The Implementation And Application Of The SIP Based Instant Messaging System

Along with the network technology's development and the network's popularization, thenetwork has been prevailing. Network can provide many functions such as working,recreation and communication for the people by means of Network Services. According to thestatistics, the network has become the industry with the most influence, the most rapidprogress and the most potential. It influences the development of nation's economy and theprogress of society deeply.However the network's rapid development also causes the people's demands for thenetwork more and more, people want to get facile and all-sided service, single networkservice is difficult to satisfy the needs. For example, Instant Messaging system, which is usedto be an instant and text-based electronic communication tool, has become an electroniccommunication system which includes individual space, games, news, community, Blog,multimedia telephone and multimedia conference. Thus the trend of services' composition isinevitable.As the provider of network service, it is evidence that they don't want to develop a newservice system when another function needs to be added in the network service. So, how todevelop a re-used and extensible network service system and how to implement the services'composition are very important.At the same time, the service conflict is inevitably when the services composition occurs.Therefore the service conflict's avoidance, examination and the resolving have become thehot spot that the researchers study on.Based on the task "A SIP based multimedia conference system", which is offered by thenext generation Internet China and Japan IPV6 cooperation project (IPv6-CJ), this thesisconstructs the IP network video conference system and instant message system based onSession Initiation Protocol (SIP), uses SIP's characteristic to implement the composition ofmultimedia conference system and the instant message system and resolves the conflict of thecomposition between video conference system and instant message system.At first the thesis simply introduces the SIP protocol. SIP is defined by IETF, based on anIP application level controlling protocol. SIP is the signal protocol based on the plain text, itmay manage the session in different network accesses. Because SIP is a service creationplatform, the system based on SIP has the advantage of component reusage and can use theexisting frame to provide new services.Then the thesis describes the SIP based video conference system in details, presents howto design, develop and implement the system as the service creation platform. And based onthe reusage and scalability of the SIP system, this thesis shows how to implement thecomposition of the instant message system and the video conference system with the premiseof smallest modificationNext,concerning to the conflict in the composition of the video conference system andthe instant message system, the thesis analyses the service conflict , utilizes the Web Servicestechnology to facilitate the communication between different platforms and between differentlanguage , proposes a method using the Web Services technology to resolve service conflict.With the rapid development of network services today, the article finally carried on thediscussion how the presence service can fully play its role as a fundamental service.