Communication is the exchange of data. This data or information is split up into packages, that are transferred through the network to the destination.
The decision, which package is transferred to what network partner is made by the router. Router are able to connect several networks. In contrast to a gateway a router does not change the protocol.
Router use their knowledge about the net structure to improve the performance of the network, that means the number of simultanously transferred packages and therefore to overall transfer speed is increased.
The router evaluates routing tables and performs load balancing to distribute the transfer load over multiple alternative routes.
