Date: Mon, 08 Jan 2001 10:11:46 -0800 From: David Greenman <dg@root.com> To: Nicole <nicole@unixgirl.com> Cc: ppX <c4@worldclass.jolt.nu>, freebsd-net@FreeBSD.ORG, Tom Samplonius <tom@sdf.com> Subject: Re: Problem with fxp0 card and slowing/dying transmits - now I'm really confused Message-ID: <200101081811.KAA14658@implode.root.com> In-Reply-To: Your message of "Mon, 08 Jan 2001 01:52:55 PST." <XFMail.010108015255.nicole@unixgirl.com>
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> Now I am really confused. > After more testing I have found that sending a file via scp or cat'ing through >sendmail works like a champ if I go to a machine outside of the network. But >seems to be a problem for the same machine when trying to go to a server >connected to the same switch. > OK.. maybe its the switch you say. Me too. Until I just came from putting the >machines on a different switch and still having the same problem. It's also a >completly different make and manufacture of switch. Duplex problems often show up as weird performance problems related to the speed of data transfer, size of the packets, or round-trip time to the destination. This happens because during a duplex mismatch, the full duplex side doesn't retransmit on a collision and if the half duplex side sees traffic on the receive side while it is transmitting it thinks it's a collision and stops sending the packet. So for situations (small packets or larger round-trip latency) where the ACK is unlikely to collide with the transmit, things appear to work okay. In other situations where the ACK collides, performance crawls. > Also one other weird question. What is the real difference between a cable >with 2 pairs and a cable with 4 pairs were 10/100 ethernet is concerned. On >another server that was using a SMC/DEC card I found it would go nuts when it >had a 2 pair cable, but worked Ok with a 4 pair cable. From everything I can >tell, 10/100 ethernet should not care abt the extra 2 pairs. I don't know about the affects of 2 pair vs 4 pair, but one cable related thing I do know will have an affect is stranded vs solid core wire. I've always had problems using solid core wire for any significant length (more than 6 feet) with the Pro/100. Stranded wire on the other hand has never given me a problem even for runs of >100 feet. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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