Unicast flooding between Vlans

ciscoman309 · ‎03-28-2008

Hi. I have a big network where i see unicast flooding traffic (uft) from other vlans inject in a different vlan (example: uft injection from vlan 1 to vlan 230). I read the document "Unicast Flooding in Switched Campus Networks" but not apply. Any idea? Thank you.

Kevin Dorrell · ‎03-29-2008

Without knowing more about your network topology, I can only answer in general terms.

Have a look for trunks with mismatched native VLANs. Do you use native 1 on all your trunks?

Have a look for links that are forced to trunking at one end, and the other end might be an access port on VLAN 230.

How do you know it is flooded unicast traffic from another VLAN? Look at one of these UFT packets and trace its source MAC address back through the tree until you find its source.

Good luck! Let us know how you get on.

Kevin Dorrell

Luxembourg