On Mon, 2006-01-30 at 07:42, Claude Jones wrote: > > > > A switch or hub is simply a connection point on a single network. No > > bridging or routing is involved. > Here's where my knowledge tells me different. I thought a switch did do some > simple routing. Doesn't a switch "remember" destinations that are on the > local subnet, and build up tables, only routing signal through that are not > destined for the local destination? The distinction is fuzzy because there are some expensive devices called 'layer 3 switches' that understand IP addresses and can do some routing and filtering based on them. However what is normally called a switch works at the network layer 2, using only ethernet MAC addresses. They learn the hardware addresses of the connected devices as packets are sent from them and once a destination is known they will only forward packets to that destination out the correct port. However, they flood broadcast, multicast, and unknown MAC destinations to all ports so the filtering is transparent. They don't know anything about IP addresses or subnets, though - this is all using the hardware address built into every ethernet device. -- Les Mikesell lesmikesell@xxxxxxxxx
