modification of VTP mode

[TECH-JEFF]

Hi, if I changed the VTP mode from server to transparent, so that I can create a VLAN ID, will the distribution switches go down which is connected to a Cisco 3750 L3 switch?

Thanks

Jeff

[Milos Megis]

Hi,
I am not sure if I understand you correctly. Could you please provide some topology diagram.

However when you put switch to transparent mode, there is no consequence on other switches.
Switch in transparent mode will forward VTP frames but will not learn from them.

On other side if you create new VLAN on switch in transparent mode then you must have this VLAN defined on all switches where you want to transfer frames for that VLAN.
Switch without defined VLAN (and of course allowed on trunk ports) will not forward traffic for that VLAN.

[TECH-JEFF]

It's like this, the current config of the Cisco 3750 L3 switch is set to Server mode. I tried to type the command

show vtp status and it show server mode

I tried to create a test vlan and showed me 

vtp vlan cannot be configured .....

So what I did was set to transparent mode, created the vlan successfully and switched it back to server mode. The reason why I switched it back to server mode after the creation of the new test vlan is because I suddenly heard from one of the cubicles that the internet just stopped working :)

Thanks

Jeff

[Milos Megis]

VLAN IDs 1006 or above can be configured only in transparent mode if you have VTP version 1 or 2.

In VTP version 3 you can configure them in any VTP mode.

But why your internet stopped work, I don´t know. If you have some "window" for tests then you can try put it into transparent mode and look if some VLAN disappeared from config or something like that.
I don´t know say what could happen.

[TECH-JEFF]

@Joseph Doherty

The VTP version is 3

@gpauwen

The reason for creating a new vlan is for a test purpose, for another project

@Milos

I really don't know what happened. When I changed the VTP mode to transparent, I saw a series of VLAN's showing after the command line:

vlan internal allocation policy ascending

VLAN10

access

VLAN20

access

and so on so forth. I may have to learn more about VTP's and its use but thanks guys for the inputs, appreciate the effort to comment in. Still a long journey in learning Cisco

Thanks

Jeff

[Georg Pauwen]

Jeff,

in VTP version 3 the default status for a switch is secondary server mode. Try and change your switch to primary server mode first before creating the Vlan:

3750# vtp primary vlan

[Joseph W. Doherty]

I haven't worked with VTP v3, but I recall it's very particular about server/client relationships.  If you took the server out of the domain, that might have been the cause of your access problems.

[Georg Pauwen]

Hello,

on a side note, what exactly are you typing to create the Vlan on the VTP server switch ?

[Joseph W. Doherty]

Assuming we're dealing with VTP version 1 or 2, when you switched from to transparent to server mode, the revision number should have been reset, and then that device's VLAN information overridden by any neighbor VTP device, in server or client mode, with a higher revision number (and in same domain).