I am trying to configure multiple vlans on a 2950T-24 with IOS 12.1(22)EA2 and it seems that only one vlan can be up at a time. Each time a new vlan is created is active, but all others including Vlan 1 are shutdown.
On layer 2 switches you can have only one active VLAN interface. VLAN 1 is the default interface. If you add a second VLAN interface then vlan 1 interface will be shut down. This VLAN (layer 3) interface is used for management of the switch and doesn't route user traffic that traverses the switch.
On the other hand, if you want to create VLANs to assign ports to different VLANs then you need to configure VLANs in the vlan database mode as seen below. Then you could configure the uplink ports to be a trunk port to carry traffic for all VLANs to/towards the layer 3 gateway.
Switch(vlan)#vlan 2 name Admin --> Name is Optional
You can also create VLANs using the new method, which is creating them in configure terminal mode. Using this method will add the VLANs to the running configuration and the IOS will automatically add them to the VLAN database. I believe this is now the recommended method.
This comes up all the time people get confused with layer 2 vlan creation with the layer3 SVI which is used to manage the switch .The layer 3 interface (interface vlan XX) is strictly used to manage the switch and you can only have one active at a time and the switch will shutdown the other one . And yes you can create layer 2 vlan in global mode and as cisco likes to put it the vlan database is being deprecated , fancy way of saying they are eventually getting rid of it .
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