PVST+ and native vlan on non cisco switches.

[ciscokid2012]

We  have connected 2 cisco switches running pvst+ to 2 non cisco  switches(nortel) which support pvst in a mesh topology. cisco1 is  root for vlan 10 (backup for vlan 20), cisco2 root for vlan20 (backup for vlan10).

cisco1----cisco2
  |               |
  |               |
noncisco---noncisco


the trunk links from the cisco to the non cisco switches have native  vlan1,10,20, but the links inbetween the non-cisco switches have a different  native vlan configured and dont allow vlan1 currently.(My personal feeling from reading around is we need to make the link between the noncisco switches to be vlan1 otherwise it will cause issues. Also we sufferered a spanning treee issue, which maybe due to this.

Can someone please confirm if native vlan1 should be the same configured everywhere? and the consequences of it not being configured on those links.

Thanks

[Reza Sharifi]

Native vlan should be the same on all devices (assuming this is the same for Nortel).  Now, if the Nortel devices don't allow vlan 1 to be configured, use a different vlan as native.  For example: create vlan 999 and make it your native vlan across all devices including the Nortels. As matter of fact, it is a good security practice not to use  vlan 1 and use something else.

HTH