Routing, Switching, and Network Integration
Integration concepts
Candidates must understand how the controller integrates with the wired network: L2 vs. L3 deployment, VLAN pooling, GRE tunnels, and routing protocols (OSPF, static routes). Know how VRRP provides gateway redundancy and how PBR or policy routing can steer traffic. Understand DHCP relay/option 43 for AP discovery and DNS-based discovery.
Switching fundamentals
Review VLAN trunking, 802.1Q tagging, spanning tree, and LACP uplinks. Understand how AP management and user VLANs traverse trunks and how native VLAN mismatches break AP registration.
Traps
Questions often confuse AP discovery methods (DHCP option 43, DNS, broadcast) with user traffic forwarding. Another trap: assuming L3 deployment eliminates tunnels - clients may still be tunneled to the controller. Watch for VRRP priority/preemption mistakes and asymmetric routing when multiple gateways exist.
Rule of thumb
For AP discovery across subnets, configure DHCP option 43 with the controller IP or a resolvable DNS name; verify the AP can reach the controller's PAPI/UDP 8211 and tunnel ports. If APs register but clients fail, check user VLAN trunking and default gateway/VRRP state.
Verification
Confirm routing adjacencies, trunk allowed VLANs, and gateway redundancy state.