Sample code from the MSDN library about socket programming in C# (asynchronously).

Asynchronous Server Socket Example
http://msdn.microsoft.com/en-us/library/fx6588te.aspx

Asynchronous Client Socket Example
http://msdn.microsoft.com/en-us/library/bew39x2a.aspx

Using an Asynchronous Server Socket
http://msdn.microsoft.com/en-us/library/5w7b7x5f.aspx



Reference for Network Programming in general in the .NET Framework 4.5:
http://msdn.microsoft.com/en-us/library/4as0wz7t(v=vs.110).aspx