IT Solution Architecture

Overview

IT Solution Architecture involves engagement with IT solution delivery projects to confirm scope, solution options and architecture alignment, and to define the associated architecture specification (see IT System Architecture Definition). This engagement is managed through a Solution Architecture Governance process.

Solution Architecture Governance

The Solution Architecture Governance process defines architecture engagement in terms of the deliverables that must be produced and the key review points to validate the architecture and alignment of the subsequent design and solution implemented.

It should be mandatory for all business change driven projects but the extent of the engagement varies significantly depending on the extent of potential architectural impact. This may be determined by considering a variety of related factors, including:

  • Level of Investment
  • Impact to the Business
  • Impact to IT Architecture
  • Strategic Alignment
  • Problem / Solution Complexity

The review points and architecture deliverables can be defined with reference to the industry standard Unified Process for software development.

The Architecture Review (AR) points are as follows:

  • AR0: An initial review and assessment of the potential architectural impact and therefore subsequent engagement based on the first view of the proposed scope
  • AR1: A review of the High Level Architecture to confirm the proposed solution and further architecture engagement
  • AR2: A review of the Solution Architecture specification to confirm that this meets the requirements
  • AR3: A review of the detailed technical design specifications to confirm they are aligned with the Solution Architecture (which should have been updated if necessary)
  • AR4: A review of the final design to confirm Solution Architecture alignment as well as triggering any updates to the Enterprise Architecture

The architecture engagement determined during AR0, and which may be subsequently updated at AR1, can be expressed in terms of the final architecture review required. The following table defines typical scenarios and associated level of architecture engagement.

Architectural ImpactTypical ScenarioArchitecture DeliverablesAR Required
NoneSmall change to existing solutionNoneAR0
MinorLimited change to an existing solutionHigh Level ArchitectureAR0-AR1
SignificantLarge/structural change to an existing solutionHigh Level Architecture,
Solution Architecture
AR0-AR2
MajorNew solutionHigh Level Architecture,
Solution Architecture
AR0-AR4

High Level Architecture

The inception phase of project defines the scope, objectives, delivery plans and the high level business case to proceed. The IT solution scope is based on analysis of high level business requirements, and may require that various solution options be evaluated.

Architecture Governance mandates that an initial assessment (AR0) is conducted early on to determine the required architecture engagement. Based on the outcome of the concept review, it may be necessary to complete a High Level Architecture specification. This would typically include the following:

  • Identify key architectural requirements
  • Identify potential solution options, including related vendor application packages, to meet the requirements
  • Define relative architectural views of the solution options to be evaluated (see IT System Architecture Definition), focusing on differentiating aspects
  • Evaluate fit with existing / planned Enterprise Architecture (see Enterprise Architecture)
  • Evaluate alignment with relevant reference models, strategy and standards (if not already done so, these may be required to be defined)
  • Consider delivery related considerations (e.g. timescales, cost) for input into broader evaluation
  • Provide a recommendation on the preferred solution options from an architectural perspective
  • Define the high level solution architecture specification for the chosen option:
    • the specification may be composed in conceptual and/or informal terms or according the formal composition (see System Architecture Composition)
    • includes a view of application and platform architecture, but not detailed integration
    • delivery considerations for input into delivery approach and planning

The High Level Architecture is subject to review as per the governance framework, which means that it should be approved by appropriate enterprise architects and subject matter experts.

Solution Architecture

The elaboration phase of project defines detailed business requirements, solution architecture, functional design, logical system design and associated test strategy. It is only at the end of this phase where the solution scope is confirmed (notwithstanding further change requests), and that subsequent delivery plans can be finalised.

Based on the outcome of the initial architecture reviews (AR0 and AR1), it may be necessary to complete a ‘Solution Architecture’ deliverable, which is essentially an elaboration of the High Level Architecture produced for the chosen option during the inception phase. The purpose of this is to provide an overall solution blueprint that guides and directs more detailed functional and, in particular, technical design, and which includes the following:

  • Project Background
  • Architectural Requirements
  • Business Architecture (Process / function and information)
  • Application Architecture (Function & information placement, application interface, etc.)
  • Platform Architecture (Application services, supporting technology and infrastructure, platform interface, etc.)
  • Security Architecture (e.g. approach to user access management, data protection, etc.)
  • Alignment with Enterprise Architecture and related strategy & standards
  • Delivery Considerations

The business, application and platform specifications should be completed according the formal composition (see System Architecture Composition).

The Solution Architecture is subject to review as per the governance framework, which means that it should be approved by appropriate enterprise architects and subject matter experts. The Solution Architecture forms the basis for subsequent detailed design and solution development, which may be subject to further architecture review to ensure alignment, as prescribed by architecture governance.