[c-nsp] Splitting VTP domain without a meltdown

Michael K. Smith - Adhost mksmith at adhost.com
Sun Oct 7 11:49:01 EDT 2007

Hello Jeff:

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net on behalf of Jeff Kell
Sent: Fri 10/5/2007 10:05 AM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] Splitting VTP domain without a meltdown
I'm trying to split a branch building off of the main campus VTP domain and not having much success.

Currently we have one VTP domain that propagates over the main campus.  The goal is to split this into several independent domains to reduce the vlan count and move to L3 distribution, and make the L3 uplink point a VTP server for the new domain.

In a testbed case, I could remove a switch from the domain.  The vlan configuration remained "frozen" and things kept working OK.

In the production case, when I change the VTP domain, the trunks drop back to vlan1 only and things go to hell :-)

Is there a "non-invasive" way to break a building off of a VTP domain without visiting each wiring closet and manually configuring things for the new domain?  Surely there is a "non-forklift" approach to accomplish this task.

Thanks in advance,


I'm assuming the switch you want to pull out of the domain is a CLIENT to a server somewhere.  In that case, I would recommend announcing a maintenance window, disconnect the switch from the network, flip the VTP to either TRANSPARENT or whatever new domain you want to use, then cut-and-copy in your VLAN list via a console connection.  The only time I've ever seen a non-invasive technique work is on old Cat OS switches.  All of the IOS switches seem to have issues with this event, so I've found it easier in the long run to just take the hit and do it in one shot.



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