Router on a stick without VLANs?

[clayton2779]

I have a situation where 15 subnets are needed but my switch only supports 8 vlans. I thought that while I was preparing for my CCNA that we did a lab where we created a router on a stick using loopback interfaces without involving VLANs, or did I just imagine this lol. I keep deadending everytime i try this in packet tracer.

Any thoughts?

[Jon Marshall · Accepted solution]

Clayton

The obvious solution is to use secondary address but this does mean that some vlans will have more than one IP subnet attached to it. You could basically assign 2 IP subnets to one vlan and on each subinterface use secondary addressing (note i'm assuming subinterfaces support secondary addressing, it would need testing).

Can't see how loopbacks would help because you still need to allocate 2 subnets per vlan if that is all you have.

Bear in mind also that even if it doesn't work in packet tracer it doesn't mean it wouldn't work on real equipment.

Edit - if subinterfaces don't support secondary addressing then you should be able to still have subinterfaces for 7 vlans and then use the main physical interface for the other 8 subnets. Make sure the vlan that is attached to the main physical interface is the native vlan.

Jon

[clayton2779]

Jon

Thank you for taking the time to clarify this issue for me.

Clayton