在SGSN侧GTPC协议的设计、实现和测试
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。
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 3G
As 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 encapsul
ation is thought over. Finally, GTP control plane protocol in SGSN is tested carfully by using unit test.
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。
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 3G
As 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 encapsul
ation is thought over. Finally, GTP control plane protocol in SGSN is tested carfully by using unit test.
引文
[1]Hasson Gomaa．并发与实时系统软件设计．北京：清华大学出版社，2000
[2]Jean J．Labrosse．嵌入式系统构件．北京：中国电力出版社，2002
[3]Tero Ojanpera，Ramjee Prasad．宽带CDMA：第三代移动通信技术．北京：人民邮电出版社，2001
[4]Ron Patton．软件测试．北京：机械工业出版社，2002
[5]王伯雄．测试技术基础．北京：清华大学出版社，1999
[6]孔祥营，柏桂枝．嵌入式实时操作系统VxWorks及其开发环境．北京：中国电力出版社，2002
[7]探矽工作室．嵌入式系统开发圣经．北京：机械工业出版社，2003
[8]王学龙．嵌入式VxWorks系统开发与应用．北京：人民邮电出版社，2004
[9]宋茂强．通信软件设计基础．北京：北京人民出版社，2004
[10]赵会群．通信软件测试技术基础．北京：人民邮电出版社，2004
[11]莫多平，文灏，芙蓉，马明．3G核心网软件体系架构及其关键技术概述．计算机与数字工程，2003．3：44～46
[12]钱静，酆广增．移动通信系统从1G到4G的演进．江苏电信技术，2001．12：36～39
[13]黄杰，张力军．第三代移动通信网的QoS研究．软件学报，Vol．23．No．1．2003：28～32
[14]李明．移动核心网络的演进．电信技术，2002．10：17～19
[15]3GPP TS 23.060 V4.9.0 (2003-12) General Packet Radio Service (GPRS) Service description(Release 4)
[16]3GPP TS 29.060 V4.10.0 (2003-12) General Packet Radio Service GPRS Tunnelling Protocol (GTP) across the Gn and Gp Interface (Release 4)
[17]GSM 09.60 V7.5.1 (2000-12) General Packet Radio Service GPRS Tunnelling Protocol (GTP) across the Gn and Gp Interface (Release 1998)
[18]3GPP TS 25.413 V4.0.0 (2001-03) UTRAN Iu interface RANAP signaling(Release 4)
[19]3GPP TS 29.061 V4.10.0 (2003-12) General Packet Radio Service (GPRS); Interworking between the Public Land Mobile Network (PLMN) supporting GPRS and Packet Data Networks (PDN)(Release 4)
[20]ZXW-10CN测试部．3G核心网测试指南．内部资料，2000
[21]吴瑟．ZXWN SGSN GGSN子系统SGTPC概要设计说明(GTPV0)．内部资料，2000
[22]金友兴．ZXW-10CN SGSN总体设计．内部资料，2000
[23]ZXW-10CN支撑组．ZXWN(V3)操作系统软件子系统接口规范．内部资料，2003
[24]中国移动．中移WCDMA核心网测试规范．内部资料，2002
[2]Jean J．Labrosse．嵌入式系统构件．北京：中国电力出版社，2002
[3]Tero Ojanpera，Ramjee Prasad．宽带CDMA：第三代移动通信技术．北京：人民邮电出版社，2001
[4]Ron Patton．软件测试．北京：机械工业出版社，2002
[5]王伯雄．测试技术基础．北京：清华大学出版社，1999
[6]孔祥营，柏桂枝．嵌入式实时操作系统VxWorks及其开发环境．北京：中国电力出版社，2002
[7]探矽工作室．嵌入式系统开发圣经．北京：机械工业出版社，2003
[8]王学龙．嵌入式VxWorks系统开发与应用．北京：人民邮电出版社，2004
[9]宋茂强．通信软件设计基础．北京：北京人民出版社，2004
[10]赵会群．通信软件测试技术基础．北京：人民邮电出版社，2004
[11]莫多平，文灏，芙蓉，马明．3G核心网软件体系架构及其关键技术概述．计算机与数字工程，2003．3：44～46
[12]钱静，酆广增．移动通信系统从1G到4G的演进．江苏电信技术，2001．12：36～39
[13]黄杰，张力军．第三代移动通信网的QoS研究．软件学报，Vol．23．No．1．2003：28～32
[14]李明．移动核心网络的演进．电信技术，2002．10：17～19
[15]3GPP TS 23.060 V4.9.0 (2003-12) General Packet Radio Service (GPRS) Service description(Release 4)
[16]3GPP TS 29.060 V4.10.0 (2003-12) General Packet Radio Service GPRS Tunnelling Protocol (GTP) across the Gn and Gp Interface (Release 4)
[17]GSM 09.60 V7.5.1 (2000-12) General Packet Radio Service GPRS Tunnelling Protocol (GTP) across the Gn and Gp Interface (Release 1998)
[18]3GPP TS 25.413 V4.0.0 (2001-03) UTRAN Iu interface RANAP signaling(Release 4)
[19]3GPP TS 29.061 V4.10.0 (2003-12) General Packet Radio Service (GPRS); Interworking between the Public Land Mobile Network (PLMN) supporting GPRS and Packet Data Networks (PDN)(Release 4)
[20]ZXW-10CN测试部．3G核心网测试指南．内部资料，2000
[21]吴瑟．ZXWN SGSN GGSN子系统SGTPC概要设计说明(GTPV0)．内部资料，2000
[22]金友兴．ZXW-10CN SGSN总体设计．内部资料，2000
[23]ZXW-10CN支撑组．ZXWN(V3)操作系统软件子系统接口规范．内部资料，2003
[24]中国移动．中移WCDMA核心网测试规范．内部资料，2002