[X Newbies] Ethernet Hub/Switch

[Eugene Lee]

On Mon, Sep 15, 2003 at 08:07:00AM +0000, Chris Walker wrote:
: 
: Can someone explain the difference between an ethernet hub and an
: ethernet switch, since both appear to serve the same purpose.

Take out the word "ethernet" and you have the real question:

	What is the difference between a hub and a switch?

A hub is basically a repeater.  If your computer is connected to a port
on the hub, any data the computer sends out gets sent to all other ports
(and therefore all other computers) on the hub.  This is okay, but it
will saturate your LAN rather quickly.  For example, let's say you have
a LAN connected to the Internet.  You are copying several gigs of MP3s
from Computer A to Computer B, while Computer C is trying to browse
Apple's web site.  If you use a hub, all three computers will experience
slow network data transfer rates because they are all trying to use the
same shared network, and everyone's request for data over the network is
interfering with everyone else's request for data.

This is where a switch is useful.  A switch is like an intelligent hub.
Instead of sending data from one port to all other ports, it creates a
dedicated "virtual circuit" between two ports and data transfer between
the two ports is isolated from the rest of the LAN.  The majority of
network activities happens between two computers at a time.  So the
advantage is that all other ports see an unsaturated LAN.  With the
above scenario, Computer A and Computer B can transfer MP3s at the full
speed of the network (10 Mbps or 100 Mbps).  And Computer C can browse
Apple's web site at the maximum speed of your Internet without getting
slowed down by the MP3 transfer.


-- 
Eugene Lee
http://www.coxar.pwp.blueyonder.co.uk/