Phase D: Technology Architecture is the final BDAT architecture phase. Product selection may occur in Phase D (e.g. re-using existing products or adding capacity); significant or non-standard product choices are flagged as opportunities for Phase E. It adds the Technology Architecture section to the draft Architecture Definition Document, which is finalized in Phase F.
Phase D develops the Technology Architecture — the infrastructure, platforms, and technology standards that host and enable the Application Architecture defined in Phase C. Product selection may occur in Phase D (e.g. re-using existing products or adding capacity). Significant or non-standard product choices are flagged as opportunities for Phase E.
- ▸🖥️ Develops Baseline Technology Architecture (current infra As-Is)
- ▸🎯 Develops Target Technology Architecture (future infra To-Be)
- ▸🔍 Performs Technology Gap Analysis (New tech / Upgrade / Retire / Retain)
- ▸📄 Completes the Architecture Definition Document (adds Technology Architecture section)
- ▸🔗 Identifies technology building blocks and may select products; the overall SBBs are defined in Phase E based on the ABBs
- ▸📏 Defines Technology Standards (approved products list, version standards)
- ▸🗺️ Updates Architecture Roadmap with technology-specific work packages
See how CDIPD's Phase C application components were matched to candidate products in Phase D, with the SBB decision finalized in Phase E (product names are illustrations). Click each component to see the candidate and why:
Identity & Access Management
A capability providing centralised authentication, authorisation, and Single Sign-On across all enterprise applications.
Deployed on Kubernetes at CDIPD — handles Keycloak SSO for DWMS, PayFlask, VSSC.
Cloud-based identity service — alternative SBB that fulfils the same ABB.
Another valid SBB — swap Keycloak for Auth0 and the ABB requirement still holds.
One ABB can be fulfilled by multiple SBBs. You can swap one SBB for another without changing the ABB — this is what makes architectures technology-agnostic and future-proof. The ABB is the contract; the SBB is the implementation choice.
Phase D produces three categories of technology architecture work products — catalogues, matrices, and diagrams — which together form the Technology Architecture section of the ADD.
- ▸📋 Catalogues: Technology Standards Catalogue (approved products + versions), Technology Portfolio Catalogue
- ▸⬛ Matrices: Technology/Application matrix, Application/Technology Dependency matrix
- ▸📊 Diagrams: Infrastructure/Technology diagram, Platform Decomposition diagram, Network/Hardware diagram, Environments/Locations diagram, Communications Engineering diagram
- ▸📏 Technology Standards Catalogue: the approved products list — what versions of what products are approved for use
- ▸⚠️ These are artifacts contained within the ADD deliverable (same Artifact vs Deliverable distinction as Phase B/C)
The ADD is built progressively across all four BDAT phases. Phase D adds the last domain section; the ADD stays a draft through Phase E and is finalized in Phase F.
- ▸✅ ADD Section 1: Business Architecture (Phase B) — What the business does
- ▸✅ ADD Section 2: Data Architecture (Phase C) — What data entities exist
- ▸✅ ADD Section 3: Application Architecture (Phase C) — What applications handle the data
- ▸✅ ADD Section 4: Technology Architecture (Phase D) — How technology hosts the applications
- ▸📌 Phase D output = Draft ADD; the Finalized ADD is a Phase F output
- ▸🔑 Exam: "Which phase outputs the Finalized ADD?" = Phase F
The Technology vs Application Architecture distinction is tested throughout OGEA-101. Phase D is where this distinction becomes most visible:
- ▸📱 Application Architecture (Phase C): "A workflow engine that routes tasks via configurable approval chains"
- ▸🖥️ Technology Architecture (Phase D): "Spring Boot 3.x microservice on Docker, deployed to Kubernetes v1.28 cluster"
- ▸🗄️ Application Architecture: "A relational data store for DWMS entities"
- ▸🖥️ Technology Architecture: "PostgreSQL 16 on dedicated bare-metal server with pg_dump daily backup"
- ▸🔑 Rule: Logical, vendor-neutral = ABB. Physical / supplier-specific = SBB. SBBs are formally defined in Phase E
- ▸⚠️ Exam trap: "PostgreSQL" in Phase C = wrong; "PostgreSQL 16" in Phase D = correct