Research And Implementation Of Wireless SIP Server Based On ARM11

When facing frequent natural disasters and other major catastrophe, establishing asound emergency communications system is a research focus in communication field.The system should have those characteristics, such as working on without the existingcommunications systems, portable and deploying rapidly. The study of a portableemergency communications server is the core issue of the whole system. SessionInitiation Protocol (SIP) is a signaling protocol used to establish, modify, and terminateone or more multimedia sessions over IP networks. It is the simple and flexible featuresof SIP that has appealed to researchers’s interest. Now it has been the signaling protocolto provide IP multimedia services in the third generation of mobile systems (3G). Thus,the number of people is dramatically increased in knowing about SIP. At the same time,with the fast development of embedded technology, it is popular that embeddedcommunication equipment regard as a node or terminal among communication network.And the embedded system will benefit the communicate equipment on minimization. Tocombine with the characteristics of SIP protocol and embedded system, the paper focuson design an embedded Wireless-SIP server which has registered and routeing functions.Moreover, the users can use the server system to establish a local session by SIP softphone.The parper deeply analyses the architecture of SIP including the message format,the hierarchy and the basic function of various SIP entities. And then, the registeredprocess and the method to establish a call are also introduced. This is the theoreticalbasis of developing server. The parper also introduces the oSIP which is a source codeprotocol stack based on SIP and master a method to develop application program byanalyzing its realization on Syntax Encoding Module and State Machine Module indepth.To combine with the characteristics of hierarchy and SIP entities, the paper deignsa server based on oSIP under the Linux development environment. The server has manyfunctions, such as sending and receiving messages, certification, registration, proxy andupdating user registration information.Choosing the advanced ARM11development board as the hardware platform, theparper ports applications successfully and realizes the server system. In addition, this paper designes a variety of test model on usability and practicability testing of theserver system, and the server’s funtions has been proved successfully.