Phase C: Information System Architectures (Introduction)

Objective  Approach     Inputs     Steps    Outputs

Objective

The objective of this phase is to develop target architectures covering either or both (depending on project scope) of the Data and Application Systems domains.

The scope of the business processes supported in this phase is limited to those that are supported by information technology, and the interfaces of those IT-related processes to non-IT-related processes.

Approach

Development

This phase involves some combination of Data and Applications Architecture, in either order. Advocates exist for both sequences.

For example, Spewak’s Enterprise Architecture Planning recommends a data-driven approach.

On the other hand, major applications systems such as those for Enterprise Resource Planning, Customer Relationship Management, etc., often provide a combination of technology infrastructure and business application logic, and some organizations take an application-driven approach, whereby they recognize certain key applications as forming the core underpinning of the mission-critical business processes, and take the implementation and integration of those core applications as the primary focus of architecture effort (the integration issues often constituting a major challenge).

Implementation

Implementation of these architectures may not necessarily follow the same order. For example, one common implementation approach is top-down design and bottom-up implementation:

• Design:
  1. Business Architecture design
  2. Data (or Applications) Architecture design
  3. Applications (or Data) Architecture design
  4. Technical Architecture design
•  Implementation:
  1. Technical Architecture implementation
  2. Applications (or Data) Architecture implementation
  3. Data (or Applications) Architecture implementation
  4. Business Architecture implementation

An alternative approach is a data-driven sequence, whereby application systems that create data are implemented first, then applications that process the data, and finally applications that archive data.

Inputs

Inputs to this phase are:

• Applications Principles (if existing)
• Data Principles (if existing)
• Request for Architecture Work
• Statement of Architecture Work
• Architecture Vision
• Enterprise Continuum
• Business Baseline - Version 2 (detailed) - if appropriate
• Target Business Architecture - Version 2 (detailed)
• Relevant technical requirements that will apply to this phase
• Gap analysis (from Business Architecture)
• Re-usable building blocks (from organization's Architecture Continuum, if available)

Steps

Detailed steps for this phase are given separately for each architecture domain:

• Data Architecture
• Applications Architecture

Outputs

The main outputs are as follows:

• Statement of Architecture Work   (updated if necessary)
• Target Data Architecture
• Target Applications Architecture
• Data Architecture Views corresponding to the selected viewpoints addressing key stakeholder concerns
• Applications Architecture Views corresponding to the selected viewpoints addressing key stakeholder concerns
• Data Architecture Report, summarizing what was done and the key findings
• Applications Architecture Report, summarizing what was done and the key findings
• Gap analysis
  • Areas where the Business Architecture may need to change to cater for changes in the Data and/or Applications Architecture
  • Constraints on the Technology Architecture about to be designed.
• Impact Analysis
• Updated business requirements (if appropriate)

Copyright © The Open Group, 2002