Router on a Stick on a L3 switch?

[visitor68]

Hi...trying to figure out why there would be the need to configure router on a stick using a L3 switch (meaning, the L3 switch is acting as the router), instead of just creating routed SVIs and enabling dot1Q trunking on the port and being done with it...Router on a stick was used on legacy routers that didnt support vlans and had limited interfaces...

[Joseph W. Doherty]

The only purpose I could see for retaining a router-on-a-stick would be if the router has some features you require that are just not available on a L3 switch.

This, I would expect this would be an unusual requirement even though real/pure routers often have features not available on a L3 switch, as those/such features are also often not needed for LAN routing.

[Julio E. Moisa · Accepted solution]

Hi Visitor68,

I agree, You don't need router in a stick scheme if you have a L3 switch, if you want to enable intervlan routing you just execute: ip routing command line globally and also you can create the interface vlan (SVI). 

:-)

[visitor68]

Thanks, Julio. I did find out what was behind my client's thinking: he wanted to avoid running STP instances for SVIs. 

[Julio E. Moisa]

You are welcome,

mmm disable STP is not a good idea, now if he wants to keep a just 1 instance for all the VLANs, he could implement MST.

:-)