VLan simple question

[sbalderrama]

Hello,

I just had a probably easy question(s) on vlan basics. first lets say i made 3 vlans on a 2950 switch,

Vlan 1 = 10.0.1.x

Vlan 2 = 10.0.2.x

Vlan 3 = 10.0.3.x

I would like Vlan1 and Vlan 2 to talk to each other, but vlan 3 to be seperate from the vlan 1 and 2 and never talk to each other but of course go to the same gateway.

Do i need a 3500 switch to do this, or can this ben done on a 2950? Also by default do vlans have the ability to talk to each other when created or do they not, And also can you give the commands on how to talk to vlans to each other if by default they do not have the ability to talk to each other?

Thank you

[Leo Laohoo]

Do i need a 3500 switch to do this, or can this ben done on a 2950?

Yes you need a Layer 3 device because you want VLAN 1 and 2 to talk to each other.

but vlan 3 to be seperate from the vlan 1 and 2 and never talk to each other

You'll need ACL.

[sbalderrama]

Great thanks for the info, so i would need a 3500 switch but also need an ACL to seperate vlan 3 from 1 and 2 correct? if so can you give me an example commands? Also lets say i want to add a 2950 to the 3500 switch, do i just need to trunk the 3500 to the 2950 switch and it will still keep vlan 1 and 2 seperate from vlan 3?

Thanks in advance

[Leo Laohoo]

so i would need a 3500 switch

You need a Layer 3 device.  A 3500XL-EN is a Layer 2 switch.  A 3550 is a Layer 2 and you need a hardware upgrade to make it Layer 3.

also need an ACL to seperate vlan 3 from 1 and 2 correct?

Ummmm ... Yes and no.  Traditionally yes.  But if Layer 3 is not going to talk with anyone else but itself you just make sure that VLAN 3 is not routed.

[sbalderrama]

Ok thanks for the reply again,

so maybe i can get a 3560 for the layer 3. So by default to seperate vlans you just make sure that the vlan is not routed?

[cadet alain]

Hi,

As a VLAN= a subnet then you need a L3 device to route between VLANs and this L3 could be MultiLayer switch like a 3550 or 3560 using SVIs( VLAN interfaces) or a router with multiple routed interfaces or a Router on a stick design( one physical interface but multiple logical subinterfaces).

Regards.

Alain.