Inter-VLAN routing - ROUTER ON A STICK

The ROUTER ON A STICK is one of the two most common possibilities for inter-VLAN routing.

It consists in creating sub interfaces in a single physical interface of a router.

We have with this configuration the possibility of using a single interface to route the packets of several VLANs that travel through the trunk port of a switch connected to that interface. Enterprise routers are basic product for any business/enterprise.

Do not you know what a TRUNK is? Click here

We can thus configure several IPs of different networks to several virtual interfaces (sub-interfaces) housed in a single physical interface.

We left a bit of the basic routing, which is generally what we learn first, and has a single network connected to each router interface.

Advantages of ROUTER ON A STICK

Easy to implement, it is only necessary to create a subinterface for each VLAN in the Router.

Much cheaper than having a router per VLAN .

Much better latency than having one Router per VLAN .