Router is a hardware networking device.
The network device which separate different segments in the network to improve performance and reliability is called router.
A router works somewhat similar to a bridge but it can handle different protocols.
It is used to forward packets from one network to the other.
Routers aims at finding out the best possible route for information or data to travel. It tries to find out the less congested route for data to travel.
A router can be used to connect different kind of networks.
For example, Using router we can connect two LANs or a LAN with WANs.
Disadvantage of routers
Routers are generally expensive.
Routers are difficult to configure.
Routers are difficult to maintain.
But we should remember that routers are very important device. If they fail to function properly then the network services will be significantly disturbed.