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Wednesday 12th October 2005
COMMENTARY: WS-STAR STARTS TO SHINE
| In a service oriented environment a commercial transaction will generally involve two parties exchanging information that allows their separate business processes to operate in a collaborative manner. In a supply chain a supplier receives information on requirements and responds with an agreement to supply. The buying organization is managing the state of the procurement process and the supplier is managing the state of the sales process. In the simplest of situations the buying organization needs to confirm the order with the procurement process only when the selling organization has committed to supply and of course set the sales order state as confirmed. In the process we can imagine there may be several exchanges which relate to price, quantity and delivery date before the transaction is committed. What WS-TX does is allow the co-ordination of multiple exchanges in a long running transaction composed of multiple atomic transactions, allowing the parties to manage the integrity of the complete business transaction in their separate business processes.
Given this very reasonable requirement you might imagine that this very basic business need would have been the highest priority for Web Service protocol development. But of course it’s not as simple as that - there has been competition between vendors in setting the standards in this area. There are existing OASIS TC’s in the form of WSRM and WS-CAF (Composite Application Framework) that feature similar specifications that overlap with WS-RX and WS-TX respectively. This situation, with BEA, IBM, Microsoft and others promoting the specifications in WS-RX and WS-TX on one side (as well as implementing them in their products), and IONA, Oracle, Sun, and partners on the other has been a source of confusion for customers who, if survey evidence is to be believed, place uncertainty over Web Service protocol standards high on their list of inhibitors to adoption.
CBDI Forum has consistently advised that the protocol specifications coming from IBM and Microsoft together with relevant partners in each spec stand the best chance of adoption in the market. Users are clearly looking for a single “standard”, not a choice. It is therefore welcome that the announcement of WS-TX includes participation of IONA and Oracle. With members of WSRM also moving to support WS-RX it looks as if convergence around a single set of protocols for secure, reliable, transactions should now be forthcoming.
Interestingly work in the WS-CAF TC will not stop. The WS-TX committee will deliver the co-ordination framework and specific co-ordination types for atomic transactions and business activities, whilst the WS-CAF committee will continue to work on additional types and other complementary extensions.
A key advantage of WS-TX is the combination of security, reliable messaging and addressing protocols have all been designed to work together – hence WS-STAR. There has been significant engineering on how these specifications are combined such as how are they layered together and what is the order of precedent? For example WS-TX specifies exactly how to secure transaction messages using WS-Security, whereas in WS-CAF the security mechanism was left unspecified.
Today, implementations of WS-STAR are already available to early adopters, and interoperability workshops have already been completed by the vendors. Although the TC has only just been formed any critical flaws in the specification should have been identified by now. Going forward the standards process should one of refinement, and adding to the specification such as documenting additional use cases, rather than reengineering the protocols.
It seems likely that the combined WS-STAR standards should be approved in 2006. One significant driver for this timescale will be the planned commercial availability of Windows Vista late in 2006 which includes implementations of WS-STAR in the Windows Communications Framework (WCF). For many organizations the practical realization of WS-STAR will be a significant milestone on their SOA roadmap.
LINKS
OASIS WS-TX TC
OASIS WS-RX TC
OASIS WS-Security TC | | The acronym WS-STAR (or WS-*) is widely used to refer to the set of protocols required to enable secure, reliable, asynchronous transactions to be conducted without creating dependencies on a common messaging middleware or transaction processor. In other words WS-STAR represents a baseline for pretty much any normal commercial transaction. WS-Security has been around for some time, whilst the WS-RX (Reliable Exchange) Technical Committee (TC) was formed earlier this year. The announcement this week of the OASIS Web Services Transaction Technical Committee WS-TX TC sees the final piece of the WS-STAR jigsaw put into place. |
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