General Web Services FAQ

• What is a Web Service?
  

  In the simplest form, a Web Service is any piece of software that is available over the Internet and uses a standardized XML messaging system.

• How are Web Services different than typical Client Server applications?
  

  The simplest answer would be the addition of XML as messaging format. Because all communication is in XML, Web Services are not tied to any one operating system or programming language--Java can talk with Perl; Windows applications can talk with Unix applications.

• Web services take only strictly-formatted requests from applications and return strictly-formatted responses using XML.
  
  
• What is the Web Service protocol stack?
  

  The Web Service Protocol stack consists of four layers:

  • Service Transport: This layer is responsible for transporting messages between applications. Currently, this includes HTTP, SMTP, FTP, and newer protocols, such as Blocks Extensible Exchange Protocol (BEEP).
  • XML Messaging: This layer is responsible for encoding messages in a common XML format so that messages can be understood at either end.
  • Service Description: This layer is responsible for describing the public interface to a specific Web service. Currently, service description is handled via the WSDL.
  • Service Discovery: This layer is responsible for centralizing services into a common registry, and providing easy publish/find functionality. Currently, service discovery is handled via the UDDI.

• Where do I find specifications for most things SOAP?

Try the W3C site

• What is SOA?
  

  SOA is made up of loosely coupled services, described by platform-agnostic interfaces, and that can be discovered and invoked dynamically.