Which protocol is used to describe the connection points of Web services?

Which protocol is used to describe the connection points of Web services?

• A. REST
• B. SOAP
• C. WSDL
• D. UDDI

Answer: (C)

Describing how to connect to a web service is defined by a contract that lists endpoints, operations, and data formats. WSDL is an XML-based description language that specifies the service’s interface: the available operations, the messages they exchange, the data types used, and where the service can be accessed (the endpoint URL) as well as how those operations are bound to a transport (for example, SOAP). This combination precisely captures the connection points a client must know to interact with the service, making it the best fit for describing how to connect. REST focuses on resources and their representations, without a formal contract for the exact operations and endpoints. SOAP defines the messaging protocol and envelope structure, but it relies on WSDL to describe the service interface and how to reach it. UDDI is a directory for discovering services, not a description of how to connect to them.

Describing how to connect to a web service is defined by a contract that lists endpoints, operations, and data formats. WSDL is an XML-based description language that specifies the service’s interface: the available operations, the messages they exchange, the data types used, and where the service can be accessed (the endpoint URL) as well as how those operations are bound to a transport (for example, SOAP). This combination precisely captures the connection points a client must know to interact with the service, making it the best fit for describing how to connect.

REST focuses on resources and their representations, without a formal contract for the exact operations and endpoints. SOAP defines the messaging protocol and envelope structure, but it relies on WSDL to describe the service interface and how to reach it. UDDI is a directory for discovering services, not a description of how to connect to them.