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VTP question

Hi seniors, Please guide me on vtp in switching.

Some texts says "if you add a switch with higer revision number in switched network, it will not update its revision number and so vlan.dat will be same in either case(server or client)

and some text says "if you add a switch with higher revision number in switched environment, all other switch will update their database according to newely added switch. I am bit confused on this topic.if second is the case, then how one can add a switch in network... Please guide. Tahir.


Re: VTP question

Hi Tahir,

When you add a switch to a network with a higher revision number, of course, it will not update its OWN database and revision number.

It will update the vlan database and revision number of OTHER switches in the network that have a lower revision number.

When the other switches see VTP advertisements with a higher revision number, they will accept it and update their own vlan database and revision number.

Provided, they are in server or client mode, vtp domain name and password are the same.




Re: VTP question

Actually when the revision number of higher switch which is working in server mode will send the vtp updates to all and when find the higher revision number of itself, it will send the vlan database to all the switches and after a movement you come to check that all the switches in the domain has the same revision number and same vlan database.For this alll the switches need to be in same domain.



Re: VTP question

Hi Tahir,

To answer the part of how to add a new switch to your network, you need to reset the revision number of the newly added switch before adding it to your network by either changing the domain name to a bogus name then back to the original name, or via configuring the switch as transparent then as server/client again. This way you'll make sure that the newly added switch is updated with the current running network VTP information rather than corrupting it.


Mohammed Mahmoud.

Re: VTP question


The proper way of adding a new switch to a VTP domain is to set this switch VTP mode to TRANSPARENT before connecting it to the VTP domain.

Take the following precaution as well

- Set a PASSWORD to your VTP domain

- Configure all switch ports not connected to another switch to stop BPDU

Take note that switches VTP mode by default is SERVER. Some newly purchase device has been use in a LAB from its source.



Community Member

Re: VTP question

Thanks to all seniors who guided me on the said topic.



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