The design and implementation of sip control for Multimedia Conference system

In order to implement basic communication capabilities for Multimedia Conference, we choose SIP protocol which is very popular recently years as our communication protocol, we have used SIP protocol to implement many functions about conference. We choose the reciprocate SIP stack to implement these functions. In order to use this stack, we need to design and implement SIP signal control to manage the SIP stack. The SIP Control layer plays a role of connecting link between the upper layer (multimedia conference logic module) and the lower layer (SIP stack). In this article we will give a brief introduction about this layer, we will introduce three module in this layer, SIPHandler module, SIPController module and ControlThread module, at last we will experience an example about 3PCC.