Router

A router is used to translate information from one network to another -- it is similar to a superintelligent bridge. It selects the best path to route a message, based on the destination address and origin. The router can direct traffic to prevent head-on collisions, and it is smart enough to know when to direct traffic along back roads and shortcuts.
While bridges know the addresses of all the computers on each side of the network, routers know the address of the computers plus the address of all the bridges and other routers on the network. One of the most useful things routers can do is to "listen" to the entire network to determine what sections are busiest -- they can then redirect data around those sections until they clear up.