RTP enables identification of the type of data being transmitted, and using sequence numbers, what order the packets should be presented in. Since correct packet order is not guaranteed in transmission, it is important for the receiver to be able to order packets and detect packet losses. Timestamping allows synchronization of media streams from different sources, and smooths out possible jitter and noise when real time applications place received packets into a playback buffer. RTP is paired with RTCP (Real Time Transport Control Protocol) which examines the quality of the connection and sends feedback to the sender and receiver, allowing both to negotiate the best transmission scheme. RTCP also provides control and identification mechanisms for RTP transmissions.