[c-nsp] 29xx switches, VTP, and max VLANs

[Rolf Mendelsohn]

Hi Chris,

On Wednesday 30 May 2007 02:54:02 Chris Adams wrote:
> I have a network with a bunch of 2924 and 2950 switches, running 802.1q,
> in a VTP domain (the VTP server is a 2924).  I tried to add a VLAN last
> week and hit the 64 VLAN limit in the 2924 (there turned out to be some
> stale VLANs I could remove, so I'm okay for the moment).
>
> If I were to make a 2950 the VTP server instead (with 128 VLAN limit),
> what would happen when I add the 65th VLAN on the 2924s?

1)
The 2950's support 250 Vlan's in VTP (or transparent) config mode. RPVSTP 
(Rapid Per Vlan Spanning Tree Protocol) is only supported in 128 Instances.

i.e. if you change to MST (which is a bit more complicated but more efficient 
given many Vlan's) then you can go up to 250 Vlans.

2) When you add the 65th Vlan on the 2950's the 2924 will probably "wobble" a 
bit and then leave the VTP domain and remain with a copy of it's vlan 
database, but no longer receive updates from the 2950.

HTH
/rolf