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Indigo: The Longhorn Communications Layer

Posted December 18, 2003

Indigo is the core for communication in the next generation of Windows, code-named Longhorn (see Figure 1). It builds on Microsoft's vision of service-oriented architecture, which itself relies on the Web Services Enhancements (WSE) 2.0 specification for the next generation of Web services. It might not be clear from the diagram, but Indigo supports both a Web service-based and a remoting-based approach to communication. This architecture—and its underlying technologies—is intended to supply a new level of security and power to service-based architecture.

The communication pillar also includes (1) collaboration, but that lies outside the Indigo model proper. The framework support for collaboration between programs and (2) people should offer significant opportunities to those who create the next generation of collaboration software.

One way to get a toehold into the complexity of Longhorn is to look for a feature you're particularly interested in. For example, you'll find (3) transactions embedded deeply in the base operating system (see the "Longhorn: The Base Operating System" object model), as well as in Indigo's systems services. Similarly, security support runs from the base operating system through the corresponding pillars, where appropriate.

The initial release of Longhorn is a client operating system, but the new Indigo features won't be too interesting if they are available only on client machines. They also need to be available on the server machines the clients interact with. To that end, Microsoft has also announced that key portions of the Indigo/WSE 2.0 specification will be available for Windows Server 2003. —Kathleen Dollard