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New Member

Native Vlan mismatch

hi ,

Can any one let me know when does Native Vlan mis match issue occurs .

any help on this would be appreciated.

Thanks,

Akber.

6 REPLIES

Re: Native Vlan mismatch

you will have the mismatch whenever you have configured dot1q trunks and have different native vlans on either side of the trunk.

http://www.cisco.com/warp/public/473/176.html#subtopic1a

HTH

Narayan

New Member

Re: Native Vlan mismatch

Hi,

cr1-hy:-

interface GigabitEthernet3/5

description cs103-hy ge1/1

switchport

switchport access vlan 999

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 14,485

no ip address

logging event spanning-tree status

logging event bundle-status

logging event trunk-status

load-interval 30

storm-control broadcast level 0.35

end

=================================

#module 1 : 2-port 1000BaseX Supervisor

set vlan 999 1/1-2

set port disable 1/2

set port name 1/1 To-cr1-hy-gi3/5

set udld aggressive-mode enable 1/1

clear trunk 1/1 1-13,15-484,486-1005,1025-4094

set trunk 1/1 desirable dot1q 14,485,1006-1024

set trunk 1/2 off negotiate 1-4094

set spantree portfast 1/1-2 disable

set port lacp-channel 1/1-2 mode off

===========================================

based on the above config we are seeing the below error .

%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet3/5 (1), with SMC0934007Z(cs103-hy2) 1/1 (999).

Please let us know why are we getting this error on cr1-hy

Thanks,

Akber.

Purple

Re: Native Vlan mismatch

I know on older switches like the 2924's you would get this message on the distribution boxes even when the link is not a trunk, in that case it is just a informational message and doesn't hurt anything.

New Member

Re: Native Vlan mismatch

Hi,

cr1-hy:-

interface GigabitEthernet3/5

description cs103-hy ge1/1

switchport

switchport access vlan 999

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 14,485

no ip address

logging event spanning-tree status

logging event bundle-status

logging event trunk-status

load-interval 30

storm-control broadcast level 0.35

end

=================================

#module 1 : 2-port 1000BaseX Supervisor

set vlan 999 1/1-2

set port disable 1/2

set port name 1/1 To-cr1-hy-gi3/5

set udld aggressive-mode enable 1/1

clear trunk 1/1 1-13,15-484,486-1005,1025-4094

set trunk 1/1 desirable dot1q 14,485,1006-1024

set trunk 1/2 off negotiate 1-4094

set spantree portfast 1/1-2 disable

set port lacp-channel 1/1-2 mode off

===========================================

based on the above config we are seeing the below error .

%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet3/5 (1), with SMC0934007Z(cs103-hy2) 1/1 (999).

Please let us know why are we getting this error on cr1-hy

Thanks,

Akber.

Cisco Employee

Re: Native Vlan mismatch

Hi Akber,

From your cr1-hy can you post the output of "sh interface gig3/5 switchport" I believe it will show you native vlan as 1 and your switch running CATOS has native vlan 999 and that is the reason it is showing native vlan mismatch.

On CATOS switch when you configure "set vlan 999 1/1-2" as you see in your config , this will make vlan 999 as native on port 1/1 which is also a trunk port and IOS switch you have not defined any native vlan and is the reason default is vlan 1 on trunk ports and therefore you see native vlan mismatch.

HTH

Ankur

*Pls rate all helpfull post

Purple

Re: Native Vlan mismatch

Ankhasi is correct , the IOS side is native vlan 1 because you did not set it as anything else so the default is 1 . On the catos side the native vlan is whatever vlan you set the port into which is 999 in your case thus the mismatch , to correct on the IOS side add "switchport trunk native vlan 999" .

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