Cable Wars: Cat 6 vs Cat 7 vs. Cat 5e? 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."
Re:True, this guy is an idiot. (Score:1, Offtopic)
:D
Re:True, this guy is an idiot. (Score:1, Troll)
limited thinking (Score:3, Funny)
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... (Score:1)
Fiber is better! (Score:4, Informative)
Peace.
Re:Give him a break! (Score:1)
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! (Score:2)
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" (Score:1, Redundant)
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 (Score:3, Insightful)
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... (Score:1)
CAT 7? (Score:1)
Sigh. (Score:4, Insightful)
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.
http://www.siemon.com/white_papers/01-01-23-sff
http://www.networkmagazineindia.com/200205/kron
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. (Score:5, Interesting)
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 [tiaonline.org] 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:
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. (Score:2)
Cat 7 *does not* exist. Anyone who pays extra money to have "Cat7" installed has been hood-winked or is a fool.
Re:Sigh. (Score:2)
Re:Are you kidding? (Score:1)
Regards, Guspaz.
PCI Fiber NICs do exist... (Score:2)
Perhaps you should check again? 3COM makes a rather nice PCI Fiber NIC, it apparently even does onboard IPSec [3com.com].
Re:Are you kidding? (Score:4, Informative)
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 [ntt-at.co.jp], Lucent OC12 and OC 48 cards here, just to name a few. [lucent.com]
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. [3com.com]
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? (Score:1)
What kind of switching does Fibre support? Can you buy a fibre switch? How much do they cost?
Regards, Guspaz
Re:Are you kidding? (Score:1)
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. [smallbusin...puting.com] 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 [dell.com], 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 [netoptics.com]. 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). [netoptics.com]
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.
Get off your fucking high horses (Score:2, Funny)
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 (Score:1)
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.
WTF? (Score:1)
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 (Score:5, Insightful)
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 (Score:1)
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
Sigh
Vertical
Lease this space. Low Monthly payment!
Re:A worthless article (Score:1)
Cu vs Fibre (Score:3, Informative)
Couple of points. (Score:4, Informative)
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 (Score:5, Informative)
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.
Fiber or Cat 5E (Score:4, Informative)
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.
Jason
Re:Fiber or Cat 5E (Score:2)
Jason
Use of higher-quality TP? (Score:1)
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... (Score:1)