From Layers to Slices: Redirecting EA Dimensions

Gostei muito deste post do Janne J. Korhonen, editado no blog http://www.ebizq.net! Ele consubstancia nossa metodologia da Arquitetura-Governança-Crescimento (ver   http://www.creativante.com.br/lettericia/blog/2009/45_2009.html) como uma ferramenta cada vez mais robusta para interpretar a organização e a dinâmica das empresas que se apóiam fortemente em TICs.

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From Layers to Slices: Redirecting EA Dimensions

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By Janne J. Korhonen on December 6, 2009 12:57 PM 

An enterprise architecture framework provides tools and methods to structure, classify and organize the enterprise architecture through a coherent set of views on relevant EA artifacts and their relationships. Enterprise-class description frameworks such as TOGAF or Zachman Framework distinguish several architecture layers and architecture views to disentangle the vast complexity and reduce the number of artifacts per model.

EA frameworks typically recognize three or four architectural dimensions that are used to structure architecture products. These dimensions typically include:

  • Business Architecture
  • Information Architecture
  • Information Systems Architecture
  • Technology Architecture

In many cases, these architectural dimensions are viewed as layers of the enterprise architecture, as depicted in Figure 1.

Figure 1. Layering the Enterprise Architecture by architectural dimensions.

This hierarchical approach is based on the tenet of ‘IT follows business’: business processes and organizational structures follow the strategy, are implemented in and supported by information systems, which, in turn, are supported by technical infrastructure. While this mindset may be useful in categorizing IT artifacts, it falls short in aligning IT architecture with IT strategy and with business architecture artifacts such as vision documents or business models. The technology dimension may also be missed in business architecture; high-level IT decisions need to be made in consideration of both business and technology.

Lindström et al. (2006) surveyed the concerns of Swedish CIOs and how well enterprise architecture frameworks supported these concerns. According to their study, the most notable disharmony between the CIOs prioritized concerns and the foci of EA frameworks lies in the lack of support for issues related to the IT organization. IT organization-related issues such as IT governance, IT procurement and development processes, and IT project portfolios should be better incorporated in the EA models.

The EA Grid by Pulkkinen and Hirvonen (2005) recognizes this need and addresses not only the artifacts but also architectural decisions at different organizational levels. The framework layers the enterprise architecture by three decision-making levels (Enterprise, Domain and System) that are crossed by the four widely accepted architecture dimensions (Business, Information, Systems and Technology). While I highly resonate with their overall approach of building the EA framework on architectural decision-making, I am in some disagreement with their interpretation of levels and how the grid is populated.

I would identify four levels as shown in Figure 2, in line with the governance model outlined before. In my next blog post, I will outline what artifacts and what architectural decisions would pertain to each level by each dimension.

Figure 2. EA framework layered by decision-making levels.

References

Lindström, Å, P. Johnson, E. Johansson, M. Ekstedt & M. Simonsson (2006). “A survey on CIO concerns-do enterprise architecture frameworks support them?”, Information Systems Frontiers, Vol. 8, No 2. February 2006.

Pulkkinen, M. & A. Hirvonen (2005). “EA Planning, Development and Management Process for Agile Enterprise Development” in System Sciences, 2005. HICSS ’05. Proceedings of the 38th Hawaii International Conference on System Sciences – 2005.

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