INTELLIGENT WORK FORUMS
FOR COMPUTER PROFESSIONALS

Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

vlan mismatch

vlan mismatch

(OP)
Hi

We have a vlan mismatch between our main office and test networks.

The native vlan in the office is vlan1. In the test network their main subnet is vlan1, and the office subnet is vlan3.

I'm trying to link the two networks together and avoid broadcast traffic from the test network. I thought of setting the native vlan for the trunk to vlan3, so office traffic is untagged. How will the office switch then deal with vlan1 tagged traffic coming through the trunk (when the office switch is vlan1 native)?

Thanks

Cammy

RE: vlan mismatch

Only allow VLAN3 on the Test network switch trunk.

What kind of switches do you have?

RE: vlan mismatch

Hi

It is not a major problem to have two different native vlans on a trunk, although you will see errors on the switch console but it won't stop the trunk from coming up. I take it your encapsulation is dot1q since native vlans are not more than mere cosmetic in isl. You could just permit vlan 3 on the trunk using the command

CODE

switchport trunk allowed vlan 3 

and that would effectively stop broadcast from the downstream test network on vlan1 from saturating your trunk link but cdp, vtp and stp would continue to work.

-HTH
-Viconsul

RE: vlan mismatch

(OP)
Thanks for the replies. I need both vlans allowed down the trunk.

The switches I have don't support vlan retagging. We're now planning on removing office network devices from the test side of the network ( and routing it instead )

Cammy

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members!

Resources

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close