Routing in ASP.NET MVC

Enables you to map URLs that does not map to any specific files in a web site. You should add default MVC routes to Application_Start event in Global.asax file as shown in the example below

check MSDN page ASP.NET routing for more information.

RouteCollection

Provides a collection of routes for ASP.NET routing. This class is derived from Collection<RouteBase>. 

You can define custom routes by using RouteBase class. See a tutorial.

Attribute routing

introduced in Web API 2 to overcome challenges faced with creating routes with conventional based routings. Uses attributes to define routes.

References

Google search - ASP.NET MVC Routing 

UrlRoutingHandler MSDN 

http://stackoverflow.com/questions/1192446/understanding-routing-in-global-asax-asp-net-mvc

http://msdn.microsoft.com/en-us/library/cc668201%28v=vs.100%29.aspx

http://www.asp.net/mvc/overview/controllers-and-routing