BYE packet
A BYE (or Goodbye) packet is a type of Real-Time Transport Control Protocol (RTCP) packet that is sent when a participant in a multicast event leaves the session. Along with the media data transmitted, RTCP packets are periodically sent to each participant in a multicast session. These contain information related to quality of service (QoS), information about the data source, and so on. When a source is no longer active, it sends a BYE packet, which reports that the source has left the session and, optionally, the reason for leaving.