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I have around 40 L2 switches IOS v12.0-12.2 (2960, 3560, 3500, 3750) running in VTP client mode and one L3 switch CatOS v6.3(5) (6500) running in VTP server mode, all connected together. I would like to switch everything in VTP transparent mode without any interruption of service.

I've already test on a poc version with 3 switches (Catalyst 2950, 3560 and 3750). Using serial and SSH connection, it is seems working but i'm not sure it is enough representative compare to the real network.

Knowing that the VTP Pruning is enabled, I am wondering what would be the best procedure to proceed the changement. I've read that we could lost connection by keeping it enabled.

  • Should I change the server or clients first?
  • Is it important to change the VTP domain and VTP Pruning parameters?
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What is your motivation here? Why the change? – cstamas Oct 19 '12 at 10:14
I need to change VTP to prepare an upgrade. I don't think this info will help to answer my questions. – J. Smith Oct 19 '12 at 11:13

Moving to transparent mode is a good thing. The transition is a pain, but ultimately you'll end up with a lot less risk.

Change the clients to transparent first. Once in transparent mode confirm absolutely that the expected list of VLAN's remains (wait 5 minutes or so). I'd go so far as to suggest copying the VLAN definitions into a buffer to re-paste if necessary. Make sure the configuration is written to NVRAM!!

Even running in transparent the VTP domains need to match. Don't change it.

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Thank you rnxrx. I've checked, and my vlan databases are mostly written on the FLASH memory. Why should I make sure it is written to NVRAM instead ? – J. Smith Oct 22 '12 at 10:07
On that post, people had an issue by changing clients first. . I also used VTP Pruning mode, shoud I desactivate it before ? – J. Smith Oct 22 '12 at 10:08

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