wires for gigabit ethernet? cat5? cat6?

[groovin]

dont know too much about gigabit, but was wondering is cat5 sufficient for gigabit?

 

[gunrunnerjohn]

It'll work for shorter runs, but Cat5e should be suffficient, since I think the actual frequency of gigabit is 250mhz, the same as Cat5e. Obviously, better cable is... better!

 

[cmetz]

groovin, cat5e extends the cat5 spec to specify a few metrics that turn out to be important to 1000BaseT and I believe one of the other metrics is somewhat tightened. A good cat5 cable system should also qualify as cat5e. For new installations, always get cat5e as a minimum. cat6 is not strictly speaking necessary for gigabit, but the added headroom makes you more resilient to possible problems and gives you some room to grow.

 

[groovin]

thanks

 

[akers]

I am a little late jumping in in ths one but ....

We have been investigating the various cables for the jump to gigabit at the office. CAT5e at 350Mhz is adequate for Gigabit. CAT6 (500 Mhz) is of course better but is somewhat fragile because of the wire used and the way it is bundled. If you are careful with your installation the price delta is very small so I am going with CAT6 over CAT5e.

 

[cmetz]

akers, I'm interested in this statement:

"is somewhat fragile because of the wire used and the way it is bundled"

My experience - with Berk-Tek LANMark 2000, a high end cat6 cable, is that it's very durable stuff. It has a very substantial polymer/plastic center separator and the wire itself and jacket is also a little heavier than cheap cable. The unfortunate result is that the cable's diameter is significantly increased (maybe 1.5x-2x that of normal cable, but because area follows the square of the radius it's a big loss in bundle capacity), but anyway the stuff I've used seemed pretty darn durable.

 

[Mystical]

there is some information about a new line of gigabit ethernet that runs on cat 3 and cat 5 (long runs at that) at this site: Comtech. You may not have to rewire your building, they say you can use cat5 up to 300 meters. In the tech spotlight section they have an article about gigabit ethernet without rewiring, or something like that. Click read more for the whole article and it has a link to the site that sells the stuff.

Pricing is just a bit cheaper than cisco, but im guessing rewiring your building would cost a lot of cash.

 

[cmetz]

Mystical, all I saw on the link in your post is a company that claims to be able to do 100m (the usual standard) over cat5, not requiring cat5e. Considering that most compliant cat5 installations will also meet 5e, this is not necessarily a big deal. I'd be interested in seeing how this company's equipment performs on cable that meets cat5 but has way out of spec FEXT.

In general, we learned with 100BaseT4 that the niche solution that uses more DSP to try to get you out of upgrading your cable plant doesn't work too well and doesn't get much deployment.