All communication with a Windows Communication Foundation (WCF) service occurs through the endpoints of the service. Endpoints provide clients access to the functionality offered by a WCF service.

Each endpoint consists of four properties:

• An address that indicates where the endpoint can be found.
  
  
• A binding that specifies how a client can communicate with the endpoint.
  
  
• A contract that identifies the operations available.
  
  
• A set of behaviors that specify local implementation details of the endpoin

A WCF Service is comprised of the following major components. The diagram below shows how the components are related to each other:

• Service Contract
• Operation Contract
• Data Contract
• Data Member

Service Contract

Service contract is a contract that specifies the direction and type of the messages in a conversation. It is an interface or a class that defines the service contract in a Windows Communication Foundation (WCF) application. A service contract is the gateway to a service for external applications to make use of the service functions, and at least one service contract should be available in a service. A service contract is defined as follows:

// Student ServiceContract 
[ServiceContract] 
public interface IStudentService
 {
 // Define the OperationContact here…. 
}

The ServiceContract attribute of the interface defines the service contract in the service interface. The service contract defines the operations available in the service, operations like web service methods in a web service. IstudentService is a student service interface which exposes all the operation contracts or methods in this service to external systems.

Operation Contract

An operation contract defines the methods of the service that are accessible by external systems. The OperationContract attribute needs to be applied for all these methods, these are also like web methods in a web service. Operation contracts are defined as follows:

// Student ServiceContract 
[ServiceContract] 
public interface IStudentService 
{
 // Define the GetStudentFullName OperationContact here…. 
[OperationContract] 
String GetStudentFullName (int studentId); 
// Define the GetStudentInfo OperationContact here…. 
[OperationContract] 
StudentInformation GetStudentInfo (int studentId); }

Data Contract

A data contract defines a type with a set of data members or fields that will be used as the composite type in a service contract. It is a loosely-coupled model that is defined outside the implementation of the service and accessible by services in other platforms. To define a data contract, apply the DataContract attribute to the class to serialize the class by a serializer, and apply the DataMember attribute to the fields in the class that must be serialized. A StudentInformation data contract can be defined as follows:

[DataContract] 
public class StudentInformation 
{
 // Define the Datamembers here…. 
}

Data Member

A data member specifies the type which is part of a data contract used as a composite type member of the contract. To define a data member, apply the DataMember attribute to the fields that must be serialized. The DataMember attribute can be applied to private properties, but they will be serialized and deserialized, and will be accessible to the user or process. The code below shows how to define a data member in a data contract:

[DataContract] public class StudentInformation { _studentId = studId; [DataMember] public int StudentId { get { return _studentId; } set { _studentId = value; } } }


Hope you get this examples

• Transport -Defines the base protocol to be used like HTTP, Named Pipes, TCP, and MSMQ are some type of protocols.
• Encoding (Optional) - Three types of encoding are available-Text, Binary, or Message Transmission Optimization Mechanism (MTOM). MTOM is an interoperable message format that allows the effective transmission of attachments or large messages (greater than 64K).
• Protocol(Optional) - Defines information to be used in the binding such as Security, transaction or reliable messaging capability

The following table gives some list of protocols supported by WCF binding.

Below figure illustrate the functions of Endpoint

<system.serviceModel>
<services>
    <service name="MathService"
      behaviorConfiguration="MathServiceBehavior">
     <endpoint
     address="http://localhost:8090/MyService/MathService.svc" contract="IMathService"
      binding="wsHttpBinding"/> 
    </service>
    </services>
    <behaviors>
    <serviceBehaviors>
      <behavior name="MathServiceBehavior">
      <serviceMetadata httpGetEnabled="True"/>
      <serviceDebug includeExceptionDetailInFaults="true" />
      </behavior>
    </serviceBehaviors>
    </behaviors>
  </system.serviceModel>



Personally speaking once go through this tutorial it helps me a lot..
definately it will also helps you to better understand it

http://wcftutorial.net/EndPoint.aspx
http://www.codeproject.com/KB/WCF/WCFServiceSample.aspx  
http://www.codeproject.com/KB/WCF/WCFOverview.aspx 

Hello,

End Points

The metadata (wsdl) from <serviceMetadata httpGetEnabled> always lives at the base address, and so that's always where you can point svcutil/Add Service Reference.

The <endpoint address> is where the application endpoint lives.  So when you create the client and it talks to the service using the ITestService contract, it does so at that address.

Put another way, the base address is the address of the 'get wsdl' metadata endpoint, and the endpoint address is the address of the application endpoint (with your service's [OperationContract] operations).

<system.serviceModel>

 <bindings />

 <behaviors>

  <serviceBehaviors>

   <behavior name="DefaultBehavior">

    <serviceMetadata httpGetEnabled="true" />

   </behavior>

  </serviceBehaviors>

</behaviors>

 <services>

  <service behaviorConfiguration="DefaultBehavior" name="Test.TestService">

   <clear />

   <host>

    <baseAddresses>

   <add baseAddress=http://localhost:8081/Test/ />

    </baseAddresses>

   </host>

   <endpoint address=http://localhost:8082/Test/

   binding="basicHttpBinding" bindingConfiguration="" name="Web"

   contract="Test.ITestService" />

  </service>

 </services>

</system.serviceModel>

The service host is created the following way:

ServiceHost host = new ServiceHost(typeof(TestService));

host.Open();

Hope this is helpful !

Thanks