FreeSWITCH

What FreeSWITCH is and what it is not

FreeSWITCH is a scalable softswitch. In practical terms this means that it can do anything a traditional PBX can do and much more. It can (and does) act as the core switching software for commercial carriers. It can scale up to handle thousands of simultaneous calls. It can also scale down to act as a simple softphone for your laptop or personal computer. It can also work in a cluster of servers.

FreeSWITCH is not a proxy server. If you need proxy server functionality, then consider OpenSIPS, Kamailio, or other similar software. FreeSWITCH is a back-to-back user agent or B2BUA. In this regard, it is similar to Asterisk and other IP PBX software.