1. Overview of Web Services
ECE1770 Expert Topic Assignment
Overview of Web Services
Fan Chen
Alvin Mok

2. Outline
What are Web Services & How Web Services Emerge
Web Services Architecture&Operations
Web Services Core Protocols
Some Issues
Web Services and other Middleware Platforms
Introduction to Microsoft .NET

3. What are “Web Services”?
Web Services are evolving, middleware platform that facilitate program-to-program interactions.
A service is a software entity that can be discovered and invoked by other software systems.
Definition from standardization body W3C
A Web service is a software system identified by a URI, whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems.These systems may then interact with the Web service in a manner prescribed by its definition, using XML based messages conveyed by internet protocols

4. How “Web Services” Emerge
Web-based Applications Exploiting
E-Business Urging the program-to-program interactions and and integration across heterogeneous platforms
It came to the market at the time when demand for such technology was growing rapidly
The existing middleware technologies were not implemented with the Web in mind
It is backed by many key organizations (both commercial and non-commercial)

5. Web Services Standardization Bodies
W3C:World Wide Web Consortium
the most notable web organization founded in 1994 by the inventor of the web
Web Architecture, Document formats, interaction, etc
OASIS: Organization of Structured Information Standards
Drives the development, convergence and adoption of e-business standards
Service register and publish, Security, Transaction,etc
WS-I: Web Services Interoperation Organization
Initiated by IBM, Microsoft and other vendors
Articulate/promote a common Web Services vision
Integrate specifications from various standards bodies

6. Web Services Basic Architecture
Web services are consistent with established Service-Oriented Architecture(SOA) principles.
Web Services Component
Service
Service Description
Web services Roles
Service providers.
Service brokers
Service requestors.
Web Services Operations
Publish
Find
Interact

7. The Conceptual Web Service Stacks
Format: XML,Extensible Markup Language, to define structures of documents
Search and Find: UDDI
Universal Discovery Description and Integration, for registries of Web services
Description: WSDL
Web Services Description Language, to describe networked XML-based services
Messaging: SOAP
Simple Object Access Protocol, to define a uniform way of passing XML-encoded data.
Transport: Internet Protocol,HTTP, STMP, etc.

8. Operations and Message Flow

9. Some Issues Technology Areas to be Standardized
Security: Inter-enterprise communications secure (XKMS, XACML,etc)
Business Process Management (WSFL)
Quality of Service and Reliable Messaging
System&Network Management
Chaos: There are tons of proposals from vendors but none of them has been universally accepted.
Different implementation for core protocols: Commercial and open-source toolkits vary widely.
A long way to go before web services cover the full range of requirements for e-business!

10. No one-size-fits-all solution!
Web Services and Other Middleware Platforms -A Vision or Over-simplification?-
No one-size-fits-all solution!

11. Applicability-Examples
Web Interface
Web Services
Secure Architecture with Firewall
Legacy Component( other CORBA EJB)
CORBA
Mobile Environment/Thin Client
Performance

12. Web Services and CORBA -A Possible Integration Scenario-
SOAP request Generated
Gateway maps WSDL to IDL, builds COBRA request and send to the server
SOAP response is build out of the COBRA response

13. Web Services and Java Java community sees XML as complementary
Java for algorithms, communications
XML as a universal data interchange format
Java API for XML:JAXP, JAX-RPC, JAXM, JAXR
J2EE + Web Services Developer Pack
Only for interoperation outside Java world
JMS, RMI, RMI/IIOP between Java applications

14. -Thank You-