The Global Title Translation (GTT) feature is designed for the signaling connection control part (SCCP) of the SS7 protocol
The GTT feature uses global title address (GTA) information to determine the destination of the MSU. The translation type (TT) indicates which global title translation table is used to determine the routing to a particular service database. Each global title translation table includes the point code (pc) of the node containing the service database, the subsystem number (ssn) identifying the service database on that node, and a routing indicator (ri). The routing indicator determines if further global title translations are required. GTA and TT are contained in the called party address (CDPA) field of the MSU.
The global title translation feature changes the destination point code and the origination point code in the routing label. The global title information is not altered.
Depending on how the global title translation data is configured, the routing indicator, the subsystem number, or the translation type in the called party address may also be changed by the global title translation feature. The gray shaded areas in Figure 1 show the message fields affected by global title translation.
