What is RTCP?
The RTP control protocol (RTCP) is based on the periodic transmission of control packets to all participants in the session, using the same distribution mechanism as the data packets.
Functions of RTCP
- It provides feedback on the quality of the data distribution. Different types of packets are used. We will discuss those in the next page.
- It carries a persistent transport-level identifier for an RTP source called the canonical name or CNAME. SSRC may change from time to time but CNAME remains the same. It is used to identify a participant during the session. RTCP may also contain extra information for the participants like email.
- By having each participant send its control packets to all the others, each can independently observe the number of participants. This number is used to calculate the rate at which the packets are sent. More users in a session means an individual source may send packets less frequently.