Real-Time Transport Protocol (RTP) and Real-Time Control Protocol (RTCP) are used in combination making it possible to monitor data delivery for large multicast networks. RTP carries the media streams, while RTCP is used to monitor transmission statistics and quality of service (see QoS). Monitoring allows the receiver to detect if there is any packet loss and to compensate for any delay jitter. Both protocols work independently of the underlying Transport layer and Network layer protocols. Information in the RTP header tells the receiver how to reconstruct the data and describes how the codec bit streams are packetized.