To illustrate the usefulness of VLANs, let's consider the simple case of a mid-sized company that has a software department and an engineering department. The software department occupies floors one and three, while the engineering department occupies floors two and four, and each floor has its own wiring closet with a switch connected to the company router.
Let's also assume that we want to have separate networks for software developers and engineers, so that the developers can communicate with each other via the developers' network, and the engineers can communicate with each other via the engineering network, but the developers shouldn't be able to access the engineering network and engineers shouldn't ...
