| Instant communication is a real-time interaction on Internet, it includes many forms, such as instant message, call, and so on. Now, Instant communication has become one of the most popular Internet application listed only after E-mail and Web. The network conference discussed in this paper is also one of forms of instant communication. It can implement a function that many users can communicate all together by text, voice and video. It's an application on multimedia, and has been used in instant communication and other independent systems, and is popular with users. However, the traditional schemes on network conference are limited for signaling control, capacity of terminals and bandwidth which aroused from its characteristic that communication are among many clients.This paper discusses the network conference. At first, it introduces and analyses the theories of SIP and IP multicast, and their advantages on controlling conference and distributing media data. Then, lists some basic models on network conference, and states their characteristics and shortages respectively. And puts forward the model of network conference based on SIP and IP multicast, expatiates its characteristics on technology and application, and states its advantages on controlling conference, alleviating load of terminals and utilizing bandwidth effectively. After that, designs an audio network conference system based on the model, that is, a concrete application model actually. This paper puts forward the main requirements of the system, and designs concrete controlling flows based on the requirements, and explains bottom procedure by some graphs on signal interaction. And then, states primary implement details of the audio network conference system, which include description on development environment, description on user interfaces newly designed, description on expansion for open source stack and explanation on main flows. At last, there are a summing-up and expectation about the research work. |
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