Shoutbox

bah here we go.

Router: at least one router must be used in a network setup, weather it be a harware router, a dedicated machine running linux, or a windows machine running  with internet connection sharing (ICS). it takes signals from one machine and fowards it to another, as well as providing the ip adresses for each connected machine.

Switch: takes the traffic from one connection plugged in and sends it to another connection, weather this be from a user to a user or a user to the internet or w/e. it only sends the data where it needs to go.

Hub: a more primitave version of a switch (but invented first afaik) that takes information from a computer and sends it out to every other device connected to that swict. this uses up bandwidth which is basically just slowing things down. not bad for a home useage but should probably be avoided in a current larger office configureation.

hope this helps :/