We have connected 2 cisco switches running pvst+ to 2 non cisco switches(nortel) which support pvst in a full mesh topology. cisco1 is root for vlan 10, cisco2 root for vlan20. cisco1----cisco2 | | | | noncisco---noncisco the trunk links from the cisco to the non cisco switches have native vlan1,but the links inbetween the non-cisco switches have a different native vlan configured and dont allow vlan1. we suffered some stp issue recently and from reading around I gather this could cause issues, and that the native vlan should be configured the same for all switches running pvst+ on all thelinks. can someone confirm?