Introduction to Web Services

Web services are self-describing business functions that are accessible from any Web-connected device using a set of messaging protocols, programming standards, and network registration and discovery facilities.

A Web service is a discrete piece of business functionality that:

Exposes and describes its functionality and attributes in WSDL
Allows other services to locate it on the Web using UDDI registries
Allows remote services to invoke it using standard Internet protocols
Returns a response to the requesting application over the same protocol

Web Services components: WSDL and UDDI