ASP.NET is actually a technology to produce client side controls and easily handle the controls from the serverside.
Server side runs separately that of client side. So once you produce the output from the client you are now dealing only with the htmls. You can produce object or embed tags to embed a control that is capable of invoking asynchronous streaming request to the server again from the browser. Those controls might be any silverlight or Flash applets which might call your server to get the actual stream.
There are lots of capabilities introduced with Silverlight lately which might allow you to show live streaming over network.
The tutorial might help :