Date: Mon, 8 Jan 2001 08:57:56 -0600 From: "Jason Smethers" <jsmethers@pdq.net> To: "Nicole" <nicole@unixgirl.com> Cc: <freebsd-net@FreeBSD.ORG> Subject: Re: Problem with fxp0 card and slowing/dying transmits - now I'm really confused Message-ID: <00ce01c07983$630ac220$edcf1f40@pdq.net> References: <XFMail.010108015255.nicole@unixgirl.com>
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From: "Nicole" <nicole@unixgirl.com> > 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. > > Nicole > off to a padded room You'd think that just because the extra pairs aren't used to transmit, wouldn't you. It is probably a good guess that that two pair cables have all four pairs in it but the extra two are not connected? In this case the extra two pairs are not grounded and thus act as antennae. It doesn't take a lot of interference induce errors on a 100Mbp/s Ethernet system. Since you did not explicitly say that you tried multiple two and four pair cables, etc... Other problems may include cheap materials or incorrect RJ-45 connectors. e.g. the cable is solid conductor and the RJ-45 connector is designed for stranded conductor wire. There may be bends in the cable, an excessive amount of untwisting of the pairs at termination points, or the wire may be patched through to many patch panels. Are you sure that it is category 5 cable? Is or was the network punch panels once used to connect telephones? If it was there may be bridge taps laying around. - Jason To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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