Existing Architecture Analysis is the process of leveraging existing architectural assets (e.g. existing architecture
definitions within the enterprise) as well as industry or enterprise standards, models and assets in order speed up the
definition of a new IT architecture. Using this bottom-up approach, Existing Architecture Analysis identifies and
validates candidate roles, functions, entities, locations and flows. Technical constraints related to existing
systems should also be evaluated, again for speeding up the architecture process and for risk management
purposes. Analyzing technical and enterprise (AD) constraints should be done early in this analysis.
If an Architectural Summary has already been defined, then this task (following the steps defined below) updates it
based upon the new and revised IT Architecture models.
Steps
Identify Components & Patterns
This first step involves a quick review of existing architecture or project documentation of existing assets. The
architectural components, in terms of business entities, business processes, business locations and business roles are
identified. Similarly the components at the logical and technology layers are identified and documentation extracted
(i.e. logical/technical data, logical/technical processes, logical/technical systems and logical/technical roles).
Architectural patterns are also identified (e.g. n-tier or client-server, etc.).
Enough information is extracted to support the next step.
Document Components & Patterns
This step uses the extracted information from the previous step to produce an architectural summary document. The
relevant architectural components, in terms of business entities, business functions, business locations and business
roles are documented. Architectural patterns are also documented (e.g.n-tier or client-server, etc.).
Structure Components & Patterns
The now documented architectural components are structured in terms of interdependencies and interactions, completing the
summary of the architectural extract.
Properties
Multiple Occurrences
Event Driven
Ongoing
Optional
Planned
Repeatable
Usage Guidance
In the context of doing a gap analysis in order to do migration planning one needs to document an existing architecture in
order to compare the existing situation to the desired end-state as defined in the enterprise architecture. Not only are
architectural decisions a good source of information, existing project and system documentation is invaluable in helping
document an existing architecture.
