Web Services - Resource Framework (WS-RF) is a new (published ~ 2004-01-20) collection of proposed standards that redefine how to make a grid service out of a web service. The sponsors of the new standards are the Globus Alliance, IBM and HP. Microsoft are neutral on this issue at present. I'm not sure what BEA's position is.

WS-RF [i]replaces[/i] the OGSI 1.0 standard of GGF. If WS-RF is accepted by the grid community (which seems likely but is not yet certain), then OGSI becomes obsolete. All software based on OGSI is then obsolete and would need to be rebuilt to use WS-RF. WS-RF agents and services would not interoperate with OGSI agents and services; the SOAP messages are incompatible.

WS-RF is an attempt to make the ideas and features of OGSI compatible with IT-industry standard for web services. Aspects of OGSI such non-standard WSDL mean that normal SOAP tools work badly with OGSI services. Other aspects, such as the novel use of services URLs to identify per-user state, make OGSI services incompatible with higher-level web-service standards such as WS-Transaction. WS-RF makes grid services syntactically compatible with the other tools and services. It does this by addressing state not by tweaking the service URL but via special tokens in the SOAP headers. WS-RF may not be semantically compatible with other standards; the debate about that continues. However, it seems to be possible to build software that uses both WS-RF and, say, WS-Transaction to get the benefits of both systems.

WS-RF is built on WS-Addressing, the latter being an established OASIS standard. Therefore, any WS-RF system would be able to exploit WS-Addressing to navigate firewalls etc. at little extra cost.

There is no published implementation of WS-RF. The plan described yesterday, at the seminar in London, is to release Globus Toolkit 4 based on WS-RF in 3Q2004. IBM have promised to support WS-RF in WebSphere. The University of Virginia, who publish an OGSI implementation for .NET, have announced an intention to do WS-RF for .NET. There may well be other implementations planned or in progress.

In fact, WS-RF may be fairly easy to implement given an existing implementation of WS-Addressing. It is possible that less toolkit support is needed than for OGSI because WS-RF is a cleaner standard.

It is not yet known where WS-RF would be standardized. It could be in OASIS, it could be in GGF, it could be some joint effort. The specifications are expected to undergo two or three months of refinement by the original authors before submission for standardization.

OGSA (as opposed to OGSI) will presumably have to be redefined in terms of WS-RF. OGSA-DAI will definitely get refactored to use WS-RF, starting from version 4.

The Globus project's summary of WS-RF is available on their web site. Their summary has links to the initial specifications for the parts of WS-RF.

-- GuyRixon - 29 Jan 2004