摘要
随着通信网络在生产、生活中发挥着越来越大的作用,现代信息社会对通信网络的接入系统、交换系统、传输系统等相关领域人才的需求量增大。传统高校通信学科教育由于缺乏通信网络的实训平台,无法全面开展整个教学过程中的实践环节。
本文所依托的通信实训系统正是为解决此问题而设计,构建了可以模拟实际通信网络的小型通信网和配套的实训管理软件系统。该实训平台设备采用主流在网运行的通信设备,包含了SDH,软交换,无线通信等几个子系统,能够完全满足通信网络专业各方向的教学实验要求,帮助高校建立一流的通信网络实验室,结合理论概念培养学生实际动手的能力。
本文主要讨论了通信实训系统的软件设计与实现,作者的主要研究工作如下:
(1)介绍了通信网络实训系统的基本概念特点,给出了系统的整体硬件组成结构和几个子系统的拓扑结构设计与组网方法。
(2)通信网络实训系统软件系统的设计与实现:设计时将系统定位为基于RMI技术的小型C/S分布式系统,参照RUP软件开发过程,借助UML建模工具建立系统模型;进行需求分析,根据主要用例进行类设计,然后将系统结构分为视图、模型、控制器三个主要模块分别进行设计与实现。
(3)基于客户端缓存的设计与实现:针对过多重复远程调用会影响分布式系统性能和效率的问题,本文给出了一种基于客户端缓存的RMI方法,使用客户端本地缓存保存使用过的存根和结果,经过性能比较可以发现客户端缓存的加入能有效减少重复RMI调用的次数,从而提高程序响应速度并减少占用的网络带宽。
(4)总结并分析了系统有待进一步改进和完善的问题,对今后工作进行展望。
本文设计与实现的通信网络实训系统已通过青岛科技大学等高校的验收并投入实用,在实际的教学和实验中取得了良好效果。
With the communication network playing an increasingly important role in our production and life,Modern information society has a increased demand for qualified personnel in access system,switching system,transmission system,and other related fields.But due to lacking of communication networks training platform,it is always unable to fully carry out the process of practice session in traditional college communication education.
The communication network training system is designed to precisely solve the problem above.It is been constructed with mainstream communication facilities and necessary management software system as a small communication network to simulate the actual communication network.The system contains several sub-systems like SDH,soft exchange,wireless communication etc.It can completely satisfy the need of teaching and experiment of various communication subjects,and help the university to build the first-class communication network laboratory,raise student's ability of applying theory to reality.
This article mainly discussed the design and implementation of the communication network training system software based on RMI cache method, author's main research work is as follows:
(1)The basic concept of the communication network training system is introduced and then we present the system's overall hardware composition structure and topologies design of its several sub-systems.
(2)Refers to the RUP software development process,with the aid of the UML modeling tool,the system is design as a small C/S distributional architecture system on RMI technical,and the system's model is established.We first carry on the demand analysis,according to mainly use cases we design the classes,and then divide the system structure into three main parts:the view,the model,the controller. These modules are designed and realized then.
(3)In practice too many repeated remote method invocations may affect the performance of application.The paper gives a method for RMI based on client side cache.A client first query in local cache whether there is the stub or result the client tries to invocate,and if they exist the client will directly use them without further remote method call through the network.The performance comparison shows that the method improves the performance of RMI by decreasing repeated invocation times and reducing network bandwidth occupied.
(4)Summarizes,proposes and analyzes some problems of the system that need to be improved further.Carry on the forecast to the future work.
The system has already been in use in the Qingdao Scientific and technical university and other several universities.It has obtained good feedback on the actual teaching and experiment.
引文
[1]李昊.浅谈通信专业学生的培养[J].教育与职业,2007(09):108-109
[2]邓月明,王玲,周志彬.现代通信实训平台建设与实验教学改革[J]实验室研究与探索2007(12):122-124
[3]段景山,毛玉明.综合通信系统实验平台建设[J]实验科学与技术,2005,(S1):187-193
[4]戴亮,方晓勤,李丽.一种新的基于序列化的Java RMI方法[J]计算机工程,2006(22):99-101
[5]B.TopoI,M.Ahamad,and,J.Stasko.Robust State Sharing for Wide Area Distributed Applications[C],Proc.Int'l Conf.Distributed Computing(ICDCS),IEEE Computer Society,LosA lamitos,Calif.,1998:554-561
[6]Vijaykumar Krishnaswamy,Dan Walther,Sumeer Bhola,Ethendranath Bommaiah George Riley Brad Topoi.Efficient Implementation of Java Remote Method Invocation (RMI)[C].4th USENIX Conference on Object-Oriented Technologies and Systems,April 27-30,1998:1-23
[7]李文军,周晓聪,李师贤.分布式对象技术[M].机械工业出版社,2003
[8]雷军环,孟益民,厉亚.CORBA在三层客户机服务器模型中的应用[J]计算机工程与科学,2003(3)
[9]Tao Y,Jun O,Nakamura A,et al.Concept Design of Remote Fault Diagnosis System for Autonomous Mobile Robots[C].Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems,2000:931-936
[10]李一宁,汪泉弟,何为.基于C/S和B/S混合模式的电能管理信息系统[J]重庆大学学报,2003(06)
[11]孙卫琴.Java网络编程精解[M].电子工业出版社,2007.
[12]朱其亮,郑斌.CORBA原理及应用[M]北京邮电大学出版社,2001.
[13]Fintan Bolton Pure Corba[M]Sams,2001.
[14]John Cadman,Waite Group,and Chris Corry.Waite Group's COM/DCOM Primer Plus[M].Sams,1998
[15]David Iseminger.COM技术[M]机械工业出版社,2002
[16]Emmerich,W.Kaveh.Component technologies:Java beans,COM,CORBA,RM1,EJB and the CORBA[C].component model Software Engineering,2002.ICSE 2002.Proceedings of the 24rd International Conference on 2002:691-692
[17]杨喜敏,陆际光,唐菀.分布式应用技术中的CORBA、Java RMI和DCOM[J]中南民族大学学报(自然科学版),2002(02):61-67
[18]刘丹,程晓,侯德林.一种基于RMI的分布式架构设计[J]计算机应用与软件,2007(09):206-208
[19]Sun Microsystems.RMI Whitepaper[EB/OL].http://Java.sun.com/Javase/technologies/core/basic/rmi/whitepaper/index.jsp
[20]Ahuja,S.P.Quintao.Performance evaluation of Java RMI:a distributed object architecture for Internet based applications Modeling[C].Analysis and Simulation of Computer and Telecommunication Systems,2000.Proceedings.8th International Symposium on 2000.8:565-569.
[21]Elliotte Rusty Harold.Java网络编程[M].中国电力出版社,2005
[22]杜风雷 用RMI开发基于Java的分布式应用[J]微电子学与计算机2006(07):72-75
[23]苏洋.Java分布式应用程序设计[M].希望电子出版社,2002
[24]Elisabeth Freeman,Eric Freeman,Bert Bates,Kathy Sierra.Head First Design Patterns [M].O'Reilly Media,Inc:1 edition,2004
[25]赵卓,赵欣.RMI的分布式对象技术研究[J].微计算机信息,2006(09):231-233
[26]William Grosso.Java RMI[M].O'Reilly Associates.Inc,2001
[27]Graig Larman.UML和模式应用.第二版.机械工业出版社,2004
[28]Joseph Schmuller.UML基础、案例与应用.人民邮电出版社,2002
[29]Per Kroll,Philippe Kruchten.The Rational Unified Process Made Easy:A Practitioner's Guide to the RUP[M].Addison-Wesley Professional,2003
[30]阎宏.Java与模式[M].电子工业出版社,2002
[31]曹爽,贾素玲.MVC架构模式在C/S系统中的应用[J]电脑知识与技术(学术交流),2007(10):946
[32]曹大有,徐艳玲.基于RMI的MVC分层多机系统编程的实现[J].计算机系统应用2007(05):78-81
[33]王伟,贾慧娟.基于MVC模式的分布式作战指挥系统研究[J].微计算机信息,2007(30):50-52
[34]孙学康,毛京丽.SDH技术[M].人民邮电出版社,2003
[35]王英.程控交换机常见故障浅析[J].铁道通信信号,2005(11):40-41
[36]郭庆东,傅永根.无线市话PHS的组网技术[J].电力系统通信,2005(26):69-71
[37]Bruce Eckel.Java编程思想.第三版.北京:机械工业出版社,2005
[38]Esmond Pitt(Author),Kathleen McNiff Java.rmi:The Remote Method Invocation Guide Addison-Wesley Professional 2001
[39]Daniel Hagimont,Fabienne Boyer.A configurable RMI mechanism for sharing distributed Java objects[J].IEEE Internet Computing 2001,5(1):36-40
[40]李三红,吴永明,马云龙.基于Java RMI计算模型的智能查询技术的设计与实现[J].计算机应用与软件,2005(2):122-123
[41]cay s.horstmann,gary comell.JAVA2核心技术[M].机械工业出版社,2006
[42]Seong-Eun Chu,Dae-Wook Kang,Jae-Nam Kim.Efficient Implementations of Remote Method Invocation Considering Object Consistency[C].Cheju Island,Korea:Proceeding of IEEE Conference on Hybrid Information Technology,2006.634-641