Hi
I have a switch only configured with VLANs at Layer 2 th trunked upto a L3 switch. There are multiple VLANs configured but last week we had a problem and all that was in the error log was the instance of two VLANs going down then back up. As below .... (Dates wrong I know)
*Jul 12 08:43:58: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan36, changed state to down
*Jul 12 08:44:14: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan9, changed state to down
*Jul 12 08:44:18: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan9, changed state to up
*Jul 12 08:44:18: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan36, changed state to up
My understanding is that for a VLAN to go down in this way then all its associated active interfaces have to go down also, or spanning tree intervenes. In this instance there were no other errors in the log showing any ports flaps etc and these VLANs aren't associated with any Spanning Tree instances.
It may be a schoolboy oversight or error, but if anyone could give me a viable explanation for this to happen in this way I would be grateful.
Many thanks in advance.
