Friday, December 12, 2003

SOA and Enterprise Architecture

The old-style IT practitioner always regarded distribution as a source of complexity, and instinctively preferred non-distributed solutions wherever possible. The Service-Oriented Architecture turns this attitude on its head. The whole point is to distribute functionality across a network of services.

The well-known Zachman framework for Enterprise Architecture has a column for Network, but historically this has generally been regarded as referring to geographical location. Zachman himself calls this column “Where” – the other columns being Data (“What”), Function (“How”), People (“Who”), Time (“When”) and Motivation (“Why”).

But in a fully service-oriented economy, we must abstract away from geographical location. Web Services and related technologies allow the geographical location (and other physical locators) to be completely transparent. Instead, we can now interpret “Where” as referring to locations within an abstract topology or network.

In the service-oriented business we regard the enterprise as a (possibly federated) network of services. It is not geographical distance that matters any more, but abstract notions of distance, including commercial and semantic distance.

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