ASP.NET MVC and Web Forms registration

Question

How does IIS know when to route a requests to the ASP.NET MVC framework and the not the Web Forms framework?

Looking through the Web.config of an MVC project I can't see any modules or handlers that are registered, and nothing the Global.ascx seems to do it. So I am at a bit of a loss as to how the system decides which should be used to route a request.

Answer 1

After looking at the MapRoute method the system registers a set of Routes which offload a matching request to an IRouteHandler. The IRouteHandler then returns a IHttpHandler that actually handles the final request.

This is my understanding so far so it might not be 100% correct.