Controller Based WLANs

Why A7220 controller started to crash/reboot when the uplink port was connected to a 100 Mbps?

When auto-negotiation is enabled on 7220 port and not on the Cisco port, the 7220 port will auto-negotiate to 100Mbps Half-duplex as per the Ethernet standard.

In such configuration, a high TX traffic can cause back pressure on Ingress resulting in the system reboot. If you force the speed on 7220 port to 100Mbps Full-duplex, then both ends will operate in Full-duplex mode and you may not see the issue.