SS7s

SS7s, short for Signaling System 7, is a telecommunications signaling system used to facilitate the exchange of information between network elements in a telephone network. It was introduced in the early 1980s as a replacement for the earlier Signaling System 6 (SS6). SS7 is primarily used for mobile telecommunications networks but is also employed in fixed-line networks.

The system operates by sending and receiving messages between network elements, such as mobile switching centers (MSCs), visited location registers (VLRs), and home location registers (HLRs). These messages are called "signaling" and can include information such as call SETUP and TEARDOWN, location and roaming information, and authentication and identity verification.

SS7 is a packet-based signaling system, meaning that the signaling messages are carried over a packet-switched network, such as the public switched telephone network (PSTN). This allows for greater flexibility and efficiency in signaling, as well as improved error detection and correction.

The use of SS7 has several benefits, including increased capacity, improved reliability, and advanced functionality such as support for mobile multimedia services and location-based services. However, the system is also considered to be vulnerable to certain security threats, such as eavesdropping and spoofing, which can compromise network security.

The widespread adoption of SS7 has led to the development of newer signaling systems, such as the International Mobile Telecommunications-Advanced (IMT-Advanced) and the Diameter Signaling protocol. Nevertheless, SS7 remains a widely used and supported signaling system in many parts of the world due to its maturity and cost-effectiveness.