RTCP is real time control protocol is based on the periodic transmission of control packets to all participants in the session.

Functions of RTCP

• It is used to identify participant during session.

• RTCP may also contains extra information for participants like in Email.

• It provides feedback on quality of data distribution.

Receiver report (RR): RR is used for informing the sender and other receivers about the quality of service. Provides quality feedback i.e. number of last packet received, number of lost packets timestamp.

Sender report (SR): All the active senders in conference send the sender report periodically in order to report transmission of packets. SR also contains the time at which the message is sent, which helps receiver to synchronize the messages in order.

Source description (SDES): Provides information about the source (e.g. email address, phone number, full name of participant)

Bye: A source sends a BYE message to shut down a stream. It allows an endpoint to announce that it is leaving the conference.

Application specific function: It is a packet for an application that wants to use new applications which are not defined in the standard. Provides for future extensions of new features for multimedia application. It is now intended for experimental use as new applications and new features are developed.