Originally created for circuit-switched telephony, the signaling protocol has faced a substantial change with the arrival of Long-Term Evolution networks. Because packet-switched architectures necessitate a new method to signaling, SIGTRAN, a collection of standards , was established to convey SS
SS7 , TAP and the Transition to the Fourth Generation
Historically, ISUP served as the main system for voice messaging, reliably handling calls across the public switched telephone network . As systems advanced, SIGTRAN emerged to link this legacy SS7 domain with packet-switched technologies, allowing communication to flow over improved data network