Web service is a part of WCF. WCF offers much more flexibility and portability to develop a service when comparing to web service. Still we are having more advantages over Web service, following table provides detailed difference between them.
|Hosting||It can be hosted in IIS||It can be hosted in IIS, windows activation service, Self-hosting, Windows service|
|Programming||[WebService] attribute has to be added to the class||[ServiceContraact] attribute has to be added to the class|
|Model||[WebMethod] attribute represents the method exposed to client||[OperationContract] attribute represents the method exposed to client|
|Operation||One-way, Request- Response are the different operations supported in web service||One-Way, Request-Response, Duplex are different type of operations supported in WCF|
|XML||System.Xml.serialization name space is used for serialization||System.Runtime.Serialization namespace is used for serialization|
|Encoding||XML 1.0, MTOM(Message Transmission Optimization Mechanism), DIME, Custom||XML 1.0, MTOM, Binary, Custom|
|Transports||Can be accessed through HTTP, TCP, Custom||Can be accessed through HTTP, TCP, Named pipes, MSMQ,P2P, Custom|
|Protocols||Security||Security, Reliable messaging, Transactions|
Hope this will help you!