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Community Member

CCNP Switching Etherchannel native vlan mismatch

Big problem on the CCNP   switching exam test.

Etherchannel issue -

switch 1

int range fa 0/3 - 4

  switchport trunk encapsulation dot1q

  switchport mode trunk

  channel-protocol 1 mode passive

  channel-protocol lacp

  switchport trunk native vlan 99

switch 2

int range fa 0/3 - 4

switchport trunk encapsulation dot1q

switchport mode trunk

channel-protocol 1 mode active

channel-protocol lacp

switchport trunk native vlan 99

Basically I have a native vlan mismatch for both interface 0/3 and 4 on both switches. I tried switchport trunk native vlan 1, same result,I tried having one switch with vlan 99 and one with native vlan 1, still errors.  What am I doing wrong, I failed my CCNP switching exam because of this.

4 REPLIES

Re: CCNP Switching Etherchannel native vlan mismatch

First I notice that the line

channel-protocol 1 mode passive

should be

channel-group 1 mode passive (same on other int as well, except the passive part)

I am a student to, so Iabbed it up....got the same results, thats when I did a sho in tr and got this...

Switch#SH INTERfaces TRUNK

Port        Mode         Encapsulation  Status        Native vlan

Fa0/3       on           802.1q         trunking      99

Fa0/4       on           802.1q         trunking      99

Po1         on           802.1q         trunking      1

So when I put the native vlan 99 on Po1, got this :

Switch(config-if)#switchport trunk native vlan 99 (applied to both sides)

Switch(config-if)#end

Switch#

%SYS-5-CONFIG_I: Configured from console by console

sh int tr

Port        Mode         Encapsulation  Status        Native vlan

Fa0/3       on           802.1q         trunking      99

Fa0/4       on           802.1q         trunking      99

Looks like this trunk command needs to be on the port channel interface.  When I did this, it worked.

So you know, I used PT...that sometimes distorts labs.  I will be able to try it on real equipment in the morning.

Community Member

Re: CCNP Switching Etherchannel native vlan mismatch

jimmysands73 wrote:

First I notice that the line

channel-protocol 1 mode passive

should be

channel-group 1 mode passive (same on other int as well, except the passive part)

I am a student to, so Iabbed it up....got the same results, thats when I did a sho in tr and got this...

Switch#SH INTERfaces TRUNK

Port        Mode         Encapsulation  Status        Native vlan

Fa0/3       on           802.1q         trunking      99

Fa0/4       on           802.1q         trunking      99

Po1         on           802.1q         trunking      1

So when I put the native vlan 99 on Po1, got this :

Switch(config-if)#switchport trunk native vlan 99 (applied to both sides)

Switch(config-if)#end

Switch#

%SYS-5-CONFIG_I: Configured from console by console

sh int tr

Port        Mode         Encapsulation  Status        Native vlan

Fa0/3       on           802.1q         trunking      99

Fa0/4       on           802.1q         trunking      99

Looks like this trunk command needs to be on the port channel interface.  When I did this, it worked.

So you know, I used PT...that sometimes distorts labs.  I will be able to try it on real equipment in the morning.

I think that "protocol" instead of "group" is a typo. The switch should give an error if you try to run that command at the first go.

In regards to ether-channel, I simply follow the rule to make sure the Port-channel interface config is exactly matching with the interfaces' switchport config (for eg fa0/3 and 4 in your case).

Hope that helps!

Cisco Employee

CCNP Switching Etherchannel native vlan mismatch

Apply native vlan 99 command on the port-channel 1 as well. This should solve the problem.

Jimmy is right.

Cheers

Sweta

Please rate useful posts.

Community Member

Re: CCNP Switching Etherchannel native vlan mismatch

I always configure the L2 port-channel before I go ahead with interface channel-group configuration. This helps me to keep the configs in sync, as I have more than a 1000 times, faces problems similar to the above one. .

Take a que and configure all the interfaces as follows:

interface po1

exit

int ra gi0/3-4, po1

sw

sw tr en do

sw mo tr

channel-group 1 mo active(or passive)

no sh

exit

least errors., believe me....

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