2. Core Design Principles of SS7

Signaling System No.7 (SS7) was designed as a common-channel signaling system that operates independently from bearer (voice or data) circuits. Unlike in-band signaling methods, where control information shares the same channel as user traffic, SS7 transports signaling messages over a dedicated signaling network.

All SS7 messages are carried over signaling links, historically implemented as 64 kbps DS0 channels on E1/T1 systems, and logically separate from bearer paths. As a result: