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12916 undicast flooding?


12916 undicast flooding?


in the last 2 weeks i have a problem ...


i capturing sflow on uplink in access switch and i seeing unicast massages that soure ip and destention ip not mach to the uplink on the same access switch...

i check in anthoer switche's and i found this packets is too showes , (my sflow is on the uplink in the acces switch and not in the back bonde switch)


in some sites i check this case and i see "unicast flooding " and i dont sure it is my problem 


can some one advise my how to check the root of the problem


Re: 12916 undicast flooding?

Hi @kobi_Levi921 !

Yes, this looks like a unknown unicast flood indeed, but it is something that may happen for a short period of time when your network is running MSTP or RSTP and there are topology changes. When a switch gets a topology change and it is running MSTP/RSTP it will flush the MAC table immediately (unlike legacy STP) which leads to very short unicast floods until MAC tables converge. Check if that is not the case. Of course, in this case amount of such flood will be pretty small. 

Hope this helps!


I am an HPE employee

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