Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

VTP Pruning probleme

Hi all,

I have experienced a probleme with VTP pruning (with RSTP).

Before configuring the entire network, i have make a small network disconnected from the other to test pruning.

In the test, all switch learn the vlan and no vlan pass but the one.

Probleme, when i type the command "show interface trunk" on a 2950C (the vtp server is a 3550), i see a vlan number 7. But the 2950C has no "UP" interface in this vlan. Even the 2950C have only one connection (trunk) to the 3550, the vlan 7 is shown with the command "show interface trunk". The result of the command "sh int tru" on the 3550 is OK. I only see the vlan that should cross to the 2950C.

Has someone have an idea of the problem ?


IOS 12.1.22.EA4 on 2950

IOS 12.1.14.EA1a on 3550


Re: VTP Pruning probleme

It doesn't matter if you don't have a port up in the vlan , the show int trunk command just shows what vlans are allowed across the trunk not what vlans are actually up on the box . This is governed by the switchport trunk allowed vlan XX " command that is on the interface . Check the interface on the 2950 and see what is being allowed across on that side . Also make sure the 2950 is indeed setup as client in the network and not a server .

New Member

Re: VTP Pruning probleme


All vlan are allowed to pass through the trunk. And i make the pruning on the VTP to avoid the use of the command "switchport trunk allow vlan X-Z".

also, 2950 are in client mode...

ovt Bronze

Re: VTP Pruning probleme

Does 3550 have access port(s) in vlan 7? If yes, 2950 should be able to send vlan 7 broadcasts to 3550 and vlan 7 shouldn't be pruned from the trunk. Anyway I'd suggest to upgrade both switches.

New Member

Re: VTP Pruning probleme


3550 have only interface trunk and no access port int vlan 7.

anyway, thanks for help

CreatePlease login to create content