Design and Implementation of Service Control Server in IMS-Based IPTV

IMS-based IPTV is an important research direction in next generation IPTV, in which Service Control Server (SCS) as an IMS application server is one of the most critical network entities. By the comparison of differences in behavior of various SIP entities, such as Proxy Server, Virtual User Agent (VUA), Back-to-Back User Agent and Redirect Server, combined with the characteristic of different IPTV services, such as Broadcast, Content on Demand (CoD), Time-shift Television, and network-side Private Video Record, some suggestions have been given on how to choose the SIP entities for SCS. After that, a general layered architecture for SCS has been designed, which can be used for different SIP entities, especially a modification has been made for VUA with the signaling and media function integration. Based on the analysis of SIP signaling and RTSP media control flows, the service state machine on the top layer in SCS has been designed through the mapping relationship of session event and service logical states. Further more, taking the CoD service as an example, we implement a SCS prototype and the technical feasibility has been verified.