RTP packet: a packet with an RTP header on the start, that is, RTP packet. Generally, in the bottom layer protocol, a packet contains only one RTP packet, but through some special encapsulation methods, the bottom layer packet can also contain more than one RTP packet. RTP payload: In RTP packet, the real information to be sent is RTP payload. For example, in an image conference, the image data is RTP payload. RTCP packet: the starting part is the RTCP header, which then controls the packet of the data, that is, the RTCP packet. Generally, many RTCP packages are merged and added with the header of the Upper-end signature. The length of the RTCP packet after the combination is determined by the length reserved in the RTCP header. Port: When RTP wants to send RTP packet and RTCP packet to the same IP Address, the port can be used to differentiate the destination. Transport address: Generally, IP Address and UDP port are used. Packet logs from a source transport address to a destination transport address. RTP session: For each RTP user, RTP session is defined by a pair of destination transport addresses (one for RTP and the other for RTCP ). It should be noted that in a multi-media conference, it is best to deliver different media resources in different RTP sessions. Synchronization source (SSRC): SSRC is the recognition value selected by a login machine. It is intended to enable one or two cognominal credenant in a rtp session. However, the same user does not have to use the same SSRC in different RTP sessions. Contributing source (CSRC): Previously mentioned that mixer can mix RTP packages from different sources into the same RTP packet. At this time, RTP will modify the SSRC related to this packet in the RTP header, and these SSRC are called CSRC. End system: if an application can generate an internal content package to be sent in RTP packet, or it can retrieve the content in RTP packet, it can be called End system. Monitor: if an application can receive the RTCP packet sent by all the participating ipant in an RTP session, it can be called Monitor. Monitor can be built in the End system or directly connected to RTP session. This Monitor is called the Third Party Monitor.
