Mood:  special

A router (pronounced /'rautər/ in the USA and Canada, pronounced /'ru:tər/ in the UK and Ireland, or either pronunciation in Australia) is a networking device whose software and hardware are usually tailored to the tasks of routing and forwarding information. For example, on the Internet, information is directed to various paths by routers.

Routers connect two or more logical subnets, which do not necessarily map one-to-one to the physical interfaces of the router.^[1] The term "layer 3 switch" often is used interchangeably with router, but switch is a general term without a rigorous technical definition. In marketing usage, it is generally optimized for Ethernet LAN interfaces and may not have other physical interface types. In comparison a network hub does not do any routing, instead every packet it receives on one network line gets forwarded to the other network lines.

Routers operate in two different planes ^[2]:

• Control plane, in which the router learns the outgoing interface that is most appropriate for forwarding specific packets to specific destinations,
• Forwarding plane, which is responsible for the actual process of sending a packet received on a logical interface to an outbound logical interface.