Router

Routers are layer-3 devices and are responsible for routing, or sending data from one network to another. A router will have multiple network interfaces, with each network connecting to a network or a WAN environment. Routers are typically used to connect the LAN to a WAN environment by having a network interface and a WAN interface connecting to each type of network. The router then passes data from one interface to the other. Routers work with layer-3 addresses, which are logical addresses assigned to the systems that are used to determine how to reach the destination network. Routers use a routing table stored in memory on the router to determine how to reach a system on a destination network.

 

Routers are a great way to filter network traffic as well, because they act as a broadcast domain. Traffic will not cross the router unless it is actually destined for a system on the remote network. Most router administrators do not allow broadcasts to pass through the router.