SS7

SS7 History

During the first 50 years all signaling was accomplished in-band. In 1960 signaling went digital, a development that 20 years later set the stage for SS7 (Signaling System #7) a system used for signaling on telephone networks all over the world.

SS7 Signaling

Common Channel Signaling System No. 7 (SS7 or C7) is an international protocol and a worldwide standard for telecommunications.

SS7 defines the procedures and protocol by which network elements in the telephone network exchange information. Signaling is over a digital network for executing functions such as call setup, routing and control of wired and wireless calls.

The reason for developing SS7 was to separate call management and signaling functions from the voice channel. By adding functions for quering databases with customer related information SS7 has been instrumental in developing new services for networks. SS7 now supports distributed computer systems permitting access to intelligent database functions and other software driven services.

SS7 encompasses all aspects of control signaling for complex digital network, including the reliable routing and delivery of control messages foor establishing and monitor calls. SS7 is also designed to meet both present and future network requirements, such as:

• Management and maintenance
• Number portability
• Name/number display
• Freephone, toll, collect and credit calls.
• Call forwarding
• Three-way calling
• Wireless roaming
• Mobile subscriber authentication