[c-nsp] Question about setting up VTP

[Jon Lewis]

On Sun, 1 May 2005, Jeff Crowe wrote:

> The switches are in production environments, so each has vlan's already
> setup on them.  Luckly, the only common vlan between the two is vlan 1
> (management) which is also on the same subnet on both switches, all the
> other vlans are unique.  I am planning on using dot1q for encapsulation and
> have set the said's accordingly.
>
> If I enable the port 3/1 to start passing vtp information, will one switch
> overwrite the other's vlan database?  If so, how can I prevent this from
> happening?

I suspect so.  I've never enabled VTP after the fact, but I'd think the
way to go is pick one of your switches and think of it for the moment as
the "VTP master".  Define all the vlans you want in the VTP domain on that
switch, making sure it ends up with a suitably high VTP configuration
revision.  The switch with the highest VTP confrev "wins", so if you
enable VTP on the master first, make sure it's got all your vlans defined,
and has the highest confrev, as you add additional switches to the VTP
domain, they should take the VTP config from the "master".

Obviously, make sure you have backups of all your configs and the ability
to quickly restore them if things go badly.

----------------------------------------------------------------------
 Jon Lewis                   |  I route
 Senior Network Engineer     |  therefore you are
 Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________