New VLANs Not Participating in the Spanning-tree Process

[admin_2]

What could be causing new VLANs to not participate in the spanning-tree process after they are added?

I have about 74 VLANs configured in a switching environment with 2 Catalyst 6500s in the core and Catalyst 35xx, 29xx and 5xxx as "desktop" switches.

[#2]

The issue is that the Catalyst 3500xl/2900xl switches support only 64 instances of spanning-tree. As a result, these switches switch to transparent mode VTP when they see more than 64 VLANs advertised by VTP.