At this level, we can generally sum routers up into three different categories: dedicated routers, layer 3 switches, and servers configured with routing capabilities. All of these devices have one thing in common: the ability to forward or route data based on the layer 3 address or, as it is popularly known, the IP address.
Besides providing routing capabilities, most routers will provide additional functionality such as NAT, QoS, and the ability to block broadcast transmissions. The first two are covered later in this chapter, but I would like to briefly explain here why routers block broadcast traffic and provide the limits to what is known as a broadcast domain. A broadcast domain is a collection of devices that can receive ...