- From: Paul Denning <pauld@mitre.org>
- Date: Thu, 28 Mar 2002 16:36:01 -0500
- To: www-ws-arch@w3.org
This email kicks off discussion of D-AG0012, which now states - identify or create the use cases that validate the requirements and the web services architecture and illustrate the benefits of web services. Proposal: - identify or create a set of usage scenarios that are drawn from a broad set of W3C members and relevant liaison organizations, and can be mapped to WS Architecture requirements. Discussion I suggest we use the term "usage scenario" rather than use case. XMLP WG had a discussion of this distinction when it was doing the same thing for its requirements document. Basically, use cases (e.g., UML) are something more structured and oriented to software design. Usage scenarios are less structured, and perhaps more abstract to illustrate broad architectural concepts. The goal for the WSAWG and the architecture document should be to address a broad set of applications reflecting the diversity of the W3C membership as well as the organizations that we have identified as important liaisons (OMG, OASIS, etc.) There should be a mapping between usage scenarios and requirements for the web service architecture document. I'm not sure we want a usage scenario to actually be the requirement. I think there is a difference between a requirement and a usage scenario. The benefit of web services should be obvious from the usage scenarios. The architecture document introduction will probably talk about the benefits of web services. I would rather keep the usage scenarios short and not add the text that would be needed to explicitly state the benefits of each scenario. In what way does a usage scenario validate a requirement? The form of a requirement will be "The web services architecture shall ..." For example, "... shall define a way to describe web services". A related usage scenario might be "a web service provider publishes a description of its web service, and a web service user reads the description to determine how to invoke the web service." This requirement is derived from the usage scenario, so in a sense the requirement is valid because it relates to a usage scenario. If a requirement cannot be traced back to a usage scenario, then we can consider it invalid (or perhaps we would need to figure out a usage scenario for it). So, it would be a requirement of the requirement document to include a matrix showing the traceability between requirements and usage scenarios. We would then need to have traceability between the architecture document and each requirement in the requirements document. I am not familiar enough with the CSFA method to know how it views usage scenarios versus requirements. Requirements (to be determine) Several efforts related to web services have worked on usage scenarios: XMLP WG http://www.w3.org/TR/xmlp-scenarios/ WSDWG http://lists.w3.org/Archives/Public/www-ws-desc/2002Feb/0097.html http://lists.w3.org/Archives/Public/www-ws-desc/2002Feb/0115.html http://lists.w3.org/Archives/Public/www-ws-desc/2002Feb/0123.html http://lists.w3.org/Archives/Public/www-ws-desc/2002Mar/0090.html OASIS WSIA https://www.oasis-open.org/committees/wsia/scenarios/index.shtml http://lists.oasis-open.org/archives/wsia/200203/msg00046.html OASIS SSTC http://www.oasis-open.org/committees/security/docs/draft-sstc-saml-reqs-01.pdf OASIS XACML http://lists.oasis-open.org/archives/xacml/200112/msg00038.html http://lists.oasis-open.org/archives/xacml/200112/msg00045.html http://lists.oasis-open.org/archives/xacml/200203/msg00024.html http://lists.oasis-open.org/archives/xacml/200202/msg00061.html Others? Critical Success Factors (CSF) (to be determined) Paul
Received on Thursday, 28 March 2002 17:55:14 UTC