A Router is a device that connects two networks - frequently
over large distances. It understands one or more network
protocols, such as IP
. A Router accepts packets on
at least two network interfaces, and forwards packets from one
interface to another.
Router's may be programmed to filter out some packets, and to
dynamically change the route by which packets are routed.
Router's often use different media on each interface. For instance,
a router might have one Ethernet port and one ISDN port.