TCAP
Transaction Capabilities Application Part
TCAP is an SS7 protocol which is designed to facilitate the establishment of dialogues between SS7 nodes in the network. These dialogues allow physical nodes running separate subsystems to communicate directly with one another, providing a multiplexing/demultiplexing service akin to UDP, TCP etc. For example, a single node may be running MAP (Mobile Application Part) and CAP (CAMEL Application Part) as separate subsystems. Two separate TCAP dialogues can be established to the same physical node, with the traffic for each subsystem separated by the appropriate dialogue.