1 Mapping the DAIS Concepts Simon Laws (IBM) Sastry Malladi (ORACLE) Savas Parastatidis (Univ. of Newcastle)

2 Background Educate DAIS WG about web services infrastructure WS-I, WS-Context, WSRF Do we have to make a choice of approach? Implicit vs explicit data resource addressing Service vs resource OGSA have chosen WSRF and the implicit approach Currently it seems that the answer is yes The service consumer must take different actions depending on whether an implicit or explicit approach is chosen However approaches can be mixed and matched

3 Approach How do we access data resources through various web services based infrastructure? Scenarios Stateful interactions with data resources Sessions with data services Discovery of data resources Access to metadata about data resources and/or services Third-party delivery Infrastructures Web Services-Interoperability (WS-I) only specifications WS-I plus WS-Context WS-I plus WS-RF

4 Scenario 1 Stateful interactions with data resources Using WS-I only

5 Scenario 1 - Using WS-I

6

7

8 Scenario 1 Stateful interactions with data resources Using WS-Context

9 Scenario 1 - Using WS-Context

10 Scenario 1 - Using WS-Context

11 Scenario 1 - Using WS-Context

12 Scenario 1 - Using WS-Context

13 Scenario 1 Stateful interactions with data resources Using WS-RF

14 Scenario 1 - Using WS-RF

15 Scenario 1 - Using WS-RF

16 Observations

17 DAIS and Naming DAIS is specifically about accessing data resources We need to be able to give names to those data resources OGSA V1 describes a three level naming scheme Human Readable Names Abstract Names Address The differences between the approaches lies in the abstract name to address mapping

18 WS-I -Focus on services -Registy lookup can result in many service URLs - A service can act on many resources -One or more resources can be specified in the message body at service call time - Abstract names can be passed to any service than understands them

19 WS-I + WS-Context -Focus on services -Context supports a sequence of messages across many services -Registy lookup can result in many service URLs - A service can act on many resources -One or more resources can be associated with a context

20 WS-RF -Focus on resources -Registy lookup can result in many EPRs - An EPR identifies one or more resources in the context of a service

21 Do We Have To Make A Choice? Mitigating the differences Optional discriminators in the message body WSDL binding operation parts WSRF TC in OASIS is considering embodiments of the Implied Resource Pattern WS-Addressing EPR Singleton pattern Context based approaches Living with the differences Mix and match Ultimately the consumer of the service has to make a choice To put a resource discriminator in the message body or not

22 General Issues Stability of supporting infrastructure Interoperability and adoption Composability Tooling Conceptual model

23 Questions ?