VLAN config replaced.

Unanswered Question
Dec 11th, 2008

Hi, suddenly I have observed that vlan configuration of one access switch has been replaced with one distribution switch configuration. I have checked all the possibilities but there is no reason to change. Can you suggest me how do i know the reason due to that it has been replaced.

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Overall Rating: 5 (1 ratings)
lejoe.thomas Fri, 12/12/2008 - 02:43

Hi Goutam,

It sounds like a higher VTP revision number replacing a lower one. Probably having a look at show vtp status message on the access-switch, will indicate when configuration was modified and if so the source address as well.



goutam_04 Fri, 12/12/2008 - 02:51

yes..i have seen everything..it was showing higher revison no. but i want to know how did it happen, because spanning tree bridge priority was given to high no and low no. is configured in distribution switch to make the switch as root.... so it cannot be root bridge. So I want troubleshoot how it came to higher revision no.

solpandor Fri, 12/12/2008 - 03:45


my understanding is that if you plug a switch in with a higher revsion no it will replace the revision no on all the switches within the VTP domain.

what should be done is the change the switch with the higher rev no from server to Transparent (to clear the rev no) and then back to either server or client and then plug it in.

Experts please correct if im wrong.


lejoe.thomas Fri, 12/12/2008 - 04:04

Hi Goutam,

VTP revision numbers are not related to spanning-tree root bridge selection. VTP revision numbers (increase), whenever a vlan is added or deleted etc on switch configured as vtp server, which propagates this to all other switches (vtp server and client) within the management domain (vtp domain).

By issuing show vtp status on the access switch, you'd be able to be see when the configuration revision incremented. Once you have this information, you could check whether anything particular happened during that time period, such as details gathered from syslog or logging information from switches configured in vtp server mode.




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