Router on a stick with 2950 switch?

craigc84

Hi guys,

I'm trying to set up VLANs on my cat2950 IOS 12.1
I have created 3 vlans and assigned ports to each
I have set up Virtual interfaces for each
I have also set up a trunk port which i use to connect my router to the switch

I have set up a router with virtual interfaces

Here's my problem...
Only one vlan interface can be administratively up at a time.
I did some research and found that my 2950 only allows 1 interface to be up at a time due to hardware imitations

Is there a way to set up vlans like this on my switch?

Watching cbtnuggets Jeremy sets this config up with no issues but he is using a layer 3 switch.

Is there something else you need to set up when using layer 2 switches

Cheers

Craig

Thanks

RouteMyPacket

craigc84 wrote: »

Hi guys,

I'm trying to set up VLANs on my cat2950 IOS 12.1
I have created 3 vlans and assigned ports to each
I have set up Virtual interfaces for each
I have also set up a trunk port which i use to connect my router to the switch

I have set up a router with virtual interfaces

Here's my problem...
Only one vlan interface can be administratively up at a time.
I did some research and found that my 2950 only allows 1 interface to be up at a time due to hardware imitations

Is there a way to set up vlans like this on my switch?

Watching cbtnuggets Jeremy sets this config up with no issues but he is using a layer 3 switch.

Is there something else you need to set up when using layer 2 switches

Cheers

Craig

Thanks

Ok, so stop and re-read what you wrote "Jeremy sets this config up with no issues but he is using a layer 3 switch"

Router on a stick is a way of having multiple VLANS with one L2 switch. The router obviously performing the inter VLAN routing right because an L2 switch cannot perform this function.

So router on a stick is a matter of configuring subinterfaces for each VLAN, trunking from the Router to the L2 switch and you're done.

FastEthernet0/0
no ip address

FastEthernet0/0.10
ip address 192.168.10.1 255.255.255.0

FastEthernet0/0.20
ip address 192.168.20.1 255.255.255.0

See where I am going? Of course 99% of the time we use L3 switches for this in which we create L3 SVI's which function exactly like the subinterfaces on the router.


Again, stop and really think why you cannot have multiple SVI's on your L2 switch. If you have multiple SVI's, how will intervlan routing function if the switch does not have the capability to route? Simple, it won't.

The concept here is "Inter VLAN Routing", once you wrap your head around it you will see it's no big deal. Right now the concept is getting you but hopefully with this post you now understand the mechanism that allows communication between VLANS (Routing).