ABC are 3 things that WCFServices end point must have.
"A" stands for Address: Where is the service?
"B" stands for Binding: How do I talk to the service?
"C" stands for Contract: What can the service do for me
Address - Address specifies where is the service
Binding - Binding specifies how to communicate with service
Contract - Contract specifies what functionalities or operations are exposed by service
