Order of commands / portchannels + allowed VLANs on TRUNKs

jibbajabba

I am wondering, is there a specific order I have to pass through commands when adding ports into a portchannel with allowed VLANs

Basically the ports were configured

int Gi1/0/18
channel-group 10 mode on
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree portfast trunk

int Gi2/0/18
channel-group 10 mode on
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree portfast trunk

The portchannel itself

interface Port-channel10
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree portfast trunk
switchport trunk allowed vlan 20,21,22,907

I then noticed that the ports were suspended and the logs showed

EC – 5- = CANNOT_BUNDLE2: gi1/0/18 is not compatible with po1 and will be suspended (vlan mask is different)
EC – 5- = CANNOT_BUNDLE2: gi2/0/18 is not compatible with po1 and will be suspended (vlan mask is different)

I tried to shut / no shut the ports without luck .. it only started working once I added the switchport trunk allowed vlan 20,21,22,907 line to the actual interfaces .. From that point on additional VLANs added to the portchannel were passed through fine to the individual interfaces.

I am by no means expert here (just a luser lol) - so any tips are highly appreciated

Zartanasaurus

Adding that statement from the port-channel interface is supposed to copy the commands to the interfaces in the bundle. I add and remove allowed vlans from the po interface all the time. Might be something specific to the 3750 though, gonna test it out.

jibbajabba

This is in a 3750G and it does work once the allow list exist. Now I am not sure if the allow list has to exist or whether this is really just a matter of which order you put the commands in. I just don't know - weird.

Zartanasaurus

Nope that's not it either. Works fine even when using different switches in the stack.

Zartanasaurus

jibbajabba wrote: »

This is in a 3750G and it does work once the allow list exist. Now I am not sure if the allow list has to exist or whether this is really just a matter of which order you put the commands in. I just don't know - weird.

You should be able to just join the interfaces to the bundle, then go into the po interface and enter the configuration. It will be copied to the interfaces. I assume the vlans you're trying to add exist?

ColbyG

Always, always modify the config on the port-channel interface. If, for some odd reason, the config isn't being pushed to the interfaces use the interface range command.