A problem with NATIVE_VLAN_MISMATCH

[a.m]

Hello,

In the following topology, I was asked to implement the inter-vlan routing on the layer 3 switch MLS.

The activity progress counter shows 100% but I see a vlan mismatch on both of S1 and MLS. I don't understand the reason. 

%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet0/1 (1), with S1 GigabitEthernet0/1 (999).
I checked the configurations but I didn't find any error. Could you please confirm if there is something wrong in the configuration ?
On MLS :
Configurations :
https://pastebin.com/9QHy72Bg

MLS#show interfaces g0/1 switchport
Name: Gig0/1
Switchport: Enabled
Administrative Mode: dynamic auto
Operational Mode: trunk
Administrative Trunking Encapsulation: negotiated
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 999 (VLAN0999)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: All
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none

On S1
configurations :
https://pastebin.com/yPSU0NUn

S1#show interfaces g0/1 switchport
Name: Gig0/1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 999 (VLAN0999)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: All
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none

Kind regards.

[burleyman]

On the MLS side for the interface put the command: switchport mode trunk

Mike

[a.m]

So, I can't change the native vlan without being in trunk mode ?

[Deepak Kumar]

Hi, 

Then you have to remove the command

"Switchport tunk native vlan <>

Regards,

Deepak Kumar

[a.m]

VTP can't communicate the native vlan ?

[Deepak Kumar]

Hi, 

You are missing a command "Switchport mode trunk"

Regards, 

Deepak Kumar

[burleyman]

Sorry I should have read this more closely.

Did you see the error during the configuration?

Clear the logs and see if the error continues.

After reading everything closer it all looks ok. A trunk will form if one side is trunk and the other to dynamic auto.

[a.m]

The error persists, is it a bug in the simulator ?

[Deepak Kumar]

Hi,

Please attach your lab file.

Regards,

Deepak Kumar

[a.m]

Hello,

Thank you for your interest.

https://mega.nz/#!MfRTlA6T!Fo1mkMFw5E9DSX-3BcmUCUrESqt8uF0IBDNIUAwbPxo

Regards.

[Deepak Kumar · Accepted solution]

Hi, 

You are missing two commands on MLS switch.

interface GigabitEthernet0/1

switchport trunk encapsulation dot1q   

switchport mode trunk  

Regards,

Deepak Kumar

[a.m]

The problem can also resolved also when you do, as you suggested before,
Thank you all for your precious help.
Kind regards!

[a.m]

Sorry, no switchport trunk native vlan 999 doesn't work.

I edited my previous reply.

only, the Deepak kumar's solution work :

interface GigabitEthernet0/1

switchport trunk encapsulation dot1q   

switchport mode trunk  

Regards