SuperSocket, an extensible socket application framework – Home
SuperSocket is a light weight, cross platform and extensible socket application framework. You can use it to build a server side socket application (like FTP server, SMTP/POP3/IMAP4 server, SIP server, etc) easily without thinking about how to use socket, how to maintain the socket connections and how socket works(synchronize/asynchronize).It is a pure C# project which is designed to be extended, so it is easy to be integrated to your existing system. If your systems (like forum/CRM/MIS/HRM/ERP) are developed in .NET language, you must be able to use SuperSocket to build your socket application as a part of your current system perfectly.
I know there are two famous NIO open source frameworks named “MINA" and “Netty" in Java World which are used widely by developers. If you want to look for a .NET portion of MINA or Netty, I suggest you try SuperSocket, although SuperSocket is not strong like MINA and Netty but it is very simple and you can use it easily.