Campus network reference architecture
A campus network typically separates access (endpoints/Wi-Fi), distribution or collapsed core (aggregation/policy), and a services/WAN edge. Overlay fabrics such as EVPN-VXLAN are optional and should be justified by scale and segmentation needs.
Key facts
- Audience: network architects and implementation engineers
- Goal: predictable segmentation, capacity and failure domains
- Non-goal: vendor BOM or priced SKUs
Summary
Layered campus design with clear underlay vs overlay decisions.
Audience
Enterprise network designers evaluating campus refresh patterns.
Prerequisites
- Inventory of buildings, closets and uplink capacities
- Security zoning requirements (guest, OT, corporate)
- Identity/NAC expectations if access control is in scope
Architecture
- Access: wired edge and wireless termination
- Distribution/core: aggregation, routing, policy enforcement points
- Services edge: Internet, WAN, DC interconnect, shared services
Components
Switches/routers capable of the chosen underlay; optional EVPN-capable leaves if overlay is selected.
Workflow
- Capture requirements and failure domains
- Choose underlay (L2 collapsed vs L3 routed) before overlays
- Map VLANs/VRFs or EVPN segments to security zones
- Define verification tests before cutover
Configuration
Vendor CLI is out of scope here. Use platform docs after the logical design is approved.
Verification
- Uplink utilization and ECMP balance checks
- Inter-VLAN/VRF policy tests
- Failover of dual-homed access uplinks
Troubleshooting
Start with underlay reachability and STP/ECMP state before blaming overlays.
Rollback
Keep a known-good underlay config checkpoint and dual-run critical VLANs during migration windows.
References
Related guides
- EVPN fabric overview — Spine-leaf EVPN-VXLAN fabric roles, fit criteria, and verification outline.
- EVPN-VXLAN technology — EVPN control plane with VXLAN data plane for scalable fabrics.
- Spine-leaf underlay pattern — Equal-cost multipath leaf-spine underlay used beneath overlays such as EVPN-VXLAN.
Owner: Novatelia Engineering / AEO Program. Reviewed: 2026-07-22. Doc version: 2026.07. Change log: Phase 6 technical authority pilot.
No datasheet copies, fabricated benchmarks, or unverified vendor authorizations appear in this document.