Vlan configuration

Unanswered Question
Nov 19th, 2008

Hi, I have two switches one is 3750G and another is 2960G interconnected through 2 etherchannels. C3750G is configured in VTP Server Mode and 2960 is configured in VTP Client mode, Now I would like to add a new vlan in the Network, I am able to configure in 3750 as its in Server and cannot in 2960 as it is in Client mode. So to configure the vlan in 2960 can I change the VTP mode from clinet to Transparent and configure the vlan then again change to transparent to client mode. is there any risk to change the vtp/vlan database or any configuration? Please anyone suggest me.

I have this problem too.
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Davy Ad Thu, 11/20/2008 - 00:20

Hi Goutam ,

No risk , but you don't need to do that if you configure it on the server it will take it automaticaly that is why you don't have to do it again in Client.



goutam_04 Thu, 11/20/2008 - 01:39

yes, existing vlan is showing in 2960,


Do you mean that, If I configured the vlan in Server no need to configure the vlan in client, then how do I allowed in the trunk port on 2960 side.

I have already configured the vlan in server but its not showing in client.

Davy Ad Thu, 11/20/2008 - 01:49

Pleas try to check if the domain name are the same and the 2960 is in client mode . After that delete existing Vlan database in the Switch 2960 . then it should be working.

use "show flash" to ses the existing vlan databas e.g (416 -rwx 556july08 2008 15:05: 21+00:00 vlan.dat.renamed) <- You will need to remove this first and then reload.



goutam_04 Thu, 11/20/2008 - 01:59

yes vtp domain is same. no actually I cannot effect the existing service. the switch is in connected in the network.

Davy Ad Thu, 11/20/2008 - 02:56

okay , is there any VTP password , if not try to do what i said when the switch is not connected to life Network

glen.grant Thu, 11/20/2008 - 04:37

If you create the layer 2 vlan in the 3750 which is the server then it should show in the 2960 with the "show vlan command . This is different than if it is allowed across a trunk .If you have manually pruned your connecting links then on both sides on your connecting link interfaces you would have to add "switchport trunk allowed vlan add XX ,where XX is the new vlan you created on the vtp server. To check to see if vtp itself is working correctly then on both switches issue the "show vtp status" command and look at the config revision number they should be exactly the same , if not then vtp is not working or configured correctly.


Check in 2960G side if you can able to see already existing Vlans created in 3750G .This will ensure that etherchannel is working between 2 switches and If you can't see any Vlan's in 2960G side, check ether channel config between 2 switches and VTP server name configured (case sensitive) in client side.




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