SCCP
Signalling Connection and Control Part
Although MTP3 (Message Transfer Part 3) provides routing capabilities in the guise of Point Codes, there is an inherent limitation when two SS7 networks need to exchange SS7 messages since point codes can overlap. SCCP overcomes this problem by adding a higher level of addressing in the form of unique Global Titles. Consequently, using SCCP in the protocol stack permits the routing of higher layer SS7 messages on a global basis. In addition, SCCP can operate in a connection orientated or connectionless state, with reliable delivery of messages if required.