-> A route is a URL pattern that is mapped to a handler. The handler can be a physical file such as an .aspx file in a web forms application. A handler can also a class that processes the request such as a controller in an MVC application.
-> To define a route, you create an instance of the Route class by specifying the URL pattern, the handler and optionally a name for the route.
MapHttpRoute, MapPageRoute, MapRoute
-> MapHttpRoute maps to WebAPi
-> MapPageRoute maps to aspx
-> MapRoute maps to MVC
->MapRoute is a method of the class RouteCollectionExtenstions which is in System.Web.Mvcnamespace.
-> MapHttpRoute is a method of the class HttpRouteCollectionExtensions which is in Sytem.Web.Http namespace