cat5e question

[Stephen]

Hello,

I am "IEEE 802.3ab, ratified in 1999, defines gigabit Ethernet transmission over unshielded twisted pair (UTP) category 5, 5e, or 6 cabling and became known as 1000BASE-T. With the ratification of 802.3ab, gigabit Ethernet became a desktop technology as organizations could use their existing copper cabling infrastructure."

Implying that cat5e can be used at gigabit speeds. However, all the cat5e cable I can see in CPC says for 100MHz use only.

Is all cat5e cable suitable for gigabit speeds and if it is, why doesn't the CPC web site say so?

Or should I install cat6 instead?

Thanks, Stephen.

[Ryan]

Hi Stephen,

A few years ago I ran a Cat 5e cable from the media server PC in the back bedroom though the loft and down into the lounge to the PlayStation

1. When I connected my laptop to the cable it provided a solid 1Gb connection.

Cat 5e will provide 1Gb links around your house and will be suitable for what you propose. You'll probably find most of your equipment only supports a 10Mb or 100Mb connection.

Cat 6 cabling will support speeds up to 10Gb per second, depending on the length (around 55 metres max) and equipment it is connected to. Cat

6 also has improved crosstalk characteristics. So it should be a bit more noise resistant.

Having said that I have just re-run the network the house. I don't think I will ever need 10Gb links but with a our first child on the way and only being allowed to make this mess once :-) I used Cat 6 cable.

Hope this helps, Ryan

[tinnews]

Well I have quite long lengths (30 metres in one case) of cat5e cable running OK at 1000Mhz. However having said that I think cat6 will probably be somewhat better at guaranteeing good 1000Mb/s connections.

[fred]

In article , Stephen writes

I think Ryan has summed it up pretty well.

Just one point, make sure you use copper cable for performance and longevity. Avoid copper coated aluminium (CCA) and definitely copper coated steel (CCS) which are sold at attractively lower prices with usually only the subtle initials used to identify their inferior construction.

[John Rumm]

You mean like:

Indeed it can. 1000BASE-T was actually designed to run on CAT5 rather than CAT5e - so the cable actually exceeds the required minimum standard (although is strongly preferred anyway)

Most of the ads suggest weasel words like "Suitable for up to 100Mbps", however, it it meets CAT5e, then it will do gigabit as well.

Might be worth asking their tech support...

Not much point... you only get any benefit if *everything* you wire up maintains the screen connection. The cable is more expensive and less flexible.

For domestic use its worth spending the extra on LS0H cable though.

(I ran CPC supplied CAT5e all round my place, and it all runs gigabit without any difficulties (where supported by the device on the end anyway!))

[John Rumm]

100m is supposedly the limit for a segment on 1000BASE-T

Note that the baud rate on the wire is the same for 100Mb/sec and

1000Mb/sec ethernet (125 Mbaud). The differences are that the physical layer signalling system uses three discrete levels with the 100Mb version and five on the gig version. The gig version also uses two pairs in each direction rather than one. Even the noise immunity is much the same on both, since the gig version uses more sophisticated coding.

[Dave Liquorice]

Pah should have run fibre... 100Gbps or more available. Connectors and the tooling to fit 'em are a bit pricey though.

Had the "flood" wiring here done in Cat5e, that'll be ample even at

100Mbps. A Blu-ray only squirts data out at 40Mbps. If anything is going to be a bottle neck it will be the network switch or the devices themselves, not the cable.

[Lobster]

Could you possibly expand on that a bit? I have a cat5E network which I'm planning on adding a new leg to, round tuits permitting, and I wondered whether I should make that cat6 (which I know nothing about other than apparently it takes more bandwidth?) for the purposes of possible future proofing.

David

[John Rumm]

In fact, ignore me I am conflating issues....

(last time I was using CAT6 it was STP not UTP - however not all CAT6 is STP! Maintaining screen continuity with STP is important)

CAT6 UTP is still stiffer and slightly harder to work (thicker wires), as well as being more expensive. Also a similar requirement applies in that your patch leads etc also need to be CAT6 to derive advantage from it elsewhere. Finally you need to take more care at terminations to not strip back too much length of outer (a suggestion of no more than 1/2" is often made), and also not to untwist any of the pairs more than is absolutely necessary. Its also more sensitive to losing performance with kinks and bends than CAT5e

[Andrew Gabriel]

Yes, and both are correct (almost).

Cat5 does 125MHz (or more correctly in this context, a baud rate of 125M symbols/sec).

To get a gigabit through it, it does a couple of things:

1) It uses all 4 pairs in the cable for both rx and tx simultenously which gives you 4 x 125M baud = 500M baud 2) It sends 2 bits per symbol, giving you 2 x 500M = 1000Mbits. (Actually, it sends 3 bits per symbol, but one of them is used to shape the signal, and is not your part of your data.)

Ethernet is only one of the uses for Cat5[e] cable.

I probably wouldn't bother in a house.

[Steve Firth]

No one will need more than 640K of RAM.

[John Rumm]

3 on 100Mb, a 5 bits/symbol (with TCM) on 1000 IIRC?

[Andrew Gabriel]

That was already in my mind when I wrote that!

Cat 5 will break when we get films that are projected in HD to all 4 walls, ceiling, and floor, in 3D, and the room is on hydraulic jacks, and...

[Graham.]

,

Fool, you missed out The Wurlitzer under the floor.

[Stephen]

Thanks for all the replies.

You are right I do not have gigabit devices but I wanted to be sure to future-proof. Like you said, you only want to have to do this once.

Good luck with your new family.

[Stephen]

Thanks. I'm curious about your flood wiring. How have you done this? A socket in every corner of the room? I wish I had chased wires into the rooms when I had chance but at that time, I never thought I might need a cable anywhere other than by the computer!

If I had put back boxes and conduit in the wall, I'm sure they would have been nowhere near where I wanted.

Thanks, Stephen.

[Stephen]

[Stephen]

Thank you. I saw some telephone cable on offer at CPC and I almost bought some. Luckily I saw "CCS" hidden in the description, like you said it was not particularly prominent and even if it were, I would not have known what that was all about, so your warning came just in time. (I know, I should use cat5e for telephones too).

Thanks, Stephen.

[Stephen]

Is this because a screen not connected acts an aerial receiving interference or are you saying that there's not much point having a screened section if either end you use UTP?

Thanks, Stephen.

[Stephen]

I suppose the problem start when you have three people watching three different blurays in three different rooms. Ok, I don't have three tvs yet but it could happen one day.