The most interesting story from Microsoft's recent Professional Developers Conference wasn't the vendor's future Longhorn operating system, but rather, Microsoft's shift away from two preoccupations of its recent past: .Net and Web services.
Microsoft isn't abandoning the .Net Framework or Web services standards in its development, hosting and interoperability environments. The .Net Common Language Runtime (CLR), .Net class libraries and growing WS-* standard suite are still expected to be core features of the future Longhorn client and server releases.
But the vendor has distanced itself from the terms .Net and Web services and has incorporated these frameworks in a broader-umbrella architecture associated with Longhorn. This uber-framework, called WinFX, refers to the new APIs and component model underlying the new operating system. WinFX, like .Net, will be supported on prior Windows operating systems through downloadable components.
WinFX will expose the functionality of an important new protocol-interoperability framework -- Indigo -- that sits at the heart of Longhorn. What's significant about Indigo is that it embraces, integrates and bridges the full range of middleware protocols that Microsoft has built into its operating system.
Within the Indigo environment, the Web services framework (WSF) is the dominant approach, but not the only approach, for integrating applications. Indigo encompasses all core WSF standards and protocols -- principally XML, Simple Object Access Protocol (SOAP), Web Services Description Language and Universal Description, Discovery and Integration -- and everything else that's being developed under the WS-* heading. But Indigo also will let older Windows-based applications interoperate with newer WinFX applications.
Indigo uses service-oriented architectures (SOA) to bridge WSF and other middleware approaches and protocols. Fundamentally, an SOA is any interoperability environment in which autonomous applications expose their interfaces through standard service contracts, publish these contracts through shared service registries and interact through exchange of messages that contain data in agreed-on schemas, such as SOAP/XML. Indigo leverages these core WSF standards to make SOAs span and bridge WSF and non-WSF middleware environments.
Flexibility is the core architectural feature of Indigo. This new interoperability framework will support loosely coupled WSF and message-brokering interactions among application components, but it also will enable the sort of tightly coupled remote object interactions traditionally associated with DCOM, .Net Remoting and other object-brokering protocols. Indigo will support cross-domain, wide-area application integration across diverse machines, but also will scale down to support process integration within one server. It specifies SOAP/XML as the mandatory in-memory data format, but lets that format be serialized to almost anything you wish for transmission. It spans transports, security systems, messaging patterns, encodings, network topologies, interceptor models and hosting models.
Clearly, Indigo is largely a Microsoft initiative to get its internal middleware house in order. But Microsoft, through its Indigo vision, also seems to be hinting to the industry at large that the WS-* stack is too narrow. WS-*, of which Microsoft has been a prime developer, needs to incorporate support for tightly coupled, synchronous object-brokering approaches to support a broader range of integration scenarios.
Indigo convincingly brings object computing into the new world of SOAs. Although a proprietary architecture associated with Microsoft operating systems, Indigo is applicable to SOAs that span diverse operating and application platforms. This powerful new interoperability vision should serve as a blueprint for the future evolution of WS-* standards.
- Kobielus is a senior analyst with Burton Group, an IT advisory service that provides in-depth technology analysis for network planners. He can be reached at firstname.lastname@example.org.