在SGSN侧GTPC协议的设计、实现和测试

【作者】 涂小勇；

【导师】 杨余旺；

【作者基本信息】 南京理工大学 ， 模式识别与智能系统， 2004， 硕士

【摘要】 第三代移动通信系统(3G)是一种能够提供多种类型和高质量的数据业务、能实现全球无缝覆盖、具有全球漫游能力、与固定网络互连互通并以小型便携式终端在任何时候与任何地点进行任何类型的通信系统。作为3G的候选方案之一，通用移动通信系统(UMTS)采用宽带码分多址作为其无线传输技术。UMTS核心网兼容全球移动通信系统(GSM)。由于GSM在世界范围内的主导地位，GSM向UMTS的过渡将是2G向3G过渡的主要方式。 GSM以传输话音和低速数据业务为目的，基于电路交换(Circuit Switched，CS)，而UMTS致力于提供多种类型和带有服务质量(Qos)的业务，这些业务既可以是基于电路域的也可以是基于分组域的。为实现核心网从GSM向UMTS的平滑过渡，引入了通用分组无线业务(GPRS)，在电路交换的基础上，增加了分组交换(PacketSwitched，PS)模式。为了支持基于分组域的业务，增加了两个网络功能实体(Network Entity)：SGSN(服务的GPRS支持节点)与GGSN(网关GPRS支持节点)。 为了支持MS能接入多种网络中的应用业务，SGSN与GGSN之间的通讯通过GPRS隧道协议(GTP)，GPRS隧道协议可以封装多种类型的数据包，比如IPV4、IPV6和PPP等协议的数据包，这样MS能够通过UMTS网络访问多种类型网络。 本课属于中兴通讯南京分公司3G SGSN与GGSN项目组，主要依据3GPP2(Third Generation Partnership Project 2)2003年12月发布的R4协议29.060v4.10.0(2003-12)，结合测试开发的实践，在SGSN侧实现R4版本的GTPC协议。首先，作为背景知识，简单介绍了UMTS网络和GTPC协议。然后，对系统的总体设计思路做了一个介绍：采用多任务方式，任务间采用消息队列的通信方式，每个任务拥有自己的消息队列。消息驱动任务的运行，任务再把相应的消息分发到相应的独立通讯进程，独立通讯进程具体处理消息。这种设计方式降低了消息处理之间的耦合，使系统流程清晰，层次化和模块化好，如果要增加一个模块的功能，只需要增加相应的消息处理函数，特别适合增量开发方法和不断变化的协议版本。接着，具体讨论SGTPC模块的设计和实现。对SGTPC模块按照2.5G和3G完全合一的原则进行设计，向下完全兼容2.5G的GTPC，其重点是接口设计和消息的封装及可靠性传输。最后，对SGTPC模块进行了一个细致的单元测试。更多还原

【Abstract】 3G mobile communication system can provide many kinds of data services with Qos to subscribers that communicate with each other or with users access to fixed network by using mobile station anywhere and anytime. As a family member of 3G, UMTS adopts WCDMA as its radio transmission technology. In UMTS, core network is compatible with GSM. Because of the domination of GSM in the world, the evolution from GSM to UMTS is the main step from 2G to 3GAs a circuit switched System, GSM aimed at voice and low speed data while UMTS provides high speed data services with Qos which is either packet switched or circuit switched. For the smooth transition from GSM to UMTS, GPRS is involved in. It adds packet switched mode. To support packet switched mode, UMTS adds two network entities: SGSN and GGSN.GSNs communicate with each other by using GTP which can encapsulate many kinds of PDU such as IPV4, IPV6, PPP and so on. MS can access to varities of network by using GTP.This discourse appointed by 3G SGSN and GGSN project team of ZhongXing Communication Corporation is based on 3GPP2 R4 protocols released in December 2003 and the author’s test and work experience to design and implement GTP control plane protocol. First, as a background of this discource, UMTS system and GTP protocol are introduced. Second, it analyses a total outline of system designment which adopts multi-task. Tasks who owner itself a message queue communicate with each other by using message and are drived by message. It also assigns message to approprivate process which deal with message. This mode of designment make message’s processing independence,program flow simple and logical structure clarity. It is very fit for designment and implement of continually variable version of protocols. Third, it discusses to design, implement and test detailedly GTP control plane protocol in SGSN. GTP control plane protocol is designed according to syncretism of 2.5G and 3G , interface designment and message encapsulation is thought over. Finally, GTP control plane protocol in SGSN is tested carfully by using unit test.更多还原