Monitoring, Troubleshooting, and Operations
What this domain covers
Operations is about keeping the campus healthy and fixing problems. Know the monitoring tools: device health dashboards, alerts, syslog, SNMP, and flow/telemetry data. Understand a structured troubleshooting method: define the problem, gather data, isolate the layer (physical, data link, network, application), and verify the fix. For wired issues, check link status, VLAN/trunk configuration, STP state, and PoE. For wireless issues, check client association, RSSI/SNR, channel utilization, co-channel interference, and roaming behavior. Know how to read basic outputs (interface status, ARP tables, client lists) and how to use packet capture at a high level.
Traps to watch
Questions often reward isolating the layer rather than jumping to a fix. A trap: assuming a wireless problem is RF when it may be a VLAN/DHCP issue (client associates but gets no IP). Another: overlooking that a trunk misconfiguration or STP blocking state can silently break connectivity. Also remember that intermittent issues often point to RF interference or roaming, not hardware failure.
Worked example / rule of thumb
Rule of thumb: follow the path - physical → VLAN → IP → application. Example: a client cannot reach the internet. Check link up and PoE, confirm the port is in the right VLAN, confirm the client received a DHCP address in the correct subnet, then verify the default gateway and DNS. If the client associates to Wi-Fi but has no IP, suspect VLAN/DHCP before RF.