Question : Problem: Role of Router

Can anyone help me in giving details the role of router in the network.. I mean what is the work of router in a network.
Is router used in WAN only or can be use in LAN.
In how many ways routers are classified and can anyone explain me in details why they are classified and how one clasifed router type is different from other in terms of functionality.

Answer : Problem: Role of Router

A routers only job in a network originally was to split broadcast domains in manageable routable subnets. Before routers everything was bridged and large networks were riddled with latency and packet errors and extreme drop rates.

The problem was solved by routers and subnetting address ranges it to routabe groups of network nodes.