STP issue on SG220-26

[Rodrigo Vianna]

Hi, I'm having trouble with this model on a few sites, this switches just block and put ports on a "Discarding" mode with no explanation at all and no looping or broadcast storm.

This switches came with firm 1.1.4.8 and is now updated to 1.2.1.5.

Another problem is that all of them stop responding to ping, what generates lots of alarms on zabbix monitoring history, the gone offline for about 20 to 60 seconds and get back online, but in this case, no equipment conected to them turn offline.

The real problem is the STP, on RSTP mode that turno trunk ports to Discarding shutting down a whole link for no visible reason on logs.

Can anyone help on this please?

[marce1000]

             - Do you have logging  entries from the switch , concerning this problem ?

 M.

[Rodrigo Vianna]

Hi, yes, on the swith that is blocking a port trough STP, I got only this log for example:

GigabitEthernet1 STP port state is set to Blocking

GigabitEthernet1 STP port state is set to Learning

GigabitEthernet1 STP port state is set to Blocking

GigabitEthernet1 STP port state is set to Learning

GigabitEthernet1 STP port state is set to Blocking

GigabitEthernet1 STP port state is set to Learning

But in the other side, I got no log at all indicating where the problem might be, but if I reset the switch, then it come back online.

[marce1000]

   - Could 'only' be a cabling or link issue , check port counters, e.g. Then the messages are only related to STP converging again.

 M.

[Rodrigo Vianna]

What errors on the ports could cause this?

The problem occours on all links and all manageble switches on this network are cisco SG220 except for some generic Dlink unmanageble.

The problems are intermitent, sometimes it happens twice in a week, some times once per month.

Switches blocked trough STP never show anylogs that might explain the problem.

Also, I got about 4 shopping centers with the same problem, different location, different network, but all using this model bought at the same time, the others shopping centers that uses SG300, SG350, Catalyst 3560/2960, HPs, dont have any problem like this..

[marce1000]

                                                         >....What errors on the ports could cause this?

               - I am still suspecting 'cabling' and or problems related to 'good connectivity'  between the involved  devices and or particular network(s)

 M.

[Rodrigo Vianna]

OK, Marce, but give me a call, what errors or problems could cause this symptoms??

And how all the links on different locations and networks have the same problem, but only the ones using SG220 series..

[marce1000]

                                           >...but only the ones using SG220 series..

 - That is a very valid business concern, but note that this is a volunteering forum-only. You may want to engage Cisco :

                       https://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html

 M.