VTP over wireless bridge

[salamislimy]

HI

We have switches connected over a wireless bridge, however VTP information is not sent across correctly.

I have seen old community posts with older models, wondering if there is any official Cisco document suggesting that VTP will or will not work across a wireless bridge.

Setup 

9300 L switch running VTP mode client ,VTP version 3 , is connected over wireless bridge consisting of C9124AXD-Z APs ( 9800 controller) to C3560CX-8PC-S switch also running VTP mode client

9300 L switch 

#show vtp status
VTP Version capable : 1 to 3
VTP version running : 3
VTP Pruning Mode : Disabled (Operationally Disabled)
VTP Traps Generation : Disabled

Feature VLAN:
--------------
VTP Operating Mode : Client
Number of existing VLANs : 30
Number of existing extended VLANs : 0
Maximum VLANs supported locally : 4096
Configuration Revision : 1

C3560CX

#show vtp status
VTP Version capable : 1 to 3
VTP version running : 3
VTP Pruning Mode : Disabled
VTP Traps Generation : Disabled

Feature VLAN:
--------------
VTP Operating Mode : Client
Number of existing VLANs : 18
Number of existing extended VLANs : 0
Maximum VLANs supported locally : 1005
Configuration Revision : 0
Primary ID : 0000.0000.0000

[Flavio Miranda]

@salamislimy 

Why both switch are client?

Switches in VTP client mode receive VLAN information from VTP servers and synchronize their VLAN database accordingly. However, they cannot create, modify, or delete VLANs

[salamislimy]

VTP server is the core switch, hope this diagram helps

[MHM Cisco World]

the VTP use native VLAN in trunk link ONLY 
I think the wireless bridge is not trunk 

MHM

[Flavio Miranda]

There is a bug, I bit old this is true, but it says that when the VTP is over bridge is must use Vlan 1 as native.

https://quickview.cloudapps.cisco.com/quickview/bug/CSCeg12593

As you are using a 3560 in one of the sides, this could apply

[salamislimy]

I did see this, but it said it was fixed in a later version, so expected that this will be fixed by now

[Flavio Miranda]

But, do you have at least one vlan in native state for this trunk? Even though cisco remove the limitation for vlan1, I believe you must have some vlan in native state in both sides

[salamislimy]

yes we do have a native vlan on both ends

[Flavio Miranda]

I would recommend you to capture the traffic send towards the bridge with wireshark so that you can check to see if the VTP is even being sent to the air. 

 you can use port span on the 9300 or 3560 and you can easily see this. 

[srimal99]

Have you enable vlan over the links or are those in  trunk mode ?

[salamislimy]

Hi @srimal99 

Its all trunk

[srimal99]

As @Flavio Miranda mentioned you can do packet capture on Wireshark to see traffic reaching Cisco 3560. I had similar issues where bridge connecting  port goes in to error disable state in the switch . Enabled "spanning-tree BPDU filter enable" in the port level and issue resolved.