Research And Implementation Of SIP Protocol Based On 3G Intelligent Terminal

3GPP (3^rd generation parternship project) working group has decided to take SIP as the key protocol of IMS (IP Multimedia Subsystem). The goal of SIP is to provide everywhere access for all the successful services provided by Internet and make the Internet world seamless to the cell world. The services provided by 3G cannot take effect without intelligent terminals. This thesis mainly focuses on implementation of SIP application on Symbian OS—a Presence Agent that compliant to RFC3856 and verification of the whole system behaviors on emulator.The first part of the thesis first tells the architecture and functianality of 3G intellegent terminal and after comparing three popular operating systems of smart phones comes out the decision to use Symbian OS as the development platform. After that, it introduces the pitfalls of hardware that Symbian OS is based on and how it designed to comquer such problems. Then summarizes its software achiteture and points out the difficulties and laborious cost in developing. After introducing Symbian OS, the thesis is trying to provide detailed information on SIP (Session Initiation Protocol): its basic capabilities, SIP network components and also SIP message flows examples. Then describes Presence System, introduces the concept of Presence Agent, construction of Presence System and message flows between Presence components.The second part first summarizes study of open source project 'eXosip' protocol stack—how the four finite state machines work and implemented, how the stack send messages and its functions invoking flows, how the stack handles incoming messages and how the releated fsm state changes. With the help of further understanding and analysis on open source project 'eXosip', 'eXosip' is ported successfully from Windows to Symbian OS. And give an example on how to implement and design a multithread application into AO-based Symbian application. Presence Agent that compliant to RFC3856 is designed and implemented based on such SIP stack. After that, the PA is verified with emulator and comes out the conclusion that it meets the requirements of RFC3856.