Enabling VLAN shuts others down

[wrwiii122]

I have four VLANs two are up and running and the other two have been shut down when I changed from dynamic trunk to 802.1q trunk. When I issue a no shutdown on one of the VLANs it goes up but then shuts down a different one. The link and protocol are still up and running and I can see the switch using cdp but can't connect to it on that VLAN that I changed it on. ANy suggestions? I forgot to add that this is a 2950 that I am having these issues with.

[spremkumar]

Hi

i feel ur tyring to configure something like this if not do correct me.

!

interface vlanxxx

no shut

!

interface vlanxxy

no shut

!

incase of 2950 u can have only one vlan interface configured on the box which can be used for management purpose,but you can always enable vlans on the global mode and trunk them via the ports whereever you require or wish to do so.

which is very similar to the following conf lines...

!

vlan xxx,xxxy

active

!

interface fastethernet 0/1

switchport mode trunk

switchport trunk allowed vlans xxx,xxy

!

i hope you are trying to attempt the first scenario which i have mentioned ..if u need more info do pen in.

regds

[wrwiii122]

let me give you some background. This is a loop of 3550's with multiple VLANs propagaing throughout. This one that I am having trouble with is a 2950 branch off of the loop. I am trunking the GBIC port and on the ethernet ports I want to be able to give static to different VLANs. The switch has an IP for each VLAN but I can only get to the one that is active.

[steve.busby]

Edwin is correct, you can only have one active IP address on a 2950. You can have many (I don't remember the exact number) VLANs configured and trunked to the 2950 from your 3550s, but there can only be one active IP address on the 2950.

Just ensure the 2950 is in the same VTP domain as the 3550s and you can put the switchports into their respective VLANs.

HTH

Steve

[wrwiii122]

When you say active IP what do you mean?

[spremkumar]

Hi

The active ip (in C2950)as mentioned by steve can be used by NOC for Maintanence (polling your box,upgrading ios or configs).

using that particular ip you will do all these kinda activities.

But in case of a L3 out there you can do other sorts of stuffs too like intervlan routing etc.,

hope it clears out your query....

regds

[glen.grant]

Layer 3 SVI's (conf t, interface vlan XX) is strictly used for management of the switch thus only 1 can be active , if you want to activate a layer 2 vlan on a 2950 then do a "conf t" vlan XX, enter(XX is the vlan number) . This creates the layer 2 vlan and will show up when do a "show vlan" . I bet your current vlans do not show up when doing a "show vlan" which means the layer 2 vlan has "not" been created .

[wrwiii122]

They are showing up.