7. Complete the architecture definition

Objective    Approach     Inputs     Activities    Outputs

Objective

The objective of this step is to fully specify the target architecture. This is a complex and iterative process in which the selection of building blocks and interfaces has a big impact on how the original requirements are met. Figure 2 shows this as two boxes, captioned as steps 7a and 7b, but in reality the process is more complicated. See Part IV, Building Block Example, for further details.

Approach

Completion of the architecture definition may be achieved in two steps, by defining an intermediate migration architecture in addition to the final target architecture, if complexity of migration requires it.

The specification of building blocks as a portfolio of services is an evolutionary process:

• The earliest building block definitions start as relatively abstract ones, defined by standards and services that map most easily to the architectural framework. These building blocks are most probably architectural building blocks.
• At this stage a model and a portfolio of services have been established. The next step is to select the set of specifications that provide the services and that can be combined as required to create the building blocks.
• During this final step in the development of building blocks it must be verified that the organization-specific requirements will be met. The development process must include recognition of dependencies and boundaries for functions and should take account of what products are available in the marketplace. There are architectural and related solution oriented building blocks.
• An example of how this might be expressed can be seen in the Building Blocks Example in Part IV. Building blocks can be defined at a number of levels matching the degree of integration that best defines the architecture of the system at any stage.
  • Fundamental Functionality and Attributes - semantic, unambiguous including security capability and manageability
  • Interfaces - chosen set, supplied (APIs, data formats, protocols, hardware interfaces, ...standards)
  • Dependent BBs with required functionality and named used interfaces
  • Map to business / organizational entities and policies
• Finally the building blocks become more implementation specific as Solution Building Blocks and their interfaces become the detailed architecture specification. Solution Building Blocks are a means to determining how portions of the target architecture might be procured, developed, or reused. The Solution Building Blocks architecture should have separate elements for developed, reused and procured building blocks, each described in terms of their minimum specification.

A full list of standards and specifications recommended by The Open Group can be found in Part III, Standards Information Base.

Inputs

The inputs to this step are:

• Business Architecture Version 2
• Technical Architecture Version 0.6
• Re-usable architecture building blocks (from organization's Architecture Continuum, if available)
• TOGAF Standards Information Base

Activities

Key activities in this step include:

1. Ensure clear documentation of all interfaces for each building block (APIs, data formats, protocols, hardware interfaces).

2. Select standards for each interface of the architecture building blocks, reusing as much as possible from TOGAF TRM.

3. Fully document each architecture building block.

4. Final cross check against business goals.

5. Document final requirements traceability reports

6. Create final mapping of the architectures within the architecture continuum.

Outputs

The outputs of this step are:

• Technical Architecture Version 0.7
  • Technical Architecture - Technical Architecture Specification
  • Technical Architecture - Requirements Traceability
  • Technical Architecture - Mapping of the architectures in the architecture continuum.

Step 8: Conduct gap analysis

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