Hub/Switch/Router

I'd like to know whats the diffrence between a hub, a switch and a router. I have a general idea but I'm not really sure.

 

http://www.practicallynetworked.com/networking/bridge_types.htm

 

Excellent link from Brett giving an overview of the devices and what they do for a living.

However, for a home LAN (local area network) with only a few systems, the "differences" don't really make a difference to the user. That being said, the fact that you can now get a switch at about the same per-port cost as a hub makes the switch a better idea but for the record:

Switch & hub are similar in function. Router is another thing altogether.

Switch - takes a stream of traffic and puts it to the proper machine. Can do so at the full rated speed of 100mbs (100 megabits per second) and full duplex (two way traffic at the same time) to all the connected devices.

Hub (mostly) also takes the traffic stream and puts it to the intended machine. Maximum speed is 10mbs and half-duplex (can't move "to" and "from" traffic at the same time) and the speed is shared amoung all connected devices.

So a hub with 10 attached PCs and all PCs needing data at the same time might send to each at a real speed of as low as 1mbs. Further losses from collision traffic and possibly as slow as 800-900kbs but only on a loaded hub with every PC getting data at the same time.

Huge difference on a large LAN where the wiring and the PC NICs can all do 100mbs full duplex.

Probably (almost certainly) no difference on a home LAN with 2, 3, 4 PCs when dealing with internet traffic since the internet connection will be a maximum of 1mbs and probably less. The hub will always be faster than the internet connection.

With a hub-controlled home LAN, the only time you should notice speed problems would be with internal data transfers where, if the NICs will do 100mbs full duplex, a switch would move data at least 10 times faster (if all one-way like a file transfer) or more than 10 times faster if there was two-way traffic involved.

My point (finally) is, if you are buying new, by all means get a switch and the switch/router combos are the way to go. But if you already have a hub, don't replace it unless there are problems of some sort.

Added note - if you have a switch and attach a hub to each port rather than a PC, the switch can easily keep all of the hubs moving at full speed since it can deliver to each port faster than the hub can operate.

 

Thank you very much for your replies. That really cleared up a lot of my concerns.