Troubleshooting Tip: FortiAP reboots constantly (PoE not being negotiated correctly by Cisco Switch)

[laltuzar]

Description

This article describes troubleshooting steps to fix issues where FortiAP 431F does not power on correctly when connected to a Cisco Switch.

Scope

FortiAP 431F or any AT PoE FortiAP.

Solution

1. Ensure that LLDP is enabled on Cisco switch so it can correctly negotiate the PoE.
2. Configure FortiAP PoE mode to 802.3at static on the FortiAP CLI:

cfg -a POE_MODE=2
cfg -c
[0(Auto detect), 1(802.3af), 2(802.3at), 3(Power adapter only), 4(Controlled by AC), 5(full), 6(high), 7(low)]. default=0

3. Configure the Cisco switch with a fixed PoE supply, then restart the physical interface:

power inline static max 26000 (26000 miliWatts = 26 Watts.)

IMPORTANT: Please note that this last configuration is a last-resort configuration and must be reviewed with Cisco support first. It will enable the switch to always provide 26000 Watts despite any device connected to the port, which might burn out devices that cannot handle this amount of power. PoE negotitated by LLDP should always be preferred.

Related articles:

• 802.3at vs 802.3af: Which PoE Standard to Use.
• Useful Tips for Selecting PoE Cables.