The growth of the Internet has provided the ability to share, communicate, and preserve more communications than ever. Real-Time Streaming Protocol (RTSP) was developed in the late 1990s, and is a foundation for the current convergence of communications. RTSP provides applications the ability to stream voice and video using standard VCR-like controls such as "play" or "pause." A quick look at QuickTime, Windows Media Player, RealPlayer, MPEG4IP, and Skype show how widespread RTSP has become.
As with all IP-based telecommunications, RTSP is susceptible to jitter, packet loss, feedback, and timeliness. RTSP typically uses Real-Time Transport Protocol (RTP) as the actual data stream, and this is often referred to as the data-channel of RTSP. RealNetworks' RealPlayer uses a proprietary Real Data Transport protocol. RTP has a sister protocol; the Real-Time Transport Control Protocol (RTCP) that collects and communicates the Quality of Service (QoS) information, such as bytes sent, packets sent, lost packets, jitter, feedback, and round-trip delay, for the data being transported by the RTP. Applications can use the information from the RTCP to improve quality by slowing down the data flow, using smaller packet sizes, or using a lower compression of the data.