Web Service Specifications

1^st Generation Specifications

The web-service framework by W3C consists of a foundation built on three core XML-based specifications: WSDL, SOAP, and UDDI. The standards, in conjunction with SO-Design Principles, form a basic XML-based web-service driven SOA.

The 1^st generation architecture allows for the creation of independent web-services. It has several limitations addressed in 2^nd generation specifications.

Simple Object Acccess Protocol: Establishes a standard message format that consists of an XML document capable of hosting RPC and document-centric data.

• SOAP v1.1: Maintained by W3C. Specification is available here.
• SOAP v1.2: Maintained by W3C. Specification is divided in four parts - Primer, Messaging, Adjuncts and Assertions and Test Collection

Web Service Description Language: Providing the foremost language for the description of Web service definitions.

• WSDL v1.1: Mantained by W3C. Specification available here
• WSDL v1.2: Maintained by W3C. Specification available in two parts - Core Language and Message Patterns.

2^nd Generation Specifications

The 2^nd generation specifications position SOA as a viable successor to the prior distributed-platforms.

Reliability and Messaging: Propose features that deal with reliabile delivery, self-governing messaging, message attachments, and message transmission performance.

• WS-ReliableMessaging: Available at MSDN and DeveloperWorks
• WS-Addressing: Available at MSDN
• MTOM, DIME: Available at MSDN
• MTOM and XOP: Available at W3C
• WS-Attachments: Available at DeveloperWorks

Policies and Metadata: The WS-Policy framework comprises of a set of specifications that allow for the description of policies like business-rules, security etc

• WS-Policy: Available at XML-SOAP.org, and a newer proposed version at W3C. Also available at DeveloperWorks
• WS-PolicyAssertions: Available at DeveloperWorks
• WS-MetadatExchange: Aavailable at MSDN

Security: The WS-Security framework provides a thorough security model consisting of a host of specifications

• WS-Security: Maintained by OASIS
• WS-SecureConversation, WS-Federation, WS-Trust: All maintained by OASIS
• XML Encryption, XML Signature, XKMS, XACML, SAML: Maintained by W3C
• WS-I Basic Security Profile: Maintained by WS-I

Context and Transaction Management: The WS-Coordination specification provides a context management system. Supports atomic and long-running transactions.

• WS-Coordination: Maintained by OASIS
• WS-Transaction: Maintained by OASIS
• WS-AtomicTransaction: Maintained by OASIS
• WS-BusinessActivity: Maintained by OASIS

Business Process Definitions: Provides support for workflow - orchestration and choreography.

• BPEL: Maintained by OASIS
• WSCI: Maintained by W3C
• BPML: Maintained by BPMI (Note that there are not many takers for BPML. BPEL has a wider acceptance.