An RTP session consists of a number of applications communicating with RTP, and is identified by a network address and two ports. One port is used for media data and the other for RTCP (real time transfer control protocol) control data.
Session participants can send, receive, or do both. Each media type is transmitted in a separate session, enabling participants to choose which media types they want to receive. For example, a user may just want the audio portion of a streaming music video.