Normally when we going to host WCF service in IIS or WAS need to have svc file. The Service.svc file is an XML-based file that must include an @ServiceHost directive. The directive identifies your
service, and it should include attributes that identify the service code language and the name
of the service.
But think a scenario where you have lots of services in a enterprise environment.Then you have to maintain lot of svc files.Its adds extra penalty to the developer as well as the deployment engineer.fortunately WCF 4.0 has shipped with new future called Configuration based activation which is capable for overcome this problem.
There are lo of WCF 4.0 features.Please refer MSDN . http://msdn.microsoft.com/en-us/library/dd456789(v=vs.100).aspx
When using CBA we don’t need to use and svc file instead of that Configuration-based activation takes the metadata that used to be placed in the .svc file and places it in the Web.config file.It use <serviceHostingEnvironment>/<serviceActivations> tags.
let see below example.we need to add below code to the web.config file.
After deploy to the IIS(with out svc).
For additional information please refer : http://msdn.microsoft.com/en-us/library/ee358764(v=VS.110).aspx