In order to describe clearly about the whole flow of conference control we introduce petri network to tell how the control unit works . in the end of this article we discuss some useful techniques to resolve security problem which are also very important in the system 通过rtp rtcp封包解包的设计实现对网络的流量控制，其中实现了漏桶算法的思想，并给出rtp rtcp组帧的流程；文章还对视频会议系统所面临的安全问题进行简单的分析并概括了一般的实现方法。
