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Cable Wars: Cat 6 vs Cat 7 vs. Cat 5e?
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."
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He wanted to ask the opinion of his peers, not rely on what a manufacturer said or possibly out of date material.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.
It is more productive to voice thoughtful opinions (reply) than to judge (moderate) others.
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:
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?
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.