VTP Transparent

Unanswered Question
Jon Marshall Thu, 12/06/2007 - 03:19

Hi Ali

Transparent mode will save the vlan database between reboots. The vlan database on a transparent switch is local to that switch only ie. a switch in transparent mode will not update it's vlan database when it receives VTP advertisements from another switch nor it will forward out advertisements of it's own database. On a transparent mode switch you can add, modify and delete vlans.

Server mode allows you to add, modify and delete vlans and will propogate these changes out to VTP clients and other VTP servers with a lower configuration revision number.

Clients cannot create or delete vlans. They can only update their database based on VTP advertisements and they do not store a copy of the vlan database between reboots.



Jon Marshall Thu, 12/06/2007 - 03:31

Hi Ali

Assuming you want the new switch to get it's vlans from the existing VTP server.

On the switch you are adding

1) Make it vtp transparent first

ie "vtp mode transparent"

This will set it configuration revision number to 0.

2) Make it a vtp client

ie "vtp mode client"

3) Make sure the VTP domain name matches and that if you have a VTP password set you also set this on your new switch.

4) Connect the switch together via a trunk

The new switch should then synchronise it vlan database from the VTP server.



Kevin Dorrell Thu, 12/06/2007 - 03:31

That's fine, but before you add the new switch, make sure its VTP configuration is less than that of the domain you are adding it to. The whole domain will update to the switch that has the higher configuration revision.

THe easiest way to ensure this is to take the new switch before you add it, and put it in VTP transparent, then back into server or client. That will knock the config revision number down to zero. You can chack it with show vtp status

Kevin Dorrell


Kevin Dorrell Thu, 12/06/2007 - 03:27


Sorry, but can I clarify one point please. The client does keep a local current copy of the database in the vlan.dat file, and will use it on reboot. If you isolate a client and reboot it, it still has the VLANs.

Kevin Dorrell


Jon Marshall Thu, 12/06/2007 - 03:32

Hi Kevin

Thanks for picking that up, i don't like to mislead people on this forum.



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