Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Add vlan on a trunk

Hello

If my trunk is in use between two switch, if I use the add command to add another vlan allowed in the trunk, Is there a cutoff network?

5 REPLIES

Re: Add vlan on a trunk

Hello Claude!

Use:

"switchport trunk allowed vlan add x"

and you will have no outage there.

Good luck!

Cheers,

Calin

New Member

Re: Add vlan on a trunk

Thanks a lot.

The addition "add" of a vlan in a trunk does not cut the networking of others vlan allowed in the trunk. Is Cisco has documented this because I found no documentation about that?

Re: Add vlan on a trunk

claude1968,

From what i interpreted, your question is "if I use the add command to add another vlan allowed in the trunk, Is there a cutoff network?

If you dont have the switchport trunk allowed vlan [vlan-id]command already enable on your trunk and you add that command, you will block all other vlans except the vlan you are allowing.

If you already have the switchport trunk allowed vlan [vlan-id] command and add another vlan then yes you will not block any other vlan in the list.

Francisco.

New Member

Re: Add vlan on a trunk

That's perfect. Thanks.

Re: Add vlan on a trunk

by default, all vlans allowed on the trunk link so yes you will because you are limiting the vlan allowed on the trunk. only the vlan you allowed with the "switchport trunk allowed vlan [vlan-id]" command will work on the trunk link.

use the "switchport trunk allowed vlan [vlan-id]" comamnd on both switches to permit the vlans on the trunk link

371
Views
4
Helpful
5
Replies