W3C's Web Services Architecture Working Group has published an initial Working Draft specification for Web Services Architecture Usage Scenarios. The document supplies a collection of some forty (40) usage scenarios and use cases "which illustrate the use of Web services, and which are used to generate requirements for the Web services architecture, as well as to evaluate existing technologies." The section on Use Cases provides additional context for some of the individual usages scenarios listed in the Usage Scenarios section (Travel agent use case; EDI-like purchasing). The Web services usage scenarios and use cases are categorized under the following labels: (1) Message exchange patterns, i.e., RPC, asynchrony, security, reliability, conversations; (2) Event based message exchange patterns; (3) System and other messages; (4) Service description above and beyond those outlined in '(1) - (3)'; (5) Discovery. Part of the document content was adapted from the XML Protocol Usage Scenarios document edited by John Ibbotson of IBM. The W3C Web Services Architecture Working Group has been chartered to draft a coherent architecture for a modular set of web services technologies by producing architectural documents and advising W3C regarding work in the Web services area.

Bibliographic information: Web Services Architecture Usage Scenarios. W3C Working Draft 30-July-2002. Edited by Hugo Haas (W3C) and David Orchard (BEA Systems). Version URL: http://www.w3.org/TR/2002/WD-ws-arch-scenarios-20020730/. Latest version URL: http://www.w3.org/TR/ws-arch-scenarios/.

Example Web services Usage Scenarios described:

• Fire-and-forget to single receiver
• Fire-and-forget to multiple receivers
• Request/Response
• Remote Procedure Call (RPC)
• Multiple Faults
• Multiple asynchronous responses
• Scenario Definition
• Description
• Request with acknowledgement
• Third party intermediary
• Communication via multiple intermediaries
• Caching
• Routing
• Tracking
• Caching with expiration
• Conversational message exchange
• Request with encrypted payload
• Message header and payload encryption
• Attachment encryption
• Authentication
• Message Integrity
• Authentication of data
• Asynchronous messaging
• Asynch/Synchronous specificity
• Transaction
• Sending non-XML data
• Incremental parsing/processing of SOAP messages
• Streaming Response
• Event notification
• Event Management Model
• System Messages
• Service Metadata
• Service Level attributes
• Operation Level attributes
• Namespaces with data and interfaces
• Versioning
• Classification system for operations
• Quality of service
• Address based Discovery
• Registry based discovery