A router is a hardware device that allows the interconnection of computers in the network. The router is a device that operates in layer three of OSI model. A router uses a routing protocol, which allows it to communicate with other routers and share information with each other to know which is the fastest and most suitable route to send data.
A typical router works in a control plane (in this plane the device obtains information about the most effective output for a specific data packet) and in a forwarding plane (in this plane the device is responsible for sending the data packet received to another interface).
The router has multiple more and less complex uses. In its most common use, a router allows several computers to take advantage of the same Internet connection in a small home or office. In this sense, the router operates as a receiver of the network connection to take charge of distributing it to all the equipment connected to it. Thus, a network or Internet is connected with another one of local area.