Modifying Trunk Allowed vlan in etherchannel

[csaravanan-sym]

Hello,

We have a Production Switch. The etherchannel is configured and we are allowing only selected VLANs on the etherchannel trunk

I need to modify the allowed vlan list in the trunk

Do I need modify the allowed vlan list only in the Port-chanell configuration or do I need to modify the allowed vlan list on all the member interfaces as well

[Limitless1801]

You need to modify the allow Vlans on all the members as well as on the trunk. If you can afford to do them all at once and bring down the port-channel interface, great. Otherwise, you need to do one at a time. Here are the steps:

1. Shutdown a member port

2. Disjoin the member from the channel-group

3. Add the new Vlan

4. Go to the Trunk and add the Vlan

5. Join the member back

6. Enter the no shutdown to bring the port

Repeat steps 1,2,3,5 and 6 for the rest of members. You will see some errors related to VLan mismatch between the port-channel and the members that will last until you finish with all of them.

Let me know if it helps.

[Amit Singh]

I would follow the procedure mentioned by the earlier poster. This is a recommended way to set up the port-channels and chaning the configs for add/deletion of the parameters. I dont know if your ports are contiguous on the switches or not but you can use two of the below mentioned methods to make sure that you dont get through any typo mistakes and bring the network down :

1. If the port are continous, use the interface range commands to have the same config applied to all the ports at the same time and spped up the process. As you are applying the config on multiple ports at the same time, it wil easier to check your config and make sure twice before applying it.

2. You can use smart port macros to have a predefined configuration for the ports and then apply the same config on all the ports by using the interface range command or using the macros individually on all the ports. Please see an example of macros below :

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/25ew/configuration/guide/macro.html

This is just for the operational efficiency.

HTH,

-amit singh