The FreeSWITCH design - modular, scalable, and stable

The design goal of FreeSWITCH is to provide a modular, scalable system around a stable switching core, and to provide a robust interface for developers to add to and control the system. Various elements in FreeSWITCH are independent of each other and do not have much knowledge about how the other parts are working, other than what is provided in what are called "FreeSWITCH APIs". The functionality of FreeSWITCH can be extended with loadable modules, which tie a particular functionality or an external technology into the core.

FreeSWITCH has many different module types that surround the central core, like sensors and interfaces connect a robot brain to the external environment. The list includes the following:

The following diagram shows what the FreeSWITCH architecture looks like and how the modules orbit the core of FreeSWITCH:

By combining the functionalities of the various module interfaces, FreeSWITCH can be configured to connect IP phones, POTS lines, WebRTC, and IP-based telephone services. It can also translate audio formats and provides an Interactive Voice Response (IVR) system with custom menus. A FreeSWITCH server can also be controlled from another machine. Let's start by taking a closer look at a pair of important module types.