2 VLANS 2 networks on a layer 2 switch

MICHAEL CICCONE · ‎02-15-2007

Hello,

I want to setup my layer 2 switch to have 2 different VLANS and 2 different networks. For example

VLAN 10 10.10.1.1/24

VLAN 11 10.11.1.1/24

I have only one connection to my router. which is 10.10.1.1.

I know I can setup the VLANS. My question is, do I need a layer 3 switch to do this? Since I'll have two different VLANS with Different IP's that will need to be routed. I'm thinking I do, but wanted to check with the experts

Thanks

Mike

sundar.palaniappan · ‎02-15-2007

Mike,

Your understanding is correct. To route traffic between VLANs you need a layer 3 switch/router. However, if your router supports dot1q/isl encapsulation then you can setup a trunk between the switch and the router and make the router forward traffic between the VLANs. This feature is called router-on-a-stick.

HTH

Sundar

MICHAEL CICCONE · ‎02-15-2007

Sundar,

Thanks for the help. I have a 2620, which is pretty old. I'm not sure if it supports dot1q/isl encapsulation or not. I'll have to check that out.

Thanks again

Mike

sundar.palaniappan · ‎02-15-2007

It depends on what version IOS you are currently running in the router. I believe you need an IOS with atleast an IP Plus feature set for this. Try this;

R3#config t

Enter configuration commands, one per line. End with CNTL/Z.

R3(config)#int f0/0.1

R3(config-subif)#encapsulation ?

dot1Q IEEE 802.1Q Virtual LAN

isl Inter Switch Link - Virtual LAN encapsulation

tr-isl Token Ring Inter Switch Link - Virtual LAN encapsulation

As you can see from the above output, the router would show you whether it supports this feature or not.

HTH

Sundar

MICHAEL CICCONE · ‎02-16-2007

Sundar,

Currently, my IOS does not support this feature, but now I know I can upgrade and do what I need to do.

Thanks

Mike

ahmednaas · ‎02-15-2007

You do NOT need an L3 switch to do VLANs. You need an L3 switch or a router to route between them.

What type of switch and router do you have?

MICHAEL CICCONE · ‎02-15-2007

I have a 2620 Router. currently the switch is a foundry switch, but I will be replacing it with a cisco 3524 or 3550. I know the 3550 will do layer 3 so I can go that way. I just wasn't sure if I had a true layer 2 switch if I could do what I wanted to.

devang_etcom · ‎02-15-2007

as far as VLAN configuration in layer2 switch you can do... i mean you can configure the VLANs on LAYER 2 switches... but when ever you are talking about the routing between two different VLAN then you have to have Layer 3 device...

if you have router then you can have intervlan routing by creating subinterfaces... and if you have layer3 switch then you can go for the SVI interfaces...

http://www.cisco.com/en/US/tech/tk389/tk390/technologies_configuration_example09186a00800949fd.shtml

If you have foundry switch then you can have only dot1Q encapsulation as ISL is the cisco propritery...

please rate the post if it helps...

regards

Devang

MICHAEL CICCONE · ‎02-16-2007

Devang,

Thanks for the help... This is what I was looking for. I just need to update my IOS and this will work. Thanks again

Mike