Article Essential Layers, Artifacts, and Dependencies of Enterprise Architecture
By Robert Winter and Ronny Fischer
Abstract After a period where implementation speed was more important than integration, consistency and reduction of complexity, architectural considerations have become a key issue of information management in recent years again. Enterprise architecture is widely accepted as an essential mechanism for ensuring agility and consistency, compliance and efficiency. Although standards like TOGAF and FEAF have developed, however, there is no common agreement on which architecture layers, which artifact types and which dependencies constitute the essence of enterprise architecture. ...view middle of the document...
) as well as (2) the principles governing its design and evolution (Opengroup 2003) . While an EA model is a representation of as-is or to-be architecture of an actual corporation or government agency, an EA framework provides (Opengroup 2003) • One or more meta-model(s) for EA description,
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One or more method(s) for EA design and evolution, A common vocabulary for EA, and maybe even Reference models that can be used as templates or blueprints for EA design and evolution.
The components of an EA framework should be applicable for a broad range of corporations and government agencies. Traditionally, architecture in the information systems context is focusing on IT related artifacts like IT platforms, software components and services, applications, IT processes, and maybe IT strategy in order to support more efficient IT operations, better return on IT investment, and faster, simpler and cheaper IT procurement (Opengroup 2003). In contrast to this approach which better should be designated information systems architecture (ISA), EA should also include business related artifacts like organizational goals, products and services, markets, 1
© Journal of Enterprise Architecture – May 2007
business processes, performance indicators, etc. (Braun/Winter 2005). Only when ‘ purely’ business related artifacts are covered by EA, important management activities like business continuity planning, change impact analysis, risk analysis and compliance can be supported. ENTERPRISE ARCHITECTURE: REPRESENTATION The aforementioned definition of enterprise architecture restricts included components to be ‘ fundamental’ Due to the broad range of rele. vant component types, EA may nevertheless comprise a huge number of such artifacts. As a consequence, most EA frameworks distinguish several architecture layers and architecture views in order to reduce the number of artifacts per model (Schekkerman 2004, Tang et al. 2004). When several architecture layers and architecture views are differentiated, design and evolution principles have to address consistency and integration issues. The theory of hierarchical, multilevel systems (Mesarovic et al. 1970) provides a conceptual foundation for such methods. For EA, a hierarchical approach usually applies the ‘ follows business’principle, starting with IT strategic positioning from the business management point of view, then deriving appropriate organizational processes and structures on this basis, and finally specifying the information system, i.e. the interaction between human and technical information system components that appropriately support business requirements (Braun/Winter 2005). Most frameworks differentiate the following EA layers: • Business architecture: The business architecture represents the fundamental organization of the corporation (or government agency) from a business strategy viewpoint. Typical artifacts represented on this layer are value networks, relationships to customer and...