VLAN Issue in 2950 switch

[asimafzal79]

When i configure vlans in 2950 and assign an IP into it and issue no shutdown command.At the same time.Vlan 1 will automatically shutdown.for example i create 3 vlans and out of all these vlans only one will be in up states and other will be shutdown automactially.

Kindly advice

[ankurbhasin]

Hi Friend,

Cat2950 is a pure layer 2 switch so only one layer 3 interface can be up and up at a time for management purpose.

Default is vlan 1 but if you want some other vlan to be up and up at layer 3 level , vlan 1 has to go down and is a expected behavior.

HTH, if yes please rate the post.

Ankur

[glen.grant]

You are creating layer 3 SVI's not a layer 2 vlan . If you do a show vlan I bet the vlans do not even show up . The layer 3 SVI is only for manageing the switch thus you can only have 1 active on the box and why the switch will shut the others down . You cannot route anything on this switch you need another l3 box to do that .

[asimafzal79]

Hi,

thanks for reply.Kindly tell me one more thing.if i am in need to create 2 sperate broadcast domain on cisco 2950.i create two vlans and then make truck with layer 3 device suppose 2600 router.I will not give any IP's on VLan(2950 switch) inspite for this i will mention the IP's on sub interfaces of fast ethernet of 2600 router.

Regards,

Asim

[ankurbhasin]

Hi Asim,

Absolutely right!! Now that is known as router on stick model.

You will simply comfigure layer 2 vlans on 2950. Configure one port as trunk and connect it to router fastethernet interface and on that fast ethernet interface create subinterfaces and assign the 2 different ip subnet seperate for each vlan and configure "encapsulation dot1q " under each subinterface.

Now as you said "will not give any IP's on VLan(2950 switch)" but I will recommend you give one ip address to any vlan on 2950 so that you can manage this switch remotely if you want anytime in future becase if there is no ip on 2950 switch you have to manually console to the switch everytime for any changes.

You can also check this link out incase you want to see how your topology will look like and configurations but remember 2950 only supports dot1q for trunking.

http://www.cisco.com/warp/customer/473/50.shtml#diag

HTH, if yes please rate all post.

Ankur