Web Services Platform Elements

Web Services have three basic platform elements: SOAP, WSDL and UDDI.

What is SOAP?
SOAP is a simple XML-based protocol to let applications exchange information over HTTP.
In simple: SOAP is a protocol for accessing a Web Service.

• SOAP stands for Simple Object Access Protocol
• SOAP is a communication protocol
• SOAP is a format for sending messages
• SOAP is designed to communicate via Internet
• SOAP is platform independent
• SOAP is language independent
• SOAP is based on XML
• SOAP is simple and extensible
• SOAP allows you to get around firewalls
• SOAP is a W3C standard

What is WSDL?
WSDL is an XML-based language for describing Web services and how to access them.

• WSDL stands for Web Services Description Language
• WSDL is based on XML
• WSDL is used to describe Web services
• WSDL is also used to locate Web services
• WSDL is a W3C standard

What is UDDI?
UDDI is a directory service where businesses can register and search for Web services.

• UDDI stands for Universal Description, Discovery and Integration
• UDDI is a directory for storing information about web services
• UDDI is a directory of web service interfaces described by WSDL
• UDDI communicates via SOAP
• UDDI is built into the Microsoft .NET platform

What is Service-oriented architecture?

Web services can also be used to implement an architecture according to Service-oriented architecture (SOA) concepts, where the basic unit of communication is a message, rather than an operation. This is often referred to as "message-oriented" services.

SOA Web services are supported by most major software vendors and industry analysts. Unlike RPC Web services, loose coupling is more likely, because the focus is on the "contract" that WSDL provides, rather than the underlying implementation details.