Date: Tue, 01 Jan 2002 22:04:49 -0600 From: David Kelly <dkelly@hiwaay.net> To: gregory.lane@anu.edu.au Cc: Kevin Oberman <oberman@es.net>, freebsd-questions@FreeBSD.ORG Subject: Re: Pathetic 11 kbytes/s with ed driver (Netgear EA201) Message-ID: <200201020404.g0244nU03160@grumpy.dyndns.org> In-Reply-To: Message from Greg Lane <gregory.lane@anu.edu.au> of "Wed, 02 Jan 2002 13:15:33 %2B1100." <20020102131533.A93513@nucl03.anu.edu.au>
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Greg Lane writes:
> > Are you sure that this card supports full-duplex?
>
> I have set it to full-duplex using the DOS program which said
> I could, so I would assume so.
>
> > If you are plugged into a 10Base-T hub (and not a switch), your MUST
> > run half-duplex.
>
> There's the problem then. I do have a 10BaseT hub.
If thats the case then there is no point in proceeding. Unless you are
connecting two machines direct without hub.
> > What does ifconfig ed0 show?
>
> $ ifconfig ed0
> ed0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> inet 192.168.128.32 netmask 0xffffff00 broadcast 192.168.128.255
> ether 00:40:05:a2:15:fc
>
> You can't set the duplex within FreeBSD anyway. You must
> use the DOS configuration program.
You stopped too soon in snipping your ifconfig output. Is the media
line which matters. The SIMPLEX on the first line means something
completely different. See how fxp0 is full duplex but fxp1 is not?
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 10.0.0.5 netmask 0xffffff00 broadcast 10.0.0.255
ether 00:d0:b7:1c:cc:66
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active
fxp1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 10.1.0.5 netmask 0xffffff00 broadcast 10.1.0.255
ether 00:d0:b7:1c:cc:32
media: Ethernet autoselect (10baseT/UTP)
status: active
> The box running as my router does report collisions on the card
> plugged into the hub:
Be aware there are early collisions and late collisions. And not all
ethernet hardware reports the early collision which you are monitoring
above. Think the 3Com hardware using the vx driver never tallies early
collisions. Late collisions are very very bad and should never occur
unless hardware or software is broken. Early collisions are not so bad.
Used to be a white paper posted on an employee's home page at sgi.com
with a detailed analysis of collisions. If I remember correctly a 200%
early collision rate works out to a 15% reduction in network thruput.
All because the collision happens so early (within the first 64 octets)
that very little time is lost.
> Another question if you don't mind. I set the box up at home
> on my hub-based network (I took it home over the holidays), but it
> will be used at work on a switch-based network when I'm done.
> Will leaving it at half-duplex have any adverse implications on
> the work network when I bring it in and put it on the switch?
There is nothing wrong with running half duplex on a switch connection
other than half duplex is a bit less desirable than full duplex. It
won't bother any of the other hosts on the network. The switch will
buffer for you just as it will probably buffer your 10M bps to others
at 100M bps.
--
David Kelly N4HHE, dkelly@hiwaay.net
=====================================================================
The human mind ordinarily operates at only ten percent of its
capacity -- the rest is overhead for the operating system.
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