Gateway Service

Gateway is a design pattern, which enables authentication, routing, monitoring, A/B and other infrastructural capabilities that you can add to your web site in a service injection manner. 

By service injection, you don’t need to change your code much, as there is no direct dependency between the Gateway and your web site. You just use the Gateway as a service.

Gateay Live testing sites:
https://dangateway.cloudapp.net  
(username/password):  user1@danyang.onmicrosoft.com/test@123 , user2/test@123
User1 will be routed to East, User2 to West

Gateway Source Code:  http://sdrv.ms/12RSZjM