L3 Switches and Router on a stick
Posted on 2014-07-28
If I understand L3 switches when configured with SVIs , improves the performance compared to the old method of using Router On Stick.
in the snapshot below, taken from Cisco website, PCs are connected to L2 Switches, assuming L2 Switches are configured with Separate Vlans, then L2 Switches are trunked to L3 Switch.
In this case if foe instance a PC in Vlan 20 wants to talk to another PC in Vlan 30, the traffic will still have to go through the Trunk Link between L2 and L3 Switches , then it gets routed from Vlan 20 to Vlan 30 in L3 Switch, then will come back through the Trunk to L2 Switch Vlan 20 then to the PC.
I wonder if there is any better performance using L3 switch in this case than using Router on a Stick .
To my understanding, The only case where L3 is better in performance than the router on a stick, is when PCs are directly connected to L3 switch and Vlans are directly configured on that L3 Switch as well as the SVIs with IP Routing command.
I could be wrong, but please shade some light on this.