340-345.
[51]Open Services Gateway Initiative.OSGI Service platform[Z].Release 4,2006.
[52]OSGI联盟.Whitepaper.http://www.osgi.org,2004(7):10-11.
[53]马占锋,梁力,张玉军,赵秋霞.EAP与Diameter结合的认证机制设计与实现[J].计算机工程,2006,(13):32-33.
[54]北电网络.GPRS/WCDMA移动网智能计费解决方案[J].世界电信,2005,(12):15-16.
[55]杨抗,何方白,张溪.关于3GPP R5核心网规划的综合思考[J].移动通信,2007(09):21-23.
[56]庄严,时政.移动网络在线计费系统的演进方案[J].电信快报,2007(06):7-8.