2 Replies Latest reply: May 31, 2017 4:40 PM by David RSS

    How could I know what is the native-vlan on the neighbor device?

    Nima

      Hi Guys,

       

      The setup that I have is very simple: Two layer-3 switches are directly connected together. I am receiving "native vlan mismatch" notification. The problem is, I don't have access to the other device to find out what is its native-vlan? How could I know what native-vlan is configured on the other device which is connected to main?

       

      Kind regards,

      Nima

        • 1. Re: How could I know what is the native-vlan on the neighbor device?
          MarcD2009

          Hi Nima,

          It should tell you in the logs on which ports the native VLAN mismatch is on as well as the respective VLAN numbers. Here is an example log for let's say Switch_A.

           

          Apr 2 15:40:29 GMT: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet1/0/23 (200), with [Switch_B] GigabitEthernet1/0/4 (1).


          You can then go into each interface on those respective devices and enter sh run [interface name] to get the configuration information. I have included an example below.


          Switch_A#show run int g1/0/23


          interface GigabitEtherne1/0/23

          description uplink to Switch_B

          switchport trunk native vlan 200

          switchport mode trunk

           

          Switch_B#show run int g1/0/4

          interface GigabitEtherne1/0/4

          description uplink to Switch_A

          switchport trunk native vlan 1

          switchport mode trunk

           

          Do you not have a console connection or anything to the switches for troubleshooting?

          • 2. Re: How could I know what is the native-vlan on the neighbor device?
            David

            Show cdp nei detail

            will show the neighbors native VLAN