Network 320 Week 5

Real-Time Transport Protocol

Real-Time Transport Protocol (RTP) is a way for programs to manage the real-time multimedia, such as, audio and video, data over unicast (point to point) and/or multicast (multipoint) network services. RTP is used extensively in systems that involve streaming. VoIP, video teleconference applications and several television services utilize RTP.

RTP provides an IP-based transmission service for real-time communication between computers or devices. In combination with other protocols, RTP is used for transmitting audio and video information. VoIP uses a combination of protocols to transmit the phone data between computers or from a computer to a cell phone or land-line. VoIP data is changed from an analog signal to a digital signal. Layered protocols transfer, receive and interpret the signal; RTP is a part of the transport layer. RTP itself does not provide a mechanism to secure the transmission quality. It is however, able to ensure real-time communication even without such mechanisms. It uses consecutive numbering of the sent data packets. Based on this numbering the recipient can rearrange information that arrived in the wrong order. Numbering also serves as a way to determine the correct position of a data fragment within a data stream. This is particularly important for audio and video transmissions, from which information is continuously lost due to poor transmission quality. RTP works in conjunction with the User Datagram Protocol (UDP) to transfer the messages. The UDP protocol data is delivered faster, but loses reliability of delivery. In most instances, a dropped frame should not affect playback too badly. Playback is only affected if the network is severely congested causing slow delivery. It is possible to use RTP over the Transmission Control Protocol (TCP) since it is reliable but it often has problems with delivering data in a timely fashion. RTP and its companion RTCP (Real time Transport Control Protocol)...