Native VLAN mismatch detected on interface

[mmarie]

Hello 

I have Cisco CBS350 switch connected to Cisco router C1128, just noticed the below error from the switch 

 %CDP-W-NATIVE_VLAN_MISMATCH: Native VLAN mismatch detected on interface gi1/0/1.

I tried to run the command: "show cdp neighbors gi1/0/1 secondary" and see that VLAN-ID is 0 while the switch VLAN is 425.

Holdtime: 160
Capabilities: Router Switch IGMP
VLAN-ID: 0

So how to solve it.

Appreciate your help 

Thanks
 

[Richard Pidcock]

You need to match the native vlan on each side of the connection.  Not exactly sure of the CLI commands on the CBS350 as I haven't worked with them much, but standard router and switch configurations would look similar to this below:

Router:
!
int Gix/x
 encapsulation dot1Q xxx native (where xxx is your vlan number)
!

Switch
!
int Gi1/0/1
 switchport trunk native vlan xxx (where xxx is your vlan number)
 switchport mode trunk
!

HTH,

Richard

[Blue_Bird]

Hello mmarie ,

Native vlan must match both router and switch...

Router

interface Gigx/x

encapsulation dot1q vlan_id native

Please go through the following link...that may helps you change native vlan on  Cisco CBS350 switch:

https://www.youtube.com/watch?v=wIqBfc5k8kY

Best regards
******* If This Helps, Please Rate *******

[mmarie]

Thank you @Richard Pidcock  & @Blue_Bird 

Here is the current configuration, the router port GigabitEthernet0/1/2 connected to port switch GigabitEthernet1/0/1

Router: sh ip int br

Interface              IP-Address      OK? Method Status                Protocol

GigabitEthernet0/0/0   unassigned      YES NVRAM  up                    up     

Gi0/0/0.425            172.18.158.85   YES NVRAM  up                    up     

GigabitEthernet0/1/0   unassigned      YES unset  down                  down   

GigabitEthernet0/1/1   unassigned      YES unset  down                  down   

GigabitEthernet0/1/2   unassigned      YES unset  up                    up     

GigabitEthernet0/1/3   unassigned      YES unset  down                  down   

GigabitEthernet0/1/4   unassigned      YES unset  down                  down   

GigabitEthernet0/1/5   unassigned      YES unset  down                  down   

GigabitEthernet0/1/6   unassigned      YES unset  down                  down   

GigabitEthernet0/1/7   unassigned      YES unset  down                  down   

Router# sh run int GigabitEthernet0/1/2

Building configuration...

Current configuration : 38 bytes

!

interface GigabitEthernet0/1/2

end

Router# sh run int Gi0/0/0.425 

Building configuration...

Current configuration : 109 bytes

!

interface GigabitEthernet0/0/0.425

encapsulation dot1Q 425

ip address 172.18.158.85 255.255.255.252

end

Switch: show running-config interface gi1/0/1

interface GigabitEthernet1/0/1
switchport mode trunk
switchport trunk native vlan 425
switchport trunk allowed vlan 425

But still get the "Native VLAN mismatch detected" message

Thanks

[Richard Pidcock]

On your router add the native keyword onto your encapsulation statement.

Router# sh run int Gi0/0/0.425 

Building configuration...

Current configuration : 109 bytes

!

interface GigabitEthernet0/0/0.425

encapsulation dot1Q 425 native

ip address 172.18.158.85 255.255.255.252

end

[mmarie]

Thank you @Richard Pidcock 

if adding native keyword to encapsulation statement that will impact any traffic as its for ISP.

Also if i ignore the mismatch error that will cause any issue.

Thank you again

[Richard Pidcock]

There will likely be a small hiccup when you add the native keyword as the interface will likely bounce.  However, this shouldn't be ignored as a native vlan mismatch is definitely going to give you problems.

[Georg Pauwen]

Who is your ISP ? What country are you in ?