A programmable network switch that can process the signaling for all types of packet protocols. Also known as a "media gateway controller," "call agent" or "call server," such devices are used by carriers that support converged communications services by integrating SS7 telephone signaling with packet networks. Using network processors at its core, softswitches can support IP, DSL, ATM and frame relay in the same unit.

It Should Be Able To...
According to the International Softswitch Consortium, a softswitch should be able to (1) control connection services for a media gateway and/or native IP endpoints, (2) select processes that can be applied to a call, (3) provide routing for a call within the network based on signaling and customer database information, (4) transfer control of the call to another network element, and (5) interface to and support management functions such as provisioning, fault, billing, etc.

Software Makes It Flexible
The switching technology in a softswitch is in software (hence its name) rather than in the hardware as with traditional switching center technology. This software programmability allows it to support existing and future IP telephony protocols (H.323, SIP, MEGACO, etc.). See IP telephony. See also Soft-Switch.