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New Member

VTP Database

I am trying to figure out what would happen in the following scenario:

I have two switches stacks on my network, one (Switch stack A) in a VTP domain with VLANs and one (Switch stack B) not in a VTP domain and all ports and traffic in VLAN1. These two switch stacks have a trunk between that allows them to pass traffic back and forth between the two.

If I change the mode of switch stack B from server to client and then join it to the domain on Switch stack A, will they still be able to communicate and the network operate as it had been before?

I believe it will since all traffic on Switch stack B is in VLAN1, B will receive the VTP database with all the VLAN information and I should then be able to assign ports on B to various VLANs.

VIP Purple

Re: VTP Database


you are exactly right: by changing your Switch B to VTP client mode and adding it to the same VTP domain (be careful, the VTP domain name is case-sensitive), Switch B will receive all the VLAN information from Switch A, and you will be able to assign ports to VLANs that are accessible from both switches.



New Member

Re: VTP Database

I agree with GP.

A point to also note...

If switch B has been configured for vtp before, it may have a configuration revision number greater than zero.

If the configuration revision of the switch you inserted was higher than the configuration revision of the VTP domain, your recently introduced switch, with almost no configured VLANs, may erase all

VLANs through the VTP domain.

This happens whether the switch is a VTP client or a VTP server. A VTP client can erase VLAN information

on a VTP server. You can tell that this has happened when many of the ports in your network go into inactive state but continue to be assigned to a nonexistent VLAN.

Always make sure that the configuration revision of all switches that you insert into the VTP domain is lower than the configuration revision of the switches that are already in the VTP domain.

To check the config revision type "show vtp domain"


Re: VTP Database


In addition to Sarb's post above, please use the following steps to make the VTP clinet's revision number zero before introducing it to the VTP domain:

1. Change the VTP mode to transparent and then back to server, this will bring the revision number to zero.

2. Gave a bogus VTP domain name to the client and change it back to the domain name it is about to join.


-amit singh

New Member

Re: VTP Database

Thanks all for your help and insight.

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