SIP is a part of the VOIP family, which is a signaling protocol used to create, manage, and terminate VOIP sessions in a networking environment. Examples of SIP include a two-way phone call or a conference call, or multimedia sessions with multiple hosts. After the initiation of the session, the data is transferred through the Real time Transport Protocol (RTP) over the dedicated channel. Basically, the family of RTPs governs the transport and the flow control of all multimedia items (RTCP controls the flow).
Wireshark can assemble a stream of RTP packets in order to play back the conversation that happened between two parties (use it ethically!).
SIP runs over UDP and ...
