Web Services Definition

Software systems that support interoperable network interactions

• Web service interface described in WSDL (Web Services Description Language)
• Other systems interact with Web services using SOAP (Simple Object Access Protocol) messages
• Data is exchanged using XML format
• Messages are sent using HTTP, SMTP

WSDL - Platform and Language independent XML description of Web service
UDDI - Universal Description, Discovery, and Integration - Registry of organizations and their Web services

What is SOA - Service Oriented Architecture

SOA is a set of distributed software components that publish service descriptions and interact using messages.

There are usually 3 participants

1. Service Provider - Creates service and description and publish in registry
2. Service Requester - Finds service description and service and uses the service
3. Service Registry - Publishes services and allows service requester to search registry

Old SOA Implementations

DCOM - Distributed Component Object Model
CORBA - Common Object Request Broker Architecture
EDI - Electronic Data Interchange

Drawbacks

• DCOM - Microsoft specific; no service registry
• CORBA - complex software; expensive to install and maintain
• EDI - no service registry; no standard for service descriptions

New SOA Implementation

Web Services

Advantages

• Common language for writing service descriptions
• Platform/language independent messaging protocol