An Abstract WSDL contains only Messages, PortTypes, and Operations
Abstract WSDL consists of the structure of the message that is like what operation, what is the input, what is the ouput and what is the fault message used by each operation to communicate with the web service, and their format.
An abstract WSDL document describes what the web service does, but not how it does it or how to contact it. An abstract WSDL document defines: the operations provided by the web service.
Concrete WSDL has all the things that the abstract wsdl has in addition it has transport(http,jms) details to tell how the web service communicates and where you can reach it. A concrete WSDL document contains the abstract WSDL definitions, and also defines: the communication protocols and data encodings used by the web service, the port address that must be used to contact the web service. SOAP clients must retrieve the concrete WSDL file before sending a SOAP request to the service.
Abstract WSDL:- Used on server side,contains request,response and type of operation performed.
Concrete WSDL:- Used on client side,contains abstract wsdl and transport used.