Santos:CCNA Sec 210-260 OCG

The Challenge of Using Physical Interfaces Only

So here is the problem: What if you have 50 VLANs? Purchasing 50 physical interfaces for the router would be pricey, let alone the fact that you would also be using 50 physical interfaces on the switch. One solution is to use a technique called router-on-a-stick. Consider Figure 9-1. R3 has one physical interface physically connected to the switch. So, from a physical topology perspective, it looks like the router is a lollipop, and that is where it gets its name. There are several video examples about router-on-a-stick and inter-VLAN routing available on the following YouTube channel: http://tinyurl.com/KeithBarker.