X-Received: by 10.58.112.1 with SMTP id im1mr3145443veb.33.1394810782919; Fri, 14 Mar 2014 08:26:22 -0700 (PDT) Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newspeer1.nac.net!border4.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!w5no4431095qac.0!news-out.google.com!bw18ni12450qab.1!nntp.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.posted.gcicommunications!news.posted.gcicommunications.POSTED!not-for-mail NNTP-Posting-Date: Fri, 14 Mar 2014 10:26:21 -0500 Newsgroups: alt.os.linux,alt.os.linux.ubuntu,comp.os.linux.networking Subject: Re: How to set up a spare Linksys WRT54Gv2 as a wired access point network extender References: <87r46bokae.fld@apaflo.com> <9b626$531df921$43da7656$19279@nntpswitch.blueworldhosting.com> <87wqg1m37t.fld@apaflo.com> <1ihvh9p3mvq5bobp4584cqukk8h7q1qfms@4ax.com> <87siqnnb2u.fld@apaflo.com> <87bnxamfoe.fld@apaflo.com> <8761nhl7v8.fld@apaflo.com> <87r465j721.fld@apaflo.com> <12egoeyciezgx$.dlg@example1357.net> From: floyd@apaflo.com (Floyd L. Davidson) Organization: __________ Date: Fri, 14 Mar 2014 07:26:14 -0800 Message-ID: <87eh24kdih.fld@apaflo.com> User-Agent: gnus 5.10.6/XEmacs 21.4.15/Linux 2.6.19 Cancel-Lock: sha1:pF7uowJ4Lrm5InbqEgZ+oYhzWtM= MIME-Version: 1.0 Lines: 51 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 24.237.124.187 X-Trace: sv3-oAWbtcXhNvkBm43QdOa+HcSrkWFE5tO3vrZyx2aNZHuTSCcQxJdbaw0+tGbtiB7lXTOpCGXpvgiOwgZ!qx6WtMJgHKjXzB3cIwttIvRe2Qk/83EprIr/jDC/FG4eDyyFRpizlT4+K8IiKw5aAfpY3e3e X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 4132 Content-Type: text/plain; charset=us-ascii Xref: csiph.com comp.os.linux.networking:2838 mechanic wrote: >On Fri, 14 Mar 2014 04:31:02 -0800, Floyd L. Davidson wrote: > >> As others have alluded, the janitor may not be a design >> engineer, but he will have exactly the same mission goal! > >Yes there's nothing wrong with that as that kind of community spirit >raises morale in the team, and makes clear what it is that gets them >out of bed in the morning. Yep. Maybe design engineers are more critical, and higher paid, but the janitor really does contribute to the mission too! >As to this twisted pair thing, I've no idea what the specs are in >particular cables but no-one seems to have mentioned the purpose of >such a feature (if indeed it exists) - presumably to reduce >crosstalk between pairs, but is that important in Ethernet >applications? Crosstalk between pairs is the main issue with higher speed networking! Almost every difference between a modern CAT5 or CAT6 cable and the typical twisted pair drop cable used for a telephone 100 years ago is specifically intended to increase the speed of data by reducing crosstalk. But... the network interface does not do standards compliance testing! A network interface today is dime-a-dozen mass produced drop in device. The test equipment required to do such testing is not inexpensive. It is probably also worth noting that such test equipment does not measure or even indicate what the twist rate is on a pair. It just measures crosstalk levels and indicates a pass/fail condition, but not a reason for either. If a given cable segment fails though, other tests are available which might (or not) indicate a reason. Time Domain Reflectometry testing can show "impedance bumps" at a given distance from the end of a cable. But again, it doesn't indicate why there is an anomaly. A cable might have been spliced, it might have a bad connection, it might be crimped, it might have a poorly fabricated connector, etc etc. Any of those will show up as a point where the impedance is out of specifications, and it requires a visual inspection to determine what physical the cause is. -- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) floyd@apaflo.com