Softswitch (Software Switch) is a next-generation network (NGN) operator used to route Voice over Internet Protocol (VoIP) calls to the intended recipient.

It generally runs on industry-standard hardware and serves the purpose of virtually connecting phone calls between two parties over the internet in IP network infrastructure.

In short, Softswitches are deployed in the networks of long-distance service providers and direct the IP packets by complying with NG (next generation) standards to reach the destination.

Softswitches are used for call control, routing, signalling, and terminating sessions in VoIP networks.

To understand the function of Softswitch, it majorly combines 3 elements signalling gateway, media gateway, and media gateway controller to serve different purposes.

Signalling Gateway:

It is a translation device used to pass information between IP-based networks such as SIP (Session initiation Protocols) and legacy SS7 (Signalling System 7) to be employed in PSTN (Public Switched Telephone Network).

Media Gateway:

It terminates the aging TDM circuits and packetizes media streams to transport to IP network using RTP (Real-time transport) protocols.

Media Gateway Controller or Call Agent:

It processes media streams and performs functions like playing recorded messages, call forwarding and call waiting.

The concept of Softswitch is applied to next generation networks or traditional networks.

The VoIP software switches made the users to connect virtually by performing the function of searching for intended recipient in the address book and transfer the call over PSTN.