ISUP, or ISDN User Part, is a signaling protocol used in telecommunication networks for setting up and maintaining telephone calls. It is the most widely-used protocol for voice call setup on Public Switched Telephone Networks (PSTNs) and Integrated Services Digital Network (ISDN). ISUP defines how two endpoints of a phone call communicate with each other to establish, maintain and terminate a connection between them.
The main purpose of ISUP is to provide efficient control signals over an existing digital network infrastructure such as PSTN or ISDN. This ensures that all users connected to the same network can share resources efficiently while having reliable communication links between them. The primary function of this protocol is establishing connections by sending messages from one endpoint to another through various stages like address exchange, alerting phase etc., until both ends are ready for audio transmission. Additionally it also provides support services such as charging information exchange during the duration of the call which helps in accurate billing purposes once disconnected from each other’s endpoints at last stage i:e release procedure..
In short we can say that without using any additional hardware equipment’s, using just software based protocols like ISUP makes our life easier by providing us efficient way for communicating over long distances. It has made international calling much more affordable than ever before due its cost effective nature & advanced features which make sure smooth functioning throughout entire process till completion & disconnection respectively.
