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New Member

Help with changing 2950 native vlan, ip addressing

Today our management interfaces for a store sit on VLAN1. We built out a new vlan just for our equipment and want to begin moving our devices over remotely. I setup the vlan interface on the local site router (2600) and added the new vlan to all the trunk links. I tested this in our lab and have some questions.

1). We want our new vlan to be native (I would think so). I tried the following sequence and failed:

1- Change default gateway of switch/ap to new vlan router interface

2- Make new vlan native on trunk links going to switch/ap

3- On switched configure a vlan 201 interface with ip and do a no shut (kills vlan 1).

I cannot get to the new IP when I do these steps starting at the most remote switch up to the core switch. Am I missing something?

4 REPLIES
Cisco Employee

Re: Help with changing 2950 native vlan, ip addressing

Hi Boshardy,

When you said you have added the vlan interfaces on local site router do you mean you have created subinterfaces on router and provided encapsulation command also?

Also 2950 being a later 2 switch can have only one active layer 3 interface for management purpose so if you "no shut" vlan 201 , vlan 1 will shut down as vlan interface are layer 3 logical interfaces and only one can stay active at a time.

I believe you have created subinterfaces on router and allowed the vlan 201 on trunk from switch to router.

Then do not change the native config first. First no shut vlan 201 so that vlan 1 will go down and see if you have the access of the switch from remote site. You should be having the access.

Once done then change the native vlan on switch first which is connected to router and you will loose the connectivity for sometime and then change the native vlan on router subinterface also.

To chnage the native vlan on router subinterface the command is

encapsulation dot1q 201 native

HTH

Ankur

Bronze

Re: Help with changing 2950 native vlan, ip addressing

Hi,

The native VLAN can be modified to a VLAN other than VLAN1 with the following interface command

Switch(Config-if)#switchport trunk native vlan vlan-id

The router sub interface that recieves the native VLAN traffic must be configured using this command

encapsulation { dot1q | isl } vlan native

To remove vlan1 interface on switch use

no interface vlan1 command in global config to remove it from the switch

and add new interface vlan

HTH

Thanks

Raj

Re: Help with changing 2950 native vlan, ip addressing

I donnot agree with rajinikanthz statement saying that removing the vlan 1 interface, bcoz a native vlan which is a default vlan in all the switches cannot be removed, even if you try to remove by issuing the commnand "no interface vlan 1" on the switch you will get a message "% Default interface VLAN 1 may not be deleted"

as ankuar said once if we enable vlan 201 interface, the vlan 1 interface will shuts down automatically as its is taking the vlan information from the layer 3 logical interface which can have a active interface locally on the layer 2 switches.

New Member

Re: Help with changing 2950 native vlan, ip addressing

If I change the router and switch connected to router to native vlan on the new vlan wouldn't i lose connectivity to to my other switches that sit behind core switch.

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