Web Services Architecture Presentation for ECE8813 Spring 2003 By: Mohamed Mansour

What is a Web Service Any piece of software that makes itself available over the Internet and uses a standardized XML messaging system

Roles Service Provider Service Requestor Discovery Agencies

Wire Protocol Transport  HTTP (or other Internet protocols) Packaging  SOAP (or other packaging protocols) Extensions  Context, routing, policy

SOAP Example <SOAP:Envelope xmlns:SOAP=

End-to-End Scenario Requestor SOAP run-time SOAP message Network Layer HTTP Request Server (Provider) SOAP run-time Network Layer Deliver HTTP Dispatch to appropriate runtime

Description Stack Interface, Implementation  Described in a WSDL (Web Service Description Language) document  Minimum layers for any web service

Stack Components

WSDL Example

WSDL Example – contd.

WSDL Example – contd.

WSDL Example – contd.

Description Stack – contd. Policy  additional description to specify the business context, qualities of service, security requirements and offerings, and management requirements. Presentation  how to render the input and output messages on a screen for a user to interact with. This is particularly useful for rendering Web services to users on many different types of devices. Orchestration  An orchestration description reflects a simple choreography of Web service invocations between two business partners to complete a multi-step business interaction. Composition Service Level Agreements Business Level Agreements

Discovery Stack Publication  Providers produce their service descriptions in a UDDI document.  Direct publish (ftp, CD-ROM, …)  UDDI registry Discovery  Discovery methods parallel publication methods Inspection  Web Service Inspection Language (WSIL)  a de-centralized, light weight method

Resources