The Real-Time Transport Control Protocol
) is a sister protocol of the Real-time Transport Protocol
(RTP). Its basic functionality and packet structure is defined in the RTP specification RFC 3550,RFC 3550, RTP: A Transport Protocol for Real-Time Applications
, H. Schulzrinne, S. Casner, R. Frederick, V. Jacobson, The Internet Society (July 2003) superseding its original standardization in 1996 (RFC 1889).
RTCP provides out-of-band statistics and control information for an RTP flow. It partners RTP in the delivery and packaging of multimedia data, but does not transport any media streams itself. Typically RTP will be sent on an even-numbered UDP
port, with RTCP messages being sent over the next highest odd-numbered port.RFC 3605, Real Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP)
, C. Huitema, Microsoft (October 2003) The primary function of RTCP is to provide feedback on the quality of service
(QoS) in media distribution by periodically sending statistics information to participants in a streaming multimedia session.
RTCP gathers statistics for a media connection and information such as transmitted octet
and packet counts, lost packet counts, jitter
, and round-trip delay time
. An application may use this information to control quality of service parameters, perhaps by limiting flow, or using a different codec
RTCP itself does not provide any flow encryption or authentication methods. Such... Read More