VTP Domain Server Change

[mjgoodman]

I have a 5500 with hybrid IOS and I also have a 6509 with Native IOS. The 5500 is currently designated as the SERVER in the VTP domain. My 6509 is transparent and I want to make it the new VTP SERVER. Can anyone tell me what procedure I should use to promote the 6509 and revert the 5500 to transparent? Any caveats?

Thanks in advance,

Mike

[Prashanth Krishnappa · Accepted solution]

As long as the VTP config revision is the same on both the switches, you can change the mode on your 6500. To be safe, you could change VTP mode on your 5500 to be transparent, and then change the 6500 to Server

[milan.kulik]

Hi,

I don't agree this is a safe way.

I'm not sure if a transparent switch cares about VTP config revision number. I don't think so.

And what happens at the time you change 5500 to transparent? Answer: There will be two transparent switches in the network. If there were NO OTHER VTP server or client in the network (I hope there is) or if you changed 6500 to server BEFORE it receives VTP info from the other server or client you'd lose your VLAN database (transparent switch doesn't fill it's VLAN database with info from VTP frames, see http://www.cisco.com/warp/customer/473/21.html#vtp_mode for details).

So MY RECOMMENDATION:

1) Doublecheck the VTP domain names are identical on both switches

2) Check VTP revision number is 0 on 6500 - it should be on transparent switch. If it is not 0, force it 0 by changing VTP domain name to something else and back to the correct value.

3) Change 6500 to VTP client.

4) Wait until 6500 receives correct VLAN information from VTP (you should see VTP revision number changed, VTP last updated by ..., correct VLANS, etc.)

5) Change 6500 to VTP server.

6) Try to make any VLAN change on 6500 (define a new test VLAN, e.g.). Check if this change has been correctly propagated to the network.

7) If everything works OK, you can change 5500 to transparent. (Or you can leave it as a backup VTP server.)

Regards,

Milan

[Prashanth Krishnappa]

VTP Transparent does *NOT* participate in VTP. The VLANs you create are all just*locally* siginificant. A Switch in VTP transparent mode does not generate any VTP updates but only forwards VTP updates it receives.

It is ok to have all your switches in VTP transparent mode. I have seen lot of customers who do not make changes to VLANs use this mode.

[mjgoodman]

Thanks for the info. but I have one other question as well as some clarification. All of my switches in the network are transparent by design. I don't want VLAN's from one switch showing up on another.

That being said, I have the 6500 currently set to transparent but I do have all of the pertinent VLAN's configured already. All I want to do is change the 6500 so that it is the primary VTP switch and eliminate the 5500 altogether.

I read your suggestions which I've taken note of but it leaves me with one question. Does it matter if there are two VTP servers in the LAN? I plan on doing the following:

1. Checking the revision on the 6500 and changing if neccasary.

2. Changing the 5500 to transparent.

3. Changing the 6500 to Server.

Your thoughts?

mike

[Prashanth Krishnappa]

VTP server is useful only in a Server/client topology. If you have all your switches in Transparent mode, why would you want to have couple of switches in VTP Server mode?

Yes, you can have more than one VTP server in a VTP domain

[mjgoodman]

I don't know. If I don't need it then maybe I should just make them all transparent.

Just to clarify again:

I have 2 Core switches, 1 distribution switch, & 9 closet switches for users (access layer). I think my thinking was that the VTP server mode served another purpose other than being the primary VLAN manager. If not, then I guess I can put the 5500 in transparent mode and migrate it off the network from there.

[milan.kulik]

I'm confused now. My understanding was you were using VTP server as the central point of VLAN definition.

And my recommendation was how to migrate it safely from one switch to a new one.

If you are not using VTP in fact (i.e. the only 5500 is server and all other switches are VTP transparent, all VLANs are configured locally) you can change all switches to transparent and don't care about VTP at all.

Regards,

Milan