A two-tier campus architecture, commonly called a collapsed-core design, combines the core and distribution functions into a single logical network layer.

This architecture is particularly suitable for smaller campus environments where individual buildings contain relatively few wiring closets and the overall network does not require a separate core infrastructure.

Option B accurately describes such an environment.

In a two-tier design, access switches connect directly to the collapsed core, typically through redundant uplinks.

HPE Aruba Networking supports highly available collapsed-core architectures using suitable AOS-CX switches configured with VSX.

This provides resilient forwarding, redundant uplinks, and simplified network management without requiring an additional distribution-to-core layer.

Option A indicates that the collapsed core can no longer accommodate aggregate traffic requirements, which may justify moving to a three-tier architecture.

Option C similarly describes aggregation capacity limitations that may require redesign or additional switching capacity.

Option D indicates campus growth beyond a small number of building aggregation points, increasing the potential benefits of a dedicated core layer.

The architect should select the topology according to scale, physical distribution, expected traffic, resilience requirements, and operational complexity rather than assuming that a three-tier architecture is always preferable.

Official HPE Reference: HPE Aruba Networking Campus Design Validated Solution Guide — LAN Design, Two-Tier Collapsed Core and Three-Tier Campus Architectures.

Validated Solution Guide

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