Service_Switching_Point
In telephony, a service switching point (SSP) is the telephone exchange that initially responds, when a telephone caller dials a number, by sending a query to a central database called a service control point (SCP) so that the call can be handled. The service switching point uses the Signalling System No. 7 (SS7) protocols which are responsible for the call setup, management, and termination with other service switching points.