The Windows Communication Foundation (WCF) Architecture is divided into five different layers which are described as below:



Figure 1: WCF Architecture Diagram.

1. Application Layer
   
   It will describe how the application consumes the WCF service using with different below layers.
    
2. Contract Layer
   
   It is the Second Layer of WCF Architecture
   
   • Service Contract

   Describe the Interface Methods with Service Level Operations.
   

   • Data Contract
      
   Describe Data Classes and Method that will be exposed to the client.
   
   • Message Contract
      
   Describe the type of format need to be deployed to make communication between client and service.
   
   • Policies and Binding
      
   Condition and privileges required to communicate with service.
    
3. Service Runtime Layer
   
   This is the third layer of WCF architecture. It mainly deals with different types of behaviors that occurs service runtime.
   
   • Error Behavior: Specifies what internal errors occur on service.
   • Dispatch Behavior: Deals with how message will be processed.
   • Throttling Behavior: Deals how many processes should be completed.
   • Metadata Behavior: Conveying metadata information.
   • Instance Behavior: How many instances will be created is know during service running.
   • Transaction Behavior: Rollback happens if an error occurs in service.
     
4. Messaging Layer
   
   The Communication of message takes place with the help of channels where it is located in channel stack.
   
   Channel Stack has two different types of channels
   
   • Transport Channel: Deals with Sending and Receiving messages.
   • Protocol Channel: Deals with Security, integrity and effective processing.
      
5. Activation and Hosting Layer

This layer mainly deals with process of execution and deployment. The Service can be hosted on IIS, WAS, Self Hosting, Windows Services.

I hope this article is useful for you. I look forward for your comments and feedback..

Thanks Vijay Prativadi...