Centralized session/call control and distributed switching of payload is inherent in softswitch network design, also known as layered architecture.
The Softswitch provides call/session and media gateway control having the intelligence needed to properly execute the required service, including the service logic, authorization and billing. To perform this function a Softswitch utilizes standardized network signaling protocols such as SIP, SIP-T/I, H.323, H.248, BICC, and SIGTRAN.
