[c-nsp] VTP doubt

Patrick M. Hausen hausen at punkt.de
Thu Jun 16 13:25:15 EDT 2016


> Am 16.06.2016 um 18:52 schrieb james list <jameslist72 at gmail.com>:
> Hi
> I've two 6500 (6500-A and 6500-B) in production as VTP server, access
> switch are 3750 or 4500 as VTP clients.
> Today if I add manually a vlan on one of the two VTP server (ie on 6500-A)
> it's propagated to the other server (6500-B) and clients.
> The question is: do I've to add manually on both VTP servers or just one is
> enough to keep redundancy ?

Only one. If both C6500 are in server mode they will synchronize and save the
VTP data. You can check the status like this:

Core1#sh vtp status
VTP Version                     : 3 (capable)
Configuration Revision          : 199
Maximum VLANs supported locally : 1005
Number of existing VLANs        : 55
VTP Operating Mode              : Server

If the configuration revision on both servers is the same, they are in sync.
It doesn't matter on which you add the new VLAN.

> If VTP server (6500-A) is broken down for any reason, does 6500-B still
> know the vlan added before only on 6500-B and continue to propagate to
> clients ?

Yes, it will.

A popular way to shoot yourself in the foot is to bring a new system into your
VTP domain that has been used before and has got:

* VTP server mode enabled
* VTP data with a revision higher than your exisiting equipment

Plug in for instant fun :-) Been there, ...

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