In The The Sgsn The Side Gtpc Agreement Design, Implementation And Testing

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.