Vlan2 shuts down when bringing up Vlan3

Unanswered Question
Mar 7th, 2009

Hi, I just want to create 2 vlans. Vlan2 and vlan3. I have created them and they are in the database but when I try and bring up one, the other goes admistratively down and vice versa. Anyone have a idea of what I am doing wrong?

I have this problem too.
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tahseen12 Sat, 03/07/2009 - 20:20

Its a 2950 switch and doesn't support EMI for l3 functionality and therefore only supports 1 SVI active at a time.

Gerard Roy Sat, 03/07/2009 - 21:44

No I don't got it. If I remove the IP from vlan3 (see original attachment) or remove the vlan 3 interface will it work?

Gerard Roy Sat, 03/07/2009 - 22:08

I got it l2 vs. l3 - TOTAL brain fart. It HAS been a while ;) thanks!

jose.solano Mon, 03/09/2009 - 08:49

Check the TAC case collection, I see a issue that you have with its resolution.

Leo Laohoo Sat, 03/07/2009 - 22:58

The 2950, like the 2900/3500XL, will only support ONE (1) VLAN up/up.

Richard Burts Sun, 03/08/2009 - 13:23


There is an aspect to consider that may help to clarify your issue. There is a difference between a VLAN and a VLAN interface. There is a major difference between creating 2 VLANs and creating 2 VLAN interfaces. On the 2950 you certainly can create multiple VLANs (have multiple VLANs in the database) and assign different ports to different VLANs, and trunk multiple VLANs to other devices over trunk ports. This is quite different from creating VLAN interfaces. You can create VLANs without creating VLAN interfaces. Creating a VLAN interface is creating a layer 3 interface. And on layer 2 switches like the 2950 there can be only a single active VLAN interface at a time.

So on switches like the 2950 it is easy to create multiple VLANs but you can have only a single active VLAN interface.



Gerard Roy Mon, 03/09/2009 - 13:41

Rick and everyone thanks!. This clarifies a lot. After pounding on it for a while I cam to the same conclusion.


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