The Real Time Streaming Protocol@ or RTSP@ is an application-level protocol for control over the delivery of data with real-time properties. RTSP provides an extensible framework to enable controlled@ on-demand delivery of real-time data@ such as audio and video. Sources of data can include both live data feeds and stored clips. This protocol is intended to control multiple data delivery sessions@ provide a means for choosing delivery channels such as UDP@ multicast UDP and TCP@ and provide a means for choosing delivery mechanisms based upon RTP (RFC 1889).