Research On The System Of Net Meeting Based On SIP

With the rapid development of Network Technology, the safeefficient economical Network Conference system has been more andmore widely adopted as a communication mode. Nowadays, NetworkConference is based on H.323 protocol stack, which hasshortcoming to some extent owing to its following the philosophyof traditional telecom systems, its complexity and itsexpansibility. The Session Initiation Protocol (SIP),constituted by IETF, has been defined as a signaling protocol forthe establishment, maintenance and termination of multimediasession between two or more users. It is now limited to signalingfor point-to–point real-time communication. SIP has receivedmore and more widely support from industry owning to its concisionits agility its easy implementation and its easy expansibility.Under the circumstance the Softswitch is to become the nextgeneration technology of network swithch, SIP is considered asthe kernel protocol in access layer of the Softswitch technology,and it has been successfully applied to several representativecommunication systems due to the interest of lots of famoustelecommunication companies. It is significant to research intothe Network Conference based on SIP for designing a NetworkConference on the IP network.This paper studies the conference framework in IP network,anew conference model based on the SIP proxy which can be used tosettle the expandability of the present conference framework andbring forward the concept of conference proxy between theconference servers and the user agents. The conference proxy canbe dynamically created according to the size of the conference,which makes the conference expandable. This paper defines thefunction of network elements such as Moderator, Conference server,Conference proxy and User agent. This paper also defines the basicprimitives between the network elements. Furthermore we extenda new SIP PROX method, analyses the field of the PROX method,fulfill the SIP PROX method and implement enhanced SIP ConferenceProxy based on the PROX method. As result, the conference proxycan keep the user'sate, the participants can be consistent witheach others, the system can improve the expandability of theNetwork Conference to break the bottleneck of conferencecontrolling on the IP Network. For the system of Vovida from Columbia University of the U.S.has provided a whole set of protocols whose design adopted theorient object method, and opened all its source codes incloudinga series of protocols as Sip RTP and so on, and VOCAL(Vovida OpenCommunicAtion Library)also has provided the detail documents andSDK packs for the users to develop secondly, it can be easilydeveloped new methods. From this point, we have carried out someresearch work in the system of Network Conference based on SIPon WINDOWS 2000 platform, the implementation of a part of thismodel was carried out by the tool VC++ 6.0 and based on analyzing...