Date: Mon, 08 Jan 2001 18:16:14 -0800 (PST) From: Nicole <nicole@unixgirl.com> To: David Greenman <dg@root.com> Cc: Tom Samplonius <tom@sdf.com>, freebsd-net@FreeBSD.ORG, ppX <c4@worldclass.jolt.nu> Subject: Re: Problem with fxp0 card and slowing/dying transmits -SOLVED! Message-ID: <XFMail.010108181614.nicole@unixgirl.com> In-Reply-To: <200101081811.KAA14658@implode.root.com>
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First off, let me say thank You!! to everyone who helped. It seems that problem was a duplex problem, but not from the switch to the server but from the switch, to the switch at AboveNet. Our switch, which I had rebooted several times, was set auto neg for the uplink to their switch and was showing 100MB Half Duplex, No-BP. Since I was playing with the switch remotely and becouse the problem was communication from server to server, I never suspected the connection to the Net. The tranfer speed to/from the server via the Net was very fast. But server to server across the switch was not. However, it seems that after talking with an AboveNet engineer, that their switch was at 100MB/full Duplex. When I forced our switch to that setting (on port 1) connected to their switch. the server to server speed, went to normal. So somehow, the duplex mismatch there, was forcing the in/out bound traffic to take a very high priority over the server to server traffic. When everything possible has been exausted, it must then be something otherwise not thought possible. Nicole On 08-Jan-01 David Greenman wrote: >> 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 nicole@unixgirl.com |\ __ /| (`\ http://www.unixgirl.com/ webmistress@dangermouse.org | o_o |__ ) ) http://www.dangermouse.org/ nicole@deviantimages.com // \\ http://www.deviantimages.com/ ---------------------------(((---(((---------------------------------------- -- Powered by Coka-Cola and FreeBSD -- -- I don't speak for anybody but myself - that's enough trouble -- -- Back Up My Hard Drive? I Can't Find The Reverse Switch! -- ------------------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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