|  | 11.1 | Routing Basics
| 11.1.2 | How routers route packets from source to destination
To be truly practical, a network must consistently represent the paths available between routers. As Figure shows, each line between the routers has a number that the routers use as a network address. These addresses must convey information that can be used by a routing process to pass packets from a source toward a destination. Using these addresses, the network layer can provide a relay connection that interconnects independent networks. The consistency of Layer 3 addresses across the entire internetwork also improves the use of bandwidth by preventing unnecessary broadcasts. Broadcasts invoke unnecessary process overhead and waste capacity on any devices or links that do not need to receive the broadcasts. By using consistent end-to-end addressing to represent the path of media connections, the network layer can find a path to the destination without unnecessarily burdening the devices or links on the internetwork with broadcasts.