Awesome

The SIPSorcery project is an experiment into the depths of the Session Initiation Protocol (http://www.ietf.org/rfc/rfc3261.txt). The project is a combination of the source code available here on GitHub (previously sourceforge & codeplex) and a live service hosted at http://www.sipsorcery.com/. The project has its roots in a previous project called mysipswitch (http://www.codeplex.com/Wikipage?ProjectName=mysipswitch) which was deprecated in the mid noughties.

At its heart the project consists of a C# SIP protocol stack that implements all the required UDP, TCP and TLS transports. In addition to the SIP stack a number of related protocols: STUN (http://tools.ietf.org/html/rfc3489], SDP (http://tools.ietf.org/html/rfc4566), RTP & RTCP (http://tools.ietf.org/html/rfc3550) are implemented to varying degrees.

The SIP Proxy and SIP Application Server make heavy use of the Microsoft Dynamic Language Runtime (http://dlr.codeplex.com/) with the IronRuby (http://ironruby.codeplex.com/) engine being heavily used in dialplan processing and the IronPython (http://ironpython.codeplex.com/) engine being used for the SIP Proxy control script.

There are 3 main areas the SIPSorcery project focuses on:

The core SIP protocol stack and associated plumbing code, contained in the sipsorcery-core source code directory. The SIP server applications are:

SIP Proxy with dispatching mechanism for application server fault tolerance,
SIP Registrar,
SIP Registration Agent, registers contact information with 3rd party SIP providers,
SIP Application Server, multi-user SIP call processing using Ruby dialplans,
SIP Notification Server, supports the presence and dialog SIP event package notifications,
SIP Monitoring Server, receives and collates log messages from the other servers that can then be viewed from a web page or SSH session,
WatchTower Server, monitors SIP Application Servers and updates the SIP Proxy dispatch file,
SSH Server, uses the [url:NSsh|http://nssh.codeplex.com/] project to provide a multi-user SSH session for server monitoring.
An end-user Silverlight client application for managing the sipsorcery.com service, contained in the sipsorcery-silverlight code directory,
The SIP protocol stack is able to run within Silverlight allowing SIP TCP communications directly from a browser.
A basic C# softphone example application.