How do you support WebSocket connections on the same port as your HTTP server in .NET? It turns out that this is not that hard, and you even have several choices to do so...
Option 1: TCP Proxy
You could use a TCP proxy port to divide traffic between the two targets. For example, all traffic would come in to port 80, but then HTTP traffic would be routed internally to 8001 and WS traffic to 8002. This is useful because it would allow you to use multiple technologies (in the example on their site, both NancyFX and Fleck) to host your web servers.
Option 2: SignalR
SignalR is great because of all the backwards compatibility that it supports for both the server and client. However, it is not the most lightweight framework. If you choose to use it, then it will absolutely support both HTTP and WS.
Option 3: Owin.WebSocket *My Favorite*
Owin supports WebSockets, and that is exactly what SignalR uses to host its WS connections. The awesome Mr. Bryce Godfrey extracted the Owin code from SignalR into a much smaller library called Owin.WebSocket.
The ONLY thing that I did not like about this implementation was that is uses inheritance to define endpoints, whereas I much prefer the ability to use delegates and lambdas. Because of this, I created Owin.WebSocket.Fleck, which allows you to use the Fleck API to map your WebSockets to an Owin context. A pull request is open to merge this into the main repository.