Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!peer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!border3.nntp.dca.giganews.com!Xl.tags.giganews.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: Sun, 09 Mar 2014 20:05:18 -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: <79349$531ada84$43da7656$10059@nntpswitch.blueworldhosting.com> <531B1133.3030405@djph.net> <46871$531b684c$43da7656$13519@nntpswitch.blueworldhosting.com> <87r46bokae.fld@apaflo.com> <87iornnqsu.fld@apaflo.com> From: floyd@apaflo.com (Floyd L. Davidson) Organization: __________ Date: Sun, 09 Mar 2014 17:05:08 -0800 Message-ID: <87a9cyoocb.fld@apaflo.com> User-Agent: gnus 5.10.6/XEmacs 21.4.15/Linux 2.6.19 Cancel-Lock: sha1:xAn+gruR0A7cmfa2pxkD5g4ZnsU= MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Lines: 70 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 24.237.124.187 X-Trace: sv3-iePWPS65KS5xSDWqKqRA8hhk56RVQqSpKKco8m5Q97NmmCx/4ySRkUrtgtEiCS3xDy8nnux5lcOg9zr!aMOklVz2X+IpZRGi258EbDw1BRNxdYBn0saP7MB1mZhuaZlg4q2s4RLT8fzZi33pV19gud/c 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: 4410 X-Received-Bytes: 4551 X-Received-Body-CRC: 1421430244 Xref: csiph.com comp.os.linux.networking:2813 DecadentLinuxUserNumeroUno wrote: >On Sun, 09 Mar 2014 10:57:21 -0800, floyd@apaflo.com (Floyd L. Davidson) >Gave us: > >> >>The twist rate differs on *any* cable with multiple twisted pairs. > > Cat 6 has VERY specific twist rates and they differ in the same wire >very specifically. It is not just some lame manufacturing window the >maker of the wire needs to comply with to make the claim of it being a >certain wire. They are specifically (with cat5e and up) two different >twist rates and belong at different locations on the GbE port and >therefore also on the connector that gets you into that port. > > Sure, you may get a handshake with your sub orthodox jumper, but why >differ from what the entire rest of the world does? It makes exactly *no* difference which pair has which twist rate or which pair carries which data. Twist rates are also defined specifically in other cables, but in fact for Cat 5 cable they are defined as: Pair Turns per meter Blue 64.8 Orange 56.2 Green 65.2 Brown 51.7 Note that per TIA/EIA-A and TIA/EIA-B the data will be on the Orange and Green pairs. Green has the highest twist and Orange is the next to the lowest, clearly indicating that twist is not significant to the data rate. If maximum difference were important, the twist rates for Brown and Blue would have been used for Orange and Green. If the hightest twist rate was significant, the twist rate for Blue would have been assigned to Orange instead. But in fact *any* twist rate above 50 per meter is enough. > And no, your jumper will not work correctly on a real network link >that fully taxes the link as a part of its built in reliability testing. The hardware cannot detect which twist rate is used on a pair. > A bad link anywhere in our gateways gets found pretty much >instantaneously. Subbing in a sub par jumper gets noted in the >functional testing, so it must make a difference. Think Nyquist. How does Nyquist relate to cable pair twist? The different twist rates are meant to avoid two pairs laying too close to each other over any significant distance. Using different twist rates has been standard practice with multipair twisted pair cable essentially since Alexander Bell discovered the advantages of twisted pair cables. (Don't think Nyquist, think about open wire line!) > BTW, Floyd.. I consider you as one of the most intelligent folks on >Usenet and always have for a couple decades now. Back when a.e.e. was >more popular. Intelligence may be overrated, and I certainly don't claim to have much. What I do have is a few decades of experience with testing comm cabling. -- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) floyd@apaflo.com