The Research And Implementation Of SIP-based VoIP Applications In Wireless LAN

This paper introduced the concept of VoIP, the advantages and the specific means for realizing of VoIP. Then the current two main VoIP standards and their own characteristics were compared. At the same time, the Wireless LAN technology and the major wireless LAN standards were described.On this basis, this paper introduced the IEEE802.11b standards and the network topology, describes the main elements of the SIP protocol and SIP-based VoIP network topology posed by the major SIP components. Then the Similarity of the two topologies was researched. And it is discussed that developing a integrated network equipment which set of SIP proxy server and wireless access point function in it and using it as a key equipment for the SIP-based VoIP applications in Wireless LAN.In the third part, the specific design of the integrated equipment gave a detailed briefing, which included the introductions of equipment's internal structures, the main system, the important modules, the distribution system, emergency system, and upgrading systems, hardware principle. In the important modules introduction, this paper focused on the SIP proxy server module and MVC module. The MVC module introduction main included MVC's location in memory, MVC's implementation process, data frame management and so on. The SIP proxy server module introduction main included RTP and RTCP module, software process design and starting method.Finally, this paper presents two SIP-based VoIP solutions in Wireless LAN which using this kind of integrated network equipment. One is in campus, the another is in office buildings.In the appendix, the demonstration steps and the using method of software SIP phone were discussed.