WHICH HARDWARE FOR COMPUTER NETWORKING ?
	Common requirements are: Connect networks of different types, different vendors. Provide common communication facilities and hide different hardware and protocols of constituent networks. Needed for extensible open distributed systems Network adapter : interfaces a computer board with the network medium. Repeater : two-ports electronic device that just repeats what receives from one port to the other. Bridge : a more sofisticated repeater with logic capabilities that filters packets (OSI level 2). Hub : multi-port repeater. Switch : multi-port bridge. Router : links two or more networks (different types too), passing messages with appropriate routing information. It operates at OSI level 3. Must have extensive knowledge of the internetwork (routing tables). Gateway : Similar to routers, links two networks. Can also operate at OSI levels higher than 3.