Monitor, Maintain, and Troubleshoot the Wireless Network
Monitoring and troubleshooting
Monitor the network at three layers: infrastructure health, RF health, and client experience. Use the controller dashboard, AP database, user table, and alarm logs; use AirWave or Central for long-term trends. RF health includes channel utilization, noise floor, retries, SNR, and ARM/AirMatch channel changes. Client troubleshooting follows the join sequence: discovery, association, authentication, DHCP, role/policy, and data path. Find the first failing step rather than guessing.
Useful CLI checks include show ap database, show ap active, show user-table, show datapath session table, show log all, and client debug commands. Packet capture at the controller or AP helps confirm whether DHCP, DNS, or EAP traffic is present. Check NTP and time zones so logs correlate, and verify licensing and AP whitelist status.
Traps: looking only at RSSI when retries and channel utilization explain poor performance; forgetting that a client can associate but fail DHCP because the VLAN is missing on the trunk; and applying debug commands without limiting output.
Worked example
A client associates but gets no IP address. Confirm the client is in the user table, check its role and VLAN, verify the VLAN exists on the controller and uplink trunk, then check the datapath session table for DHCP. If DHCP discover is absent, inspect the firewall policy; if present but no offer, check the VLAN and DHCP helper.