Subject: Re: bridges,switch
To: Andrew Brown <>
From: Bill Studenmund <>
List: tech-net
Date: 04/19/1999 15:48:15
On Mon, 19 Apr 1999, Andrew Brown wrote:

> >> In the modern world, there is no difference between a bridge and a switch.
> >> I don't think it's even possible to find a bridge that isn't a "learning
> >> bridge" these days.
> >
> >Well, bridges always tend to have exactly two ports. :-)
> i thought that was a repeater.  :-/

Not in my understanding, though repeaters also have two ports. Bridges and
switches are about the same thing - just differeing in sales terms. The
main thing is that they record which ethernet addresses are on which
ports. When they receive an ethernet packet on a particular wire, if they
know that address is on a different port, they relay the packet. If that
address is on the wire segment they received the message on (that address
already has gotten the packet), they do nothing.

Repeaters repeat everthing they hear.

The difference can be seen below:

NFS-Server <===> NFS-Client <===> Bridge <===> rest of net

(the <===> represents an ethernet connection, say on a thin net, or ports
of a hub)

The rest of your net, the part to the right of my diagram above) won't see
the client <-> server communication. With a repeater, they would.

"Switch"es are the same thing, except that they always have multiple
ports. Someone else mentioned bridges which had more than two ports - now
adays the sales folks call them switches.

Take care,