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Too Many VLANS

I have a campus wide setup with a core 6509 switch connecting seven wiring closets with 4509 switches. The 6500 is also connecting to two remtoe locations using gig wireless. Both connections terminate to Cisco 3750's whcih also have connections to each other creating a triangle for rendundancy.

The 6500 is setup as a VTP server, as are the 4500 switches.

This seems to have been running fine for months, but recently an error has been occuring on one of the 3750 switches. It recieves the following error:

000406: *Mar 14 17:08:02: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/26, changed state to up

000407: *Mar 14 17:08:03: %SPANTREE_VLAN_SW-2-MAX_INSTANCE: Platform limit of 128 STP instances exceeded. No instance created for VLAN123 (port Gi1/0/26).

000408: *Mar 14 17:08:05: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/26, changed state to up

There is only about 30 VLAN's across the entire campus though when you look at vtp status on any switch besides the 6500, it shows 1005 vlans out of 1005 vlans capable active. The 6500 only shows about 200 active VLAN's.

I checked all the configs and could not find any obvious reference to vlan 123 at all, and there shouldn't be.

Where could the vlan creation be coming from?


M. Dante Mercurio

VIP Purple

Re: Too Many VLANS


I am thinking that somebody might have introduced a rogue switch into your network. Can you try and find out what the root is for the VLAN ? Also, not sure if you have VTP pruning enabled (globally, on the VTP server), if not, it might be a good idea to do so...



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