Remember a couple of years back when the vendors lined up in factions to fight over specifications?
- WS-Reliability vs WS-ReliableMessaging
- WS-CAF vs WS-Transaction
- WS-MessageDelivery vs WS-Addressing
- Liberty/SAML vs WS-Trust/WS-Federation
The situation is much improved since Microsoft and Sun buried the hatchet two years ago, and IBM and Microsoft have finally submitted most of their specs (WS-SX, WS-RX, and WS-TX) to OASIS.
But there's still one outstanding competing specification stack that still need to be resolved: that of resources, events, and management. Unlike previous situations, in this case IBM and Microsoft are on different sides--and the dispute revolves around simplicity vs richness.
The two stacks line up like this:
The Microsoft stack is lighterweight and was only recently placed on a standards track. (WS-Management is now governed by DMTF, and WS-Transfer, WS-Enumeration, and WS-Eventing were submitted to W3C in mid-March.) The IBM stack focuses on richness of functionality and is being managed by OASIS. WSDM is an OASIS standard.
I find the management dicotomy particularly unsettling, so I was very pleased to see HP, IBM, Intel, and Microsoft publish a white paper that I refer to as WS-Convergence. It defines a roadmap for converging these specifications. (A realistic timeframe for completion of this roadmap is 24-36 months.)
The roadmap is divided into three sections, addressing resource management, event processing, and management.
Resource Management: The roadmap proposes using WS-Transfer and WS-Enumeration as the standard foundation for resource management. The roadmap also proposes developing two new specifications, WS-Transfer Addendum and WS-ResourceTransfer, as well as a revision of WS-MetadataExchange.
- WS-Transfer Addendum will extend WS-Transfer to add support for WS-Addressing endpoint references
- WS-MetadataExchange v1.1 will build on WS-Transfer and WS-Transfer Addendum in place of its current domain-specific protocol
- WS-ResourceTransfer builds on WS-Transfer, WS-Transfer Addendum, WS-Enumeration, and WS-MetadataExchange, providing sophisticated resource management capabilities comparable to those of WSRF
All four vendors promise to deliver products that support these specifications. IBM further commits to influence the OASIS WSRF TC to refactor the WSRF specifications into extensions that build on WS-ResourceTransfer.
Event Processing: The roadmap proposes using WS-Eventing as the standard foundation for event processing. It also proposes developing a new specification, called WS-EventNotification, that will integrate many capabilities from WS-Notification into WS-Eventing. WS-EventNotification builds on WS-ResourceTransfer to support resource management of subscriptions.
All four vendors promise to deliver products that support WS-EventNotification. IBM intends to influence the OASIS WS-Notification TC to ensure compatibility between WS-EventNotification and WS-Notification, although WS-Notification will most likely continue on its own trajectory to support more complex use cases.
Management: The roadmap proposes the development of a new management specification that builds on WS-EventNotification and WS-ResourceTransfer. The new specification will replace both WSDM and WS-Management.
All four vendors promise to deliver products that support the new converged management specification. In addition, IBM will continue to support WSDM, and Microsoft will continue to support WS-Management.