Key takeaways
- ABB = required capability; SBB = implementation component.
- ABBs shape the specification of SBBs, never the reverse.
- Definition happens mainly in A, B, C, and D, iteratively.
- Phases B, C, D follow four steps, ending with gap analysis.
- In Phase E, building blocks join the work packages.
What a building block is, and what it brings
A building block bundles functionality designed to serve the organization's business needs. It has a metamodel type (actor, business service, application, data entity…), a clear boundary, and domain experts recognize it as a "thing". It may interact with other building blocks it depends on.
Architecture Building Blocks group, at the functional level, what the requirements call for; Solution Building Blocks are products that can be bought or specific developments. An ABB describes the required capability and shapes the specification of SBBs: a customer services capability may be delivered by several SBBs (processes, data, software).
Well chosen, building blocks ease legacy integration, interoperability, and flexibility in creating new systems.
A good building block
The standard expects a building block to take its implementation and usage into account, and to evolve to exploit technology and standards. It can be assembled from other blocks or fit into a larger whole. Ideally, it is re-usable, replaceable, and well specified.
- Metamodel type and defined boundary
- Considers implementation and usage
- Composable: assembled from or part of other blocks
- Re-usable, replaceable, well specified
The path through the phases
Definition is evolutionary and iterative. Phase A starts with abstract entities. It continues mainly in B, C, and D, because required functions, constraints, and product availability, discovered along the way, can change the choice and content of blocks. The major work is identifying the ABBs that serve the Business Goals, then refining them into bought or built SBBs.
In Phases B, C, and D, the same four-step pattern repeats. In Phase E, building blocks are associated with the work packages that will close the gaps.
- 1. Select reference models, viewpoints, and tools
- 2. Baseline: high-level model of existing blocks, re-using the Repository
- 3. Target: catalogs, matrices, diagrams; document and justify each block; re-use; choose standards from the Architecture Continuum; map to the Landscape; publish re-usable blocks
- 4. Gap analysis: blocks carried over, eliminated, new; realization approach for each gap
TERMS TO KNOW
The terms, in context.
- Architecture Building Block (ABB)
- Functional grouping describing a required capability, independent of products.
- Solution Building Block (SBB)
- Concrete component, bought or developed, that implements a required capability.
- Boundary
- Defined limit of a building block, stating what it covers and how it interacts.
- Realization approach
- Decision taken for each gap: develop or procure the missing building block.