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Cable Wars: Cat 6 vs Cat 7 vs. Cat 5e?

Cliff posted more than 11 years ago | from the if-you-gotta-go-copper dept.

Technology 56

stone22 asks: "My company has decided to install a gigabit link. This will be initially used only for testing purposes, and on the longterm as a backbone for our corperate network. We allready decided to use copper, but what standard ? I've heard about problems using cat 7 cables (cross talk, bulky cables, non-standard connectors) so I could really use some hints from all you cabling experts out there."

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phirst poast (-1, Troll)

Anonymous Coward | more than 11 years ago | (#4392484)

The Future of SLASHDOT.
2002. Slashdot publishes 1,000,000th rumor passed off as actual story. The story generates 480 comments, 263 of which agree with the article, and 107 of which point out it's a rumor and are modded down as redundant. The remaining comments are all "first posts." or posts that contain any rational insight are modded "troll."

2002. CmdrTaco married to a human female, reports are that she does not have 46 chromosomes, however. Fent does display tendency to retardation.

2002. Slashdot parent corporation VA Research^W Linux^W Software stock worth 35 cents. Rumors that AOL, Microsoft, or even Jimmy the hobo who lives under the Longfellow Bridge may buy it.

2003. VA Software bought by Microsoft for a cup of coffee and a donut. All Microsoft-critical articles mysteriously disappear from Slashdot. Bill Gates as Borg logo replaced with Bill Gates as God. (Taco suggested that in order to be "God," or his vision of God, Gates would have to be seen in a NAMBLA T-shirt. Luckily good taste prevails in favor of the old man image in glowing aura.)

2004. CmdrTaco loses virginity, well, not sex with men virginity, that's long since gone, and not sex with anime blow up dolls, this time, real sex.

2004. The WIPO Troll returns again, showering Slashdot in 45,000 copies of the same post: "Lick my crotch hairs." Slashdot, despite running on 18 redundant IIS/8.0Beta6 servers, buckles under the load. The term "Slashdotted" is replaced with "WIPO-Trolled."

2004. Slashdot officially shut down. Millions of screaming, unwashed geeks invade Redmond campus and lynch Bill Gates.

2005. Linus Torvalds and Anal Cox found dead along with six penguins, a tub of crisco and several used condoms. FreeBSD users are glad the insanity is dying.

2005. CmdrTaco rumored to have had sex again, even with constant Viagra therapy, it took this long. He complains, I can be ready to go again in five minutes if I was looking at a nude man, to the dyslexic Fent.

2006. CowboiKneel found dead in hotel room with 56 pizza boxes covering his bloated corpse. Three suffocated gay prostitutes are extracted from beneath his body as police remove it with a backhoe.

2007. CmdrTaco actually has sex again, this time plugging Fent in the ass for a more manlike feel.

2007. BSD is still officially "dying." No word on when its demise will take place. FreeBSD 9 is delivered in perfect working order in a coherent superior, commercially viable and useable fashion with real documentation, the same practice followed since inception. Linux lunatics, after the death of Cox, are still trying to perfect the Trident driver while ignoring the existence of the GeForce 9. Netcraft dies along with all the surveys they held on Microsoft and Linux servers are lost as well.

2007. CmdrTaco starts new weblog to replace Slashdot, creatively named Dotslash. Remainder of Linux users flock to the site and immediate WIPO-Troll it out of existence.

2007. Box running FreeBSD for 6 years sets world record for Unix uptime on consumer hardware.

2008. CmdrTaco has sex with his wife for the first time without thinking of men. He has dawned on the extra sexual pick me up for his twisted mind, small children.

A long long fucking time from now. Malda, fat, poverty-stricken, unrespected and unremembered and living in an appliance box in Michigan with a pickle jar for a toilet comes to a series of epiphanies. The 8.3 file system that made him truncate his nick to an 8 letter series of characters has long been forgotten, and he finally realizes he looks like a fag using it. He also realizes that men's asses look like tacos, especially with the beef pouring out and that his name sounds more like Commander of Ass, since one can command asses because the belong potentially to sentient or living things, it is difficult to command inanimate objects such as food , so one can only conclude he was commanding ass.

He also realized his site was a lame, fad, he sold out, he needed to refactor his shit code and never did it. He also realized that communites such as Fark don*t have this complete asshole running it with gay lameness and compression filters and lame IP blocking bullshit and cheating, pissing and whining and barely anyone trolls it.

We hate you, Fucking Robbie;

he remembers as reams of pages of trolls cry for his expulsion. He also realizes he cant have a computer anymore because he hates the RIAA and MPAA but ran out and gave George Lucas and other shit media companies tons of money to ruin the laws in favor of the omnicorps. He also realizes his socialist and fascist fucking moderation system squelched all the real comments out of view. He also realizes that a full time crew "working" at Slashdot did a shittier job than anyone thought possible.

He also realized he didn*t do SHIT for subscribers and punished them as he would anyone else with page limits, IP blocks, compression and lameness filters. He also realizes Signal 11 is a better man than him and that he is a fucking loser for throwing out S11. He realizes despite being an Open Source advocated, his horrible, unusable unreadable pile of shit called Slashcode was one of the worst projects ever. He realized that retarded journalists are better at reporting the news than Slashdot, that Slashdot news was often inaccurate and unverified.

He also realizes that Aprils fools jokes were really stupid and everyone hated them. He realizes bitchslapping, banner ads, ^H and ^W to show deletion and moderation $rtbl are fucking gay and lame. He realizes this all in a flash as the totalitarian regime he was a small part of constructing (through teaching mobocracy, populism as a rule, hordes of untrained and meritless swarms of people allowed to crucify those who would oppose the thinking of the state) determines his body is a waste of government resources and that he needs to be expelled to a concentration area of the worthless. I figures he would have been the first resident in the camp of the beings deemed worthless to society, along with Jon Katz, but the government, even as a fascist totalitarian regime takes a while to getting around to things.

But Fark is gh3y! (0)

Anonymous Coward | more than 11 years ago | (#4397117)

You have to realise that trolls are all part of the fun of Slashdot, fsckwit.

Lol (0)

Anonymous Coward | more than 11 years ago | (#4392514)

A bit underqualified, aren't you ?
Resign at once and let people with a clue take your job moron.

True, this guy is an idiot. (-1, Flamebait)

Anonymous Coward | more than 11 years ago | (#4392535)

I feel bad for the company that pays this dolt. I understand why the story made it on SlashCrap, because the editors are categorically idiotic, but the editors' sucktitude pales in comparison to this blithering fool.

Most interfaces, cards, and things of this nature have a fucking manual. I have read them myself, while shitting at the toilet at work. It clearly tells you, copper or fiber, the types of cables and lengths to use.

I would also say that fiber is a better backbone that Cu, and CAT 5e has always worked FINE with GigE - because that's what the fucking manual says.

Here, look, a 3C996-BT manual: cted=all&sort=fname&sku=3C996-T []

Direct Link to the PDF: c996_userguide.pdf []

In Section 11, Specifications:

This chapter provides the following information:
. 10/100/1000Base-T Cable Specifications
. Performance Specifications
. Physical Characteristics
. Power Requirements
. Environmental Specifications
Table 6 10/100/1000Base-T Cable Specifications
Port Type Connector Media Maximum Distance
10Base-T RJ-45 Cat. 3, 4, or 5 UTP 100 meters (325 feet)
100/1000Base-T RJ-45 Cat. 5 UTP 100 meters (325 feet)
1000Base-T signaling requires four twisted pairs of Category 5 balanced cabling,
as specified in ISO/IEC 11801:1995 and ANSI/EIA/TIA-568-A (1995) and tested
for additional performance using testing procedures defined in TIA/EIA TSB95.

Connecting the Network Cables
The adapter has one RJ-45 connector, for attaching the system to an Ethernet
copper-wire segment. When automatic link negotiation is disabled, the port can
be configured for 10 Mbps, 100 Mbps, or 1000 Mbps signaling and either
half-duplex or full-duplex operation.
Follow this procedure for connecting a network cable to the Gigabit Ethernet
1 Prepare an appropriate cable. The following table lists the cable characteristics for
connecting to 10/100/1000Base-T ports:
Table 3 10/100/1000Base-T Cable Specifications
Port Type Connector Media Maximum Distance
10Base-T RJ-45 CAT 3, 4, or 5 UTP 100 meters (325 feet)
100/1000Base-T RJ-45 CAT 5 UTP 100 meters (325 feet)
2 Connect one end of the cable to the Gigabit Ethernet adapter.
3 Connect the other end of the cable to an RJ-45 Ethernet network port.
1000Base-T signaling requires four twisted pairs of Category 5 balanced cabling,
as specified in ISO/IEC 11801:1995 and EIA/TIA-568-A (1995) and tested using
procedures defined in TIA/EIA TSB95.
when the cable is properly connected at both ends, the adapter port LEDs should
be functional. See the table in Introduction for a description of adapter port LED
operation. For driver installation and configuration instructions, refer to the
software configuration for that specific driver.

Okay, so now it is clear that you are a waste of time, and a fucking illiterate idiot. Please stop wasting everyone's time, enroll in a TOEFL English class or some shit, and realize your High School in Alabama failed to teach you reading skills. You fucking idiot.

Mental Illness alert!! (0)

Anonymous Coward | more than 11 years ago | (#4392641)

Mental Illness alert!! Anger problem.

That's why you ain't got no friends... (0, Offtopic)

darken9999 (460645) | more than 11 years ago | (#4392793)

Please log on before posting stuff like this so that I can use the "Foe" feature. Thanks.

Re:That's why you ain't got no friends... (0)

Anonymous Coward | more than 11 years ago | (#4392798)

dont worry, I added you as a "dumb twat" already

Re:True, this guy is an idiot. (1, Offtopic)

buzzbomb (46085) | more than 11 years ago | (#4392797)

Why don't you tell him how you really feel?


Re:True, this guy is an idiot. (1, Troll)

virtros (513852) | more than 11 years ago | (#4392990)

True the info is in the manuals and he should have RTFM before posting. However, it WAS a 4:00 AM post on Saturday morning...and you sir are quite grumpy when up past your bedtime. Goodday Sir, V

limited thinking (3, Funny)

n9hmg (548792) | more than 11 years ago | (#4393260)

Well, whoop-dee-doo! Congratulations, you Read an FM. I'll bet the submitter did, too. Do you really think the posters let such questions through in order to substitute some loser's RTFM? We all know how to hunt down specs, standards, and manuals. If that was all there was to it, they could replace /. with a redirect to google. Such questions are not in to provide you with the opportunity to be a snotty little pissant, but for the discussion they stimulate. Here, there's access to the experience, wisdom, and judgement of hundreds (thousands?) of geeks, even if, so often, some snotty little AC demonstrates such limited thinking. Does anybody really think that all the answers are in the standards and manuals? On this topic, for instance, maybe somebody will be able to make the case that there is no reason for catVI or catVII, V works just fine, per the spec. Somebody else may be able to show real benefit, maybe just in certain circumstances, to useing more expensive cable. It is to be his backbone - maybe he should be looking at fibre instead. Whatever.
While I agree that if the submitter didn't even look at such docs as you provided in your crapflood, he IS an idiot, that has no bearing on our responses to the question, and responses to the responses. So, go get a cup of coffee, read something good, and calm down. Review the thread in a couple of days. There'll probably be something in it you didn't already know. Really. It's possible.

Knowledge is power... (1)

hackwrench (573697) | more than 11 years ago | (#4393639)

Of course, none of that tells us why any of that is a good choice. I'm tired of the worlds rush ahead without clear information mentality...The United States is not alone in that department.

AHHH HA HA HA HA!!!! (-1, Flamebait)

Anonymous Coward | more than 11 years ago | (#4392580)

It must suck to be you, stone22 [] . Quit sucking cock and balls [] and get your GED.

Fiber is better! (4, Informative)

vertical_98 (463483) | more than 11 years ago | (#4392622)

While I can't insult you as well as the AC above, I do have to say that if you are seriously considering using this as a backbone pay the extra initial cash and lay fiber. You can go with MUCH longer runs, eliminate crosstalk, and generally find that life is much simplier. But if you have to have copper, Cat 5e UTP cable w/ RJ45s should be more than able to handle your GigE network.


that pays this dolt (0, Offtopic)

E1v!$ (267945) | more than 11 years ago | (#4392627)


What? Give the guy a break.

Oh for fucks sake (-1, Troll)

Anonymous Coward | more than 11 years ago | (#4392708)

stone22, how the fucking hell did you ever get a job?

BTW, this article could have been a better troll if you had also mentioned that your company uses Linux and is thinking of open-sourcing its products under the GPL.

Re:Oh for fucks sake (0, Troll)

Jonny 290 (260890) | more than 11 years ago | (#4392733)

Only if the product was a complete 3D modeling program that he was writing himself, and had no clue as to how to write a program, and if he wanted to put together a Beowulf cluster of Playstation 2's to do it, and if he wanted to steganographically encode pirated MP3's into the 3d models produced by the program, and if he wanted to run Linux on a hacked X-Box to control the cluster, and if he wanted to port some utilities for the application from the obviously dying FreeBSD, and if he then wanted to organize the tasks for the project on some super-cool PDA that those fuckers in Japan will just sit on and never release in the U.S.

Then it'd be the perfect Slashdot troll.

Give him a break! (0, Offtopic)

Anonymous Coward | more than 11 years ago | (#4392803)

It seems like no matter what the question, there are hordes of angry slashdotters lined up to say "Search google, you f*ing moron newbie!!!" or something to that effect.

How the hell are people supposed to find out anything unless they ask? If you think answering a question is "beneath" you, just ignore it, o omniscient one.

Yes, I know a google search (or other search engine) will find 99% of the answers people ask.

Re:Give him a break! (1)

Blkdeath (530393) | more than 11 years ago | (#4392922)

Yes, Google would have unearthed the answer to this question, as would any equipment manual, manufacturer (cable or equipment) or signal specification (IEEE, EIA/TIA, etc.). This individual would have known where to find all of this information had he taken even a six-week introductory course to networking. "This is a picture of a network. These are standards bodies. Any questions? Here's your certification."

But no, this individual decided instead to post to Slashdot and demonstrate both his technical and linguistic incompetence.

You'll pardon me if I take two moments to feel sorry for his company for hiring him, then another moment to take it back, considering they haven't realized that he's not systems administrator material and canned his sorry ass in order to open up a job for one of the many knowledgeable geeks who are presently in desperate need of employment.

Re:Give him a break! (0)

Anonymous Coward | more than 11 years ago | (#4393734)

But they'll ask for experience. And despite being a college grad, have a basement of self-built computers, programs to show, they'll still hire the fellow with the resume that worked at company X or did tech support at University Z. If they are willing to drop the experience limitation, watch the salary drop below non-union factory job pay.

Oh well. Life isn't fair. Darn. Hindsight always rocks. Be considerate and compassionate to others, just don't expect them to be to you.

Re:Give him a break! (2)

LoonXTall (169249) | more than 11 years ago | (#4394053)

Sysadminning (playing with toys like ipfw, op, sshd, etc.) is NOT LAN design and implementation. Go take a sysadmin class and a networking class and see if they cover any of the same material if you don't believe me.

Furthermore, there is no mention of whether he's just kind of expanded into the netadmin job simply because he was there and good with computers. At my dad's company, the netadmins became netadmins because they were the previous datapriests, and the servers got connected to the "Internet". Now they're switching to NT because their Sendmail is an open relay and they have no idea of how to fix it.

Why we say "Ask Google" (1, Redundant)

dasunt (249686) | more than 11 years ago | (#4392953)

Google has a search engine. Its a damn fine search engine. It searches many a site, and caches them in case they are no longer there when you search. Its good for hunting down background information about systems.

However, where google really shines for problem solving is that it archives usenet. Guess what, odds are, your question has already been asked and answered. That's why a lot of people are upset about the recent spat of 'Ask Slashdot' questions.

(meta) Help your fellow users formulate queries (3, Insightful)

yerricde (125198) | more than 11 years ago | (#4393055)

Its good for hunting down background information about systems.

That is, if you're an expert at formulating queries. If you really want to reduce the number of "Ask Slashdot" questions that Google could answer better, then don't just gripe that it should have been an "Ask Google" question. Instead, teach your fellow users how to formulate an effective query.

Funny, I've sent many queries to Google... (1)

hackwrench (573697) | more than 11 years ago | (#4393657)

and I havent been getting any usenet hits... Am I doing something wrong?

Re:Funny, I've sent many queries to Google... (0)

Anonymous Coward | more than 11 years ago | (#4394933)

You'll note that has several tabs at the top, which include 'Web', 'Images', 'Groups', 'Directory', and recently 'News'.

Searching in groups and web would be appropriate for this query, groups is usenet.

CAT 7? (1)

zoomshorts (137587) | more than 11 years ago | (#4392979)

Fiber rules...nuff said.

MS installations (-1, Flamebait)

Anonymous Coward | more than 11 years ago | (#4393012)

Damn, I think we've all just witnessed the birth of another MS fanatic. This idiot is the same kind of moron I see installing MS software whenever they get the chance. In-fact, this is the same kind of moron I see doing just about anything to a system that should have never been done..

Either take a few BASIC networking classes, and go to the efforts to get some BASIC certifications, so you can at least claim you're certifiable. Hopefully, you'll realize you're not cut out for this type of work. Either that, or just save youself the time and trouble, and do us real sysadmins a favor by getting a job you can do, maybe digging ditches, or flipping burgers...

Sigh. (4, Insightful)

Anonymous Coward | more than 11 years ago | (#4393057)

You can really tell that a bunch of sysadmins and not highly-paid wire jockies read slashdot... A cable is a cable, indeed. LOL.

Seriously, in our lab tests, Cat 7 DID have some problems with a number of our servers- and this included non-home-grown stuff like NetApps and Suns. Cat 6 worked just fine. Check a couple of the links here for some more info.

Cat 6 actually did provide us with better benchmarks, btw. as p 2. shtml

The most disturbing thing here is the general downward trend of respect in the Slashdot community. And why did the first post get rated a "4" when it posted info from a NIC manual saying NOTHING of value about cables or comparisons?

On the other hand, a search of Google probably would have found most of this out... but I suppose it's always nice to have a first-hand confirmation from someone who's actually looked at the question.

Re:Sigh. (5, Interesting)

Dahan (130247) | more than 11 years ago | (#4394279)

Seriously, in our lab tests, Cat 7 DID have some problems with a number of our servers

Maybe because there's no such thing as Cat7, despite what cable manufacturers might like you to believe? I could put crap on a string and call it Cat7 cable. Category 6 [] cable is the latest standard for twisted pair cable. While Category 7 may be in the works, it's just marketing for now.

And why did the first post get rated a "4" when it posted info from a NIC manual saying NOTHING of value about cables or comparisons?

It made it up to 5, actually, because it was both informative and insightful. If you want to run GigE, you'll be using NICs and switches. In which case, RTFM for the NICs and switches and they'll tell you what kind of cable to use. What do you mean his post said "NOTHING of value about cables or comparisons"? His post explicitly said Cat5e is what you need if you want to go with copper, but he would recommend fiber:

I would also say that fiber is a better backbone that Cu, and CAT 5e has always worked FINE with GigE - because that's what the fucking manual says.
Sounds like you were more interested in bitching about his post than actually reading what he had to say.

but I suppose it's always nice to have a first-hand confirmation from someone who's actually looked at the question.

And isn't a first-hand confirmation from the manufacturer of the network equipment you'll be using even better than that?

Re:Sigh. (2)

Paul Jakma (2677) | more than 11 years ago | (#4394441)

someone mod parent up.

Cat 7 *does not* exist. Anyone who pays extra money to have "Cat7" installed has been hood-winked or is a fool.

Re:Sigh. (2)

macdaddy (38372) | more than 11 years ago | (#4403101)

Actually... Cat5 NOT Cat5e is what's needed for GigE. 3 is better of course but isn't required.

Why saying "ask Goggle" doesn't work (0)

Anonymous Coward | more than 11 years ago | (#4393087)

This is really trivial, guys. If the twits had the sense to pound sand (and use Google), they wouldn't be asking a bunch of slashies, now would they?

Are you kidding? (0)

Anonymous Coward | more than 11 years ago | (#4393165)

You're running a gigabit link with copper? Are you retarded? Seriously, please answer.

Re:Are you kidding? (1)

Guspaz (556486) | more than 11 years ago | (#4394712)

Last time I checked, they didn't make fiber PCI NICs.

Regards, Guspaz.

Re:Are you kidding? (0)

Anonymous Coward | more than 11 years ago | (#4394825)

Then it's a good thing he said backbone and not client link, huh? You might want to check harder, too, i've used plenty of fiber PCI NICs.

Re:Are you kidding? (4, Informative)

Zeio (325157) | more than 11 years ago | (#4395696)

We work with them all the time, and have for years. One of the earlier supported gigabit fiber cards is the Alteon AceNIC, with the driver being written by Sorensen in 1998 for Linux. Here is a list, more current (no by any means comprehensive):
  1. 3COM 3C996-SX, 3COM 3C985B
  2. Allied Telesyn AT-2970SX/2SC Dual Link1000BaseSX, 2x SC fiber
  3. Asante FriendlyNET GigaNIX 1000SX
  4. Compaq NC6136 Gigabit Server Adapter
  5. D-Link DGE-550SX Fiber Gigabit Adapter
  6. Farallon PN9000SX, HP 1000BASE-SX Gigabit Ethernet LAN Adapter
  7. IBM Gigabit Ethernet SX Server Adapter
  8. Intel PRO/1000 XF Server Adapter
  9. GA621 NetGear Fiber Gigabit Ethernet Card
  10. SMC SMC9462SX Tiger Card 1000
  11. SysKonnect 1000BASE-SX PCI Adapter
  12. Toshiba 1GB Ethernet Adapter.

Many of these are on the second or third revision of the card. I have found the "Tigon 3", Broadcom 57XX (5701) (tg3 and bcm5700, supported in FreeBSD, Linux, and others) 3COM 3C996 (SX and T) to be a very good card, the best of the bunch, as it has advanced packet coalescence, checksum offloading, and has the least number of interrupts with even insane amounts of malformed/attack ingress traffic. The medium seems to make little difference in the short haul.

I have also seen single mode cards for PCI, and I have also been working with single mode POS OC3, OC12 and OC48 cards for PCI.

POS OC3/OC12 for PCI here [] , Lucent OC12 and OC 48 cards here, just to name a few. []

So, with OC48 being 2.5Gbit/sec, I think PCI/PCI-32/33/PCI-64/66 and PCI-X 133 have all seen their fair share of gigabit speed. Most of the cards listen above work rather nicely.

Now, one should use fiber wherever possible, especially for longer hauls. I have OC3 long haul cards for a 7507 at work that are rated to go 80Km in single mode. Multimode fiber transceivers and go up to 500 meters. Consumer grade fiber cards can go up to 10,000 meters as indicated by this 3COM article. []

The point? Backbones are best done in fiber. Most switches support fiber, often they have removable transceivers or cards that let you pick single or multimode. I think that its easier to guarantee throughput with fiber as well, as RF and other interference doesn't play a role, and more often than not you aren't even coming close to the limits of the fiber in terms of distance.

Copper GigE is a good cheap fast short haul way to get servers hooked up to your switches. I have never had any problems using regular CAT 5e, and CAT 6 cabling demands a premium and isn't clear what the benefit is in terms of throughput. As far as better "CATS", I don't think they Spec for CAT 7 or any others has even been drafted, so its mainly marketing drivel at this point.

You will be surprised to see that these cards can all feed PCs far more information than they can take, and you will often see disks trying to keep up, and in certain interrupt driven kernels, if you put the adapter in promiscuous mode (we do this to analyze traffic) you can create kernel live lock because the driver desperately needs to poll the input to prevent userland CPU deprivation.

Again, not using Fiber for backbone is not a good idea. The cost differential is not as bad as it used to be, and you can by most any length of pre terminated SC and LX fiber. In fact, the interesting thing about fiber is the length of the cable barely affects cost. A 10 meter cable and a 100m cable are usually very close in price. It's the endpoints that cost the cash.

Re:Are you kidding? (1)

Guspaz (556486) | more than 11 years ago | (#4398303)

Interesting! I had no idea there were any, let alone so many. But the cost of fibre is just not economical. A GigE over copper NIC costs 60$ US from D-Link (I won't bother quoting D-Link canada's prices, they're all hugely inflated). A fiber NIC from D-Link at the same speed (1000mbit full duplex) costs 310$. That's over 500% the cost, not really usefull for home use or small business.

What kind of switching does Fibre support? Can you buy a fibre switch? How much do they cost?

Regards, Guspaz

Re:Are you kidding? (1)

Zeio (325157) | more than 11 years ago | (#4401409)

There are many, and there have been many ways to utilize fiber for years. As I indicated above, a NIC is not a NIC, I have found the Tigon 3 to be most effective at keeping utilization low under load. If you think a D-Link is going to perform, you would be mistaken, I would venture to guess that in the right situation, with the right packet size, and the right amount of ingress, a more capable 100 mbit controller from 3COM or Intel would outperform a D-Link (which uses a national semiconductor ASIC I believe, that's a guess, but I wont bother to find out because I don't care about D-Link).

I also touched on ingress traffic and live lock in interrupt driven kernels. It's a real problem. Also, speed is relative to packet size (jumbo packets), interrupts coalescence and tcp checksumming offload.

I find that fiber's performance does not denigrate at all as you approach maximum limit in length. I find that Copper is sensitive to RF, and, while gigabit does not have this notion of crossover because it uses all 4 pairs, I hate the idea of crossovers at all (most GE cards now do auto MDX for 10/100).

As I also indicated, there are usually fiber uplinks on switches, as seen here. [] It has 48 ports, and two fiber ports. [$1300 bucks]. This is a typical use, as is suggested by the design. Clearly it is wise to use the 10/100 to connect to got to workstations, and here [] , we see a switch with 24 10/100/1000 ports (Cu), and uplink ports, which can be SM or MM fiber. [$2300]

I would say one would use fiber to connect switches to one another, basically deprecating "spanning" style switches, where one must get proprietary cables and whatnot. This gives the flexibility of moving switches far away, and these switches above have options for single mode which can drastically increase range, making cross-corporate-campus communications as trivial as laying the fiber down and very cheap compared to the days of old when repeaters were used.

I work with a 10/100/1000 combo copper fiber switch, and Alteon 180, and we use that to aggregate switches that span out copper to the lab of machines we use to test various things. I find fiber a joy to work with, and tapping fiber connections is far easier. The aforementioned switch would cost in and about $15,000 new, but on Ebay who knows. Clearly fiber to the desktop is not the intent of using fiber, but not using for backbones is the right choice. Flexible transceivers, cables which are priced right when you want to go far distances, and it isn't subject to RF noise, and is easy to tap - and cheap. The taps for tapping single or multimode fiber [70/30 split] are about $600 [] . The taps for gigabit copper are way over that price (this just came out - its neat, and cutting edge, but according to hearsay not at all easy to do because of the 4 channel system GigE Cu uses). []

So fiber switches are expensive. But they are good, the can aggregate lots of things from far away, and they are generally newer, always managed. The cheapest 100% fiber switches are in the $4000 range, usually starting at 8 ports.

So is fiber for gamers? No. Is fiber a cheap way to hook up your client machines or low bandwidth servers? No. Is it useful to span switches distances near and far, and to allow certain high volume servers excellent access to bandwidth, and be tappable easily and cheaply, yes! I have been very pleased with both the original AceNIC and the Tigon 3 controllers, and the Alteon switches.

Fiber is essentially a distance giver, and most of the NIC I pointed out in my original post have the same ASIC for both the GigE Cu and the Fiber rendition of the card, but I have found that fiber is more reliable, easier to push to the theoretical maximum speeds for a given packet size. I would probably buy going forward Cu 10/100/1000 switches, and span them with fiber uplinks and aggregate them into a fiber switch and give critical routers and servers access to that aggregate switch.

Another thing to pay attention to when buying switches, is the switching fabric. A lot of cheaper switches out there cant handle every single port going full duplex and 1000 mbit. This is where the fabric becomes the theoretical limiter. Be careful of garbage brands, stick to Intel, 3Com, Sun, Cisco, Extreme, Juniper, Foundry and beefy vendors. Intel and 3COM may be seen as cheesy and cheap to hang with the more scaleable vendors, but they build decent stuff for basic use.

Re:Are you kidding? (0)

druse (211317) | more than 11 years ago | (#4395973)

Then you should check again. 3com's had fiber NICs since 2000, IIRC.

Get off your fucking high horses (2, Funny)

jo_ham (604554) | more than 11 years ago | (#4393199)

Yeah, you point out the manuals and information and stuff like that. I'm sure that if he has the ability to post on /. that he has the ability to read.

What if he's looking for user experiences in the real world (you have been in the real world right? You don't just stay in your parents' basement compliling kernels over and over again?).

Manuals will tell you the how to, but not the how good.

I guess he got his answer - ask the slashdot crowd and all the condescending assholes come out of the woodwork to parade their 133t status.

And to stay on topic, I have found that cat5 is perfectly acceptable for gigabit ethernet, but I've only used it point to point, not as a backbone, and then only using a G4 tower and a Powerbook - obviously due to the aestheticly pleasing nature of these computers they can't be 133t, and hence my opinion doesn't count.

Have a nice day.

Re:Get off your fucking high horses (1)

jo_ham (604554) | more than 11 years ago | (#4393232)

and have you considered that this might be a small, non IT company that just wants a way to move big files around?

What if they don't want to hire a sys admin? What if this guy has been given this job by his boss and has never done stuff like this before?

Who knows.

Re:Get off your fucking high horses (0)

Anonymous Coward | more than 11 years ago | (#4394812)

and have you considered that this might be a small, non IT company that just wants a way to move big files around?

What if they don't want to hire a sys admin? What if this guy has been given this job by his boss and has never done stuff like this before?

Then I would not expect them to stay in business much longer if they're not willing to pay the money needed to get a job done right.

WTF? (1)

itzdandy (183397) | more than 11 years ago | (#4393219)

go fibre, period, why would you run a backbone on Cu if their is any though of crosstalk?

Cat6, Cat7? f*k them,
Cat5e is the way to go, its in the spec for GigaEthernet, why not?

but really, go fibre on the backbone

A worthless article (5, Insightful)

Jahf (21968) | more than 11 years ago | (#4393883)

This is one of the most worthless article I've ever seen.

No, not because of the premise, I was actually curious what the answer was myself because I want to lay an inexpensive 1Gb network in my house at some point ("because I can").

It is worthless because of all the people who ridiculed the poster with the various RTFM and "look it up on Google" responses. Most other responses were to use something (fiber) that the poster seems to have obviously ruled out (maybe cost, maybe convenience, doesn't matter), so those don't help much either but at least they were trying.

He wanted to ask the opinion of his peers, not rely on what a manufacturer said or possibly out of date material. Most of the responses trashed him.

Why do people bother to take the time to produce non-responsive or patronizing answers? If you don't like the question, or you think he should spend his time elsewhere to get the answer, then simply don't post.

A lack of response is a much better way to get someone to go away than to waste your time writing and the time of everyone who pops in to see what the consensus was.

Re:A worthless article (1)

vertical_98 (463483) | more than 11 years ago | (#4396050)

I'm sorry my advice to use fiber over copper, bothered you.

I'm so sorry, I'll even explain to you why I gave that recommendation.

Mr. stone22 is going to go buy Cat 6 or Cat 7 (or what ever the company wants to call it, 6e, 6xp) and pay some joe (or do it himself) to run copper. Two or 3 months from that time he is going to notice that a run is operating at less than GigE speed (maybe less than 100base speed). He is going to have to find out why. Did the joe who ran it drape it over a florescent light? Around an electrical junction box? Put a kink in the cable? The troubleshooting list goes on. He looks bad because the new network isn't working.

If he lays fiber, half of his troubles go away. If he has to use copper he can then say to the powers-that-be, 'Yeah, we can use copper, but we will wind up paying more in the long run.'

If you want to run GigE in your basement, use Cat 5e. It was good enough for GigE before Cat 6 was a reality. If Mr stone22 wants to connect his servers to his hubs, he can use Cat 5e also.

So to answer the orginal question: I would use Cat 5e


Lease this space. Low Monthly payment!

Re:A worthless article (1)

Jahf (21968) | more than 11 years ago | (#4403674)

It was one specific answer that was the problem, and if the only issue had been people who posted a response that was not in answer to the specific question (ie, fiber when it wasn't a consideration), I wouldn't have cared. The problem was almost every response was negative or out of scope. It was not just about your post (you weren't the only person to post about fiber), which I understood before the clarification.

Cu vs Fibre (3, Informative)

rerunn (181278) | more than 11 years ago | (#4393904)

Try here []

Couple of points. (4, Informative)

FreeLinux (555387) | more than 11 years ago | (#4393982)

First, you don't give enough information in the article for a really good answer. You say that you want to lay a backbone cable but, you don't give details like the distance it has to traverse or the environment it will be in. You also fail to say how many nodes might be directly attached to this backbone. These are important details in the decision process. That said, read on....

I would have to agree with some of the other posts, you should use fibre. The other posts don't say why you should though so, here's why.

First, fibre is not going to be a lot more expensive than good copper. Sure, it is a little more but, the extra cost is worth the benefits. Benefits include increased distance, no interference at all and, most importantly, room to grow.

In laying a fibre cable, even a small one, you don't have a single data path, as you do with Cat 5-7. Even small fible cables usually bundle three or more pairs in the cable. That means that you can VERY easily double or triple your bandwidth in the future by lighting a second pair. Or perhaps you need a completely separate data path for some other service like maybe you want to interconnect a couple of legacy PBXs, or a video conferencing system, or a security system, who knows what.

The next thing is that fibre gives you even more room for growth. Sure GigE is great but, will it meet your needs in the long term. Already 10GigE is a reality and 40GigE is well on it's way. These can easily be implemented in the future, if you have fibre. I doubt however that Cat 5-7 will ever run 10Gig and definitely not 40Gig.

There is also a technology called Dense Wave Division Multiplexing (DWDM) that uses multiple lambdas or wavelengths on the same fibre pair. Using this technology it is possible to have 64 data paths on a single pair of fibre, that's 128Gbps aggregate bandwidth!!!!! That's all over fibre. With Cat 5-7 though, you will never have more than 1Gbps and only one datapath.

Fibre is definitely the way to go for a backbone solution. I hope this helps.

Cat 5 is fine (5, Informative)

Matt_Bennett (79107) | more than 11 years ago | (#4394434)

I design and test the physical side of ethernet for a living, so I think I state with all honesty and some authority that using anything more than cat-5 cable is wasting money. Kinda like buying 94 octane when your car is designed for and runs fine on 87. It has more capacity than you will ever use. Ok, true cat-5 cable may be hard to find, so when I'm saying cat-5, I'm also mean cat5e. I agree with the other posters that fiber is the way to go for a backbone, but copper is quite a bit cheaper, and pretty reasonably priced. According to the Ethernet spec, fiber is actually held to a higher standard in terms of bit-error rate (fiber is 10^-12, where copper gigabit is 10^-10- I'm pretty sure, I have them in spreadsheets to check against, but anyway, fiber is better) On the other hand, on the interfaces I've tested, the BER on maximum loss (copper) cable is usually far better than 10^-10 so that isn't much to worry about.

Be careful if you are thinking about installing fiber for possible use for 10GbE- there are a bunch of standards, and most of them seem to be incompatible with most current types of fiber, such as requirinig very small diameter single-mode fiber. At the moment the 10GbE world appears to be dominated by the long haul guys, not the LAN manufacturers, so cheap connectorization/fiber is not necessarily high on their priority list.

Remember to keep the length under 100m (as it says in the spec) and don't go through a lot of patch panels (since each connector adds loss). If you are going for maximum length, be very careful how you cut and crimp the cable- the more you can maintain the twist in the wire the better, and the more matched each wire in the pair is, the better.

Interesting fact: Since the loss of cat-5 cable is not well defined per unit length, The test cables (for 100Base-TX) are not specified in terms of length, they are specified in terms of loss. The maximum length cable that you test to is not a 100m cable, it is a 10dB loss at 16MHz cable. With good quality (cat5e) cable, that works out to around 135m.

Re:Cat 5 is fine (0)

Anonymous Coward | more than 11 years ago | (#4396870)

All good, but the initial analogy is flawed. Putting higher octane rated gas in a car not designed for it will, if anything, reduce performance.

Fuel with higher octane requires higher pressures/temps to ignite, so high-performance engines that run higher compression ratios need it to work properly. Lower performance cars with lower compression will have trouble fully igniting the fuel.

Single Mode fibre if you have a choice (0)

Anonymous Coward | more than 11 years ago | (#4394501)

You've really not given enough info in your question for anyone to make even close to an educated guess. All things being equal, if it were me, I would have several pair of Single Mode fibre installed. You will probably have to spend a bit more upfront on the installation (vs multimode) and on your connectors (ie you'll need LX GBICs, etc) but you will be 'future proofing' your backbone for upcoming technologies (ie 10Gig, 100Gig, etc). If you can only do copper and you are within the distance limitations of the 1Gig spec, then Cat5E will do....but you'll never get much more than 1Gig out of copper wiring.

Fiber or Cat 5E (4, Informative)

JLester (9518) | more than 11 years ago | (#4395393)

You'd really be better off going with fiber for gigabit. Yes, Cat5e (and regular 5 if terminated correctly) will run gigabit, but there are some idiosyncracies that you might run into. Your NIC manuals should specify the requirements, I can't remember them off the top of my head. Also, we've found that different vendors support gigabit in slightly different ways on copper. We can't get SMC 1000-BaseT and Cisco 1000-BaseT to talk to each other. We ended up swapping out all our 1000-BaseT links to fiber and haven't had any troubles since.

So, go fiber if at all possible. If you absolutely have to use copper, use 5E cable from a reputable vendor (Belden, Berk-Tek, Mohawk, etc.) and use GOOD jacks and patch cords. I prefer Panduit and spec it for all our jobs, but others also make good stuff. Don't scimp on the patch cords either, these cheapies that you find many times don't test real good. Go for 5E rated patch cords with the short plugs and gold contacts.


Re:Fiber or Cat 5E (0)

Anonymous Coward | more than 11 years ago | (#4396128)

and regular 5 if terminated correctly
do I use an LVD / HVD or an SE terminator?

Re:Fiber or Cat 5E (2)

JLester (9518) | more than 11 years ago | (#4399304)

Don't be an idiot, termination in this respect means terminating the cable onto the jack/patch panel.


Use of higher-quality TP? (1)

st63z (535955) | more than 11 years ago | (#4395819)

I agree that Cat 6 is already superfluous for standard applications such as GigE Ethernet that operate in the 0-100MHz band (though theoretically it may give you somewhat more headroom against sloppy terminations in terms of overall testing qualifications).

I guess higher-quality TP can be useful as a general-purpose wireline carrier for a wide range of analog/digital signalling (through the use of baluns and media converters). If I remember correctly, Belden had some nice info on this. With a good active balun you can carry up to 4 channels of baseband (and limited broadband A/V), USB, Firewire, whatever. Including home run distribution.

When my house was built 2-3 yrs ago, Siemon's TERA System 7 (impressive 1GHz non-RJ termination system) was already being prototyped. Unfortunately, Alcatel's "draft Cat 7"-level cable (600MHz fully pair-shielded TP) wasn't available yet and I couldn't find anything else. So I went with Mohawk's 2nd-gen GigaLAN "Cat 6 plus" UTP (though Berk-Tek and others were close competitors) along with some Commscope 2+2 bundled cables. And mostly Siemon System 6 and Leviton for the termination (again, Hubbell, Panduit, etc, were all very similar). Note that back then Cat 6 hadn't officially been ratified yet.

Tip #1: Terminating the 22AWG Mohawk UTP with its thick jacket and crossweb can be a pain on those closely-packed plates/panels.

Tip #2: Try your local supply distributor (Anixter, Anicom, Graybar, etc) to see if they'll sell you these bulk spools for much, much cheaper than retail Cat 5 equipment. Places like DataComm Warehouse is also good, but they don't usually stock the more esoteric structured cabling parts.

The Only Stupid Question is the one thats never... (1)

The Analog Kid (565327) | more than 11 years ago | (#4396801)

asked. Don't be so mean to him, you have to start inexperianced once. Maybe he wants a second opinion because there might be a better solution than what he read about.
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