Migration, Lifecycle, and Business/Operational Considerations
Lifecycle thinking
Architect-level questions expect you to plan across the whole lifecycle: plan, design, implement, operate, optimize, and retire. Know how to sequence a migration to minimize risk: inventory the current state, define the target, choose a migration pattern (big bang, phased by building/floor, parallel run, or pilot), and define rollback and acceptance criteria for each phase. Understand that decommissioning and documentation are part of the project, not an afterthought.
Migration patterns and risk
Common patterns include L2-to-L3 access migration, controller-based to cloud-managed wireless, and legacy WAN to SD-WAN. Each has dependencies: DHCP/DNS changes, authentication integration, routing adjacencies, and monitoring cutover. Traps include migrating technology without migrating operational processes (runbooks, on-call, monitoring), underestimating the need for a pilot, and forgetting that user-facing change windows drive the schedule more than technical readiness.
Business and operational considerations
Be ready for questions on total cost of ownership (hardware, licensing, support, operations), capacity planning, vendor and support lifecycle (end-of-sale, end-of-support dates), compliance and data residency, and change management. Operational readiness includes staffing and skills, documentation, backup of configurations, and a tested rollback plan.
Worked rule of thumb
For any migration, define the exit criteria for each phase before starting it, and require a tested rollback. If you cannot state how you would return to the prior state within the change window, the phase is not ready. Sequence by lowest-risk, highest-learning scope first (a pilot floor), then scale.