Date: Sat, 16 Oct 1999 21:36:54 -0600 From: Wes Peters <wes@softweyr.com> To: jonathan michaels <jon@caamora.com.au> Cc: Chris Dillon <cdillon@wolves.k12.mo.us>, ckwen <ckwen@eembox.ee.ncku.edu.tw>, freebsd-net@FreeBSD.ORG Subject: Re: can two fast ethernet cards work in a freebsd box ? Message-ID: <38094456.B210ECEC@softweyr.com> References: <199910161104.TAA26753@eembox.ee.ncku.edu.tw> <Pine.BSF.4.10.9910161424540.81531-100000@mail.wolves.k12.mo.us> <19991017090323.A23931@caamora.com.au>
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jonathan michaels wrote:
>
> On Sat, Oct 16, 1999 at 02:28:56PM -0500, Chris Dillon wrote:
> > On Sat, 16 Oct 1999, ckwen wrote:
> >
> > >
> > > Thanks to Wes Peters and Martin Machacek.
> > > Now the hub's 100 Mbps LED goes on again after the execution
> > > of ifconfig command. The parameters I set in ifconfig are
> > > "media 100baseTX mediaopt full-duplex."
> > > Neither of them can be omitted.
> >
> > If this really is a HUB as you have been saying all this time, and not
> > a SWITCH, you don't want to be using full-duplex.
>
> ummm, this may be a silly question, if so would you (or
> anybody else) be so kind as to reply off list as to why and
> what the difference would be in this regard
Full duplex can only be used on a network where there are only two
transmitters. Since hubs are a shared resource, connecting multiple
transmitters together, you can only use half-duplex.
Switches do not have this problem, because each switch port is a single
network. As long as you plug only one NIC into each switch port, you
can run that one NIC at full duplex.
> i've just recently gotten a couple of 100basetx nics for my
> three pci based computers and have started to save fro a
> 100basetx hub, i was then told that a swithch would be better,
> especially if i had lots of collisions.
Yes, every machine plugged into a hub is in a shared collision domain.
In a switched environment, the collision domain consists of the switch
and the host, so there are NO collisions. Even an inexpensive layer 2
switch provides these benefits.
> since mving into a new house (700 meters fron teh end of off
> and directly down teh middle of off teh middle of one off teh
> main runways of sydeny international airport. previously ultra
> reliable equipment has becme more than a bit quirky.
It may. A switch will regenerate each of the packets, whereas a hub
only retransmits them and often will induce small timing errors itself.
Unfortunately, even inexpensive switches aren't all that inexpensive.
--
"Where am I, and what am I doing in this handbasket?"
Wes Peters Softweyr LLC
wes@softweyr.com http://softweyr.com/
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