Hello @Carlos_Fandango
According to the log snippets the disconnection of the ports was shorter than 30 seconds, probably 30 seconds is the disconnection the end user experienced.
You see in the log messages indicating that port was blocked by AAA and by STP. This can lead to wrong conclusion that this protocols are blocking the port. In my opinion this is not true. The port is going down and then after a couple of seconds again up. When the port goes up it is blocked for another 3 of seconds by STP which need to check if BPDUs are received and what the port role in the STP topology should be. The port is also blocked by AAA in this case 802.1x which needs to perform an EAPOL exchange every time the port goes up in order to authenticate the user/machine.
So this procols add a couple of seconds to the offline time. In the spanning-tree configuration you can configure the port as admin-edge-port as explained here. This should reduce the duration of the disconnection.
Regarding 802.1x I am not sure that there is any option to reduce the time AAA is blocking the port, it probably also depends on the EAP method you are using.
Based on the log it is not possible to say what causes the disconnections in the first place. This could be physical issues. You can use the command show interface <int-nr> to check the statistics of the port. Pay attention to the section Errors (since boot or last clear). Feel free to paste the output here if necessary.
Use show interface brief <port-nr> to check the mode of the port, is it operating with 1000FDx, 100FDx, 100HDx. HDx or half duplex mode shouldnt be expected for todays devices so this may indicate duplex mismatch with the connected end-device. In this case you should make sure that you have exactly the same speed and duplex settings on the switch port and end device.
If you see the issue always on the same couple of ports and there are FCS or allignment errors there, you probably have HW issues. You should perform cross-testing in order to determine what component of the connection causes the disconnection. First you can replace the cable. Then you can swap the port of this device with a port of a known working end- device which doesnt have such disconnections. If the issue moves with the end device, the it is either cable , patch pannel or client NIC. If the issue stays with the port and all other components were replaced with known good and working ones, then it could be a problem with the port. You should check for errors, speed-duplex mode, check if your switch is running a current firmware version and update if it is not. If your cross-tests are showing clearly that the issue stays with the port and nothing of this helps you should contact the support for more troubleshooting.
Hello,
Please provide feedback if my post has answered your question and was helpful in troubleshooting the disconnections! If so, mark it as resolved. If not feel free to share any new findings.