|  | 8.4 | The Network Layer
| 8.4.2 | The difference between a router and a brouter
Router A router is a layer 3 device that provides best path selection and switching of data packets. In order to connect two different networks, a router must be used. Routers can be used to segment LANs, creating smaller collision and broadcast domains. But the most important use of routers is as the backbone devices of WANs. Networks consisting of routers, all of which can communicate using routing protocols, can be built to allow very reliable and flexible delivery of data. They make the Internet possible. Brouter A brouter (Bridging Router) is a combination of both a router and a bridge: Acting as a router for routable protocols and a bridge for non-routable protocols. It allows the network to be able to resolve almost all of its connection problems by using one device; therefore, it is very cost effective. However, brouters are decreasing in prevalence, their functions are being incorporated into separate categories of devices: Layer 3 routers and layer 2 switches.