3500xl spanning tree limit workaround?

[thessick]

Core 6513 with 90 vlans as vtp server.

We trunk to approx. 50 closets with 3500xl stacks. We need spanning tree for redundant links. The 3500's only support 64 instances and randomly disable spanning tree on all vlans over the 64 limit.

Trunks are pruned to only vlan 1 and two others. It is possible for the 3500 to disable spanning tree on the primary vlan for this switch.

Suggested strategy?

Thank You

[seilsz]

Tom,

Are you pruning the VLANs from the trunks using VTP pruning or manual pruning?

~Zach

[milan.kulik]

Hi,

disable the unnecessary VLANs on trunks using

switchport trunk allowed vlan remove .....

interface config command.

This will stop STP instances (if there are no access ports assigned to these VLANs on the switch).

If you just use VTP prunning without disabling VLANs on trunks, one STP instance is running for each VLAN (VTP prunning only stops sending user broadcsts to switches which don't have any access port in the VLAN, STP is still running in the VLAN).

Regards,

Milan