According to the FortiOS 7.6 Study Guide and the FortiSwitch 7.6 FortiLink Guide , the health and stability of the control plane between a FortiGate and a managed FortiSwitch are maintained through a continuous keepalive mechanism. Once a FortiSwitch is authorized and transitions to the FL_STATE_READY state (as shown in the debug output in the exhibit), the devices must ensure the management tunnel remains active.

The primary mechanism for this is the FortiLink heartbeat . The documentation specifies that a managed FortiSwitch sends heartbeat messages to the FortiGate every few seconds over the FortiLink interface. The FortiGate, acting as the controller, must acknowledge these heartbeats to confirm that the switch is still reachable and responding to management commands. If the FortiGate fails to receive a certain number of consecutive heartbeats, it will consider the switch "offline" in the GUI, even if physical link lights remain green.

Checking for these heartbeat exchanges is a critical troubleshooting step to verify that the CAPWAP (Control and Provisioning of Wireless Access Points) based management tunnel is functioning correctly without intermittent drops. Option A is incorrect as port disabling is a configuration choice, not a health check. Option C is incorrect because firmware updates are manual or scheduled, not automatic upon authorization. Option D is a logging function that relies on a healthy management tunnel but is not a direct measure of the FortiLink's operational health.

To enable SNMP v2c on a managed FortiSwitch, the essential requirement involves configuring the SNMP agent and community strings:

Configure SNMP Agent and Communities (D):

SNMP Agent: Activating the SNMP agent on FortiSwitch allows it to respond to SNMP requests.

Community Strings: SNMP v2c uses community strings for authentication. These strings function as passwords to grant read-only or read-write access to the SNMP data.

Understanding Other Options:

Create an SNMP user (A) is necessary for SNMP v3, not v2c, as it involves user-based authentication and encryption.

Specify an SNMP host (B) is typically a part of SNMP configuration but not a requirement just to enable SNMP.

Enable SNMP v3 (C) is not related to enabling SNMP v2c.