Network switches fall into four basic categories: those that fit into the classic three-tier enterprise network model, and newer data center-class switches currently used mainly by large enterprises and cloud providers that rely heavily on virtualization. These newer switches have density and performance characteristics that can be deployed throughout the data center or to anchor a two-tier (leaf-spine) or one-tier flat mesh or fabric architecture.
You may hear network administrators say something like, “A switch is just a switch no matter who makes it.” In some ways, it’s true; in other ways, not so much.
All switches have basic functionality that includes maintaining a media access control (MAC) address-to-port table, which is used to intelligently forward frames out the right ports to the intended destinations. All switches also use standards-based protocols to segment traffic using the concept of virtual local area networks, 802.1q trunks and 802.3ad port aggregation. They also prevent network loops using one of the many variants of the 802.1d spanning-tree protocol.
But if you look beneath the surface, you find different types of switches have unique characteristics that, when used properly, better optimize the network as a whole. The easiest way to look at these differences is to break them up into the following traditional three-tier enterprise-network design: