The 2nd hand enterprise architecture

Naming this post “the 2^nd hand enterprise architecture” is sure to make a few eyebrows rise. The intention is to bring attention to assets that already exist in the organization and may be reused for creating first-cut enterprise architecture. Ambler, Nalbone, and Vizdos (2005) states that existing enterprise architecture assets may be used to speed up, or kick-start, the development of the first-cut enterprise architecture.

Reusable assets may include reusable domain components, collections of related domain/business classes that work together to support a cohesive set of responsibilities, or service domains which bundle a cohesive collection of services together, existing security frameworks, existing vertical frameworks (e.g. financial frameworks), documented approaches and patterns to solve common problems, collections of classes that implement the basic functionality of a common technical, or business domain, and previously created development artifacts – functional specifications, standards documents, domain-specific models, procedures and guidelines, and even other applications such as a commercial off the shelf (COTS) packages (Ambler et al. 2005).

Ambler et al (2005) cautions that the use of pre-existing artifacts may lock the enterprise architecture team into specific frameworks, methodologies, standards and guidelines, but that it will accelerate the development of enterprise architecture. They further advise that research upfront may bring to light many reusable assets, especially if the enterprise has a track record of formal development methodologies and process. The following figure explains categories of re-use. An architecture description using UML forms the basis of this approach.

Alternatively, architecture (IT architecture) may be reconstructed from legacy systems. Seacord, Plakosh and Lewis (2003) states that architecture reconstruction allows for the creation of system architecture and views on it. It is a process of reverse engineering that assists in recovering architecture assets.

Research into existing artifacts that possibly may be reused may include investigations into:

• Documented strategy
• Documented business process
• Quality process (ISO, CMMI, etc)
• Governance process (Sabanes-Oxley, Basel II)
• Legacy architecture
• Others

Apart from the possibility that reuse of existing architecture assets may have constraints, it may be a rapid kick-start to establishing a first cut enterprise architecture. It enables a jigsaw puzzle approach that allows for quickly building a picture, understanding what pieces are missing and then completing the picture.

References:

Ambler S.W., Nalbone J., Vizdos M.J. (2005), The Enterprise Unified Process: Extending the Rational Unified Process, Prentice Hall

Seacord R.C., Plakosh D., Lewis G.A. (Author), Modernizing Legacy Systems: Software Technologies, Engineering Processes, and Business Practices, Addison-Wesley Professional