VTP Question

Hi all,

doing some of the nuggets with the lovely Jeremy, and he said something that confused me..

he was demonstrating, what happens when you introduce a switch to a network that has a higher revision number than the existing vlan set up, and its possible that all the switches in the vtp domain will update themselves as the revision number is higher.. which I get totally..

he then said , to reverse the damage, you could just configure one of the switches to put back the correct vlan data and it will then replicate to all switches, which again im fine with..

but, he said once a switch with a higher number replicates its vlan info, the other switches delete / replace there own vlan.dat with this new info.. but surely you would have to go onto all the switches in the network and re-add the ports? for example if the switches were all part of vlan 10, 20 and 30 and switch C had 3 ports on vlan 30 for three PC`s.. this vlan info would be lost when the "rogue" switch was added. When the new config is replicated, how does the switch C know which ports it had on van 30, since all the config was lost?

hope you understand what im asking

cheers

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Comments

networker050184

The ports stay assigned to the VLANs due to the config being there. They just go into an inconsistent state while the VLAN does not exist in the database.

websponge

thats what I hoped you would say

so if a rouge switch was added and vtp spread the word! so to speak, the switches would still have ports assigned to the original vlans, but would have no idea whats going on as there are now new vlans in play...

networker050184

Yep. You'd just see a whole bunch of orange lights on your switch and if you look at the CLI I believe it says inconsistent VLAN state.

websponge

networker050184 wrote: »

Yep. You'd just see a whole bunch of orange lights on your switch and if you look at the CLI I believe it says inconsistent VLAN state.

thank you.. appreciated..