How to block port where a HUB is connected and containing a loop without Hight CPU impact ?

Hi Everybody

I try to block a port where i connect a HUB containing a loop on a 6560.

I have impleted bdpu protection with next command :

qos trust-ports no user-port filter user-port shutdown bpdu policy port group UserPorts 1/1/1-5 qos apply

The port is really disable

SW-B1-1 # show qos log 8/03/22 9:41:59 [@00:23:54]Qos violation in port:1/1/1 BPDU packet UserPort shutdown MAC 94:24:E1:12:34:56 -> 01:80:C2:00:00:00 8/03/22 9:41:59 svlan 51 port 1/1/1 default 8/03/22 9:41:59 MAC 94:24:E1:12:34:56 -> 01:80:C2:00:00:00

But my probleme is CPU usage of 6560 is to 100% and so the network is not available for users connected to the switch


Probably the feature that you are looking for is loopback detection. It's explained in the manual.