 plane has been implemented, as shown in Figure 2.14. As a proof of concept, related to the media plane, VideoLAN has been used as a media server and a VideoLAN control interface has been implemented (VideoLAN Service Control). Related to the control plane, a driver for the VideoLAN Control Service and a transcoding service have been implemented, based on states machines. After that, they have been deployed on a SIP Application Server. As a result, © 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security Media plane VideoLan control service SIP-CMI subsystem Media server SIPuser@i2cat.net VideoLan Control plane SIP_UA Transcoding service driver RTP/UDP flow Service media provider controller FIGURE 2.14 Transcoding service implemented on the SIP-CMI platform. the transcoding module has become a video on demand HDV system. Current video on demand HDV systems [28] solve this control of the server by using Web applications to initiate a video stream from the transmitting unit to the receiving unit, with VideoLAN. 2.7.2 SIP Infrastructure SIPCAT is a value-added services integrated platform based on SIP. As Fig- ure 2.3 shows, this platform offers the main SIP components needed to develop the SIP-CMI approach. The main goal of this implementation is to offer a SIP test platform where a developer community (application service providers) and user community are testing SIP value-added services. The SIPcat platform offers advanced communication services of voice, video, and data using several communication protocols such as H.323, PSTN, H.320, 3G domains, and SIP gateways. All core components have been implemented using open source solutions and its core architecture has been enriched with components from commercial vendors, such as Radvision, Polycom, and Tandberg. The components that integrate this configuration are the classic elements of the SIP framework. Proxy Server and Registrar are implemented by OpenSer. Additionally, the management services guarantee the proper operation of the 