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View Full Version : 80m network cable for sharing broadband - will it work?



element16
16-02-2009, 02:15 PM
My dad wants to save money by sharing his home office broadband with the house computers, but to do so will require at least 80m of cat5e/cat6 patch cable to run between his router and our network switch.

Will there be any speed/delay/signal problems with running this long a cable, or should it be fine?

nofam
16-02-2009, 02:21 PM
Should be fine, provided there's nothing along the cable length that emits EMF - 80m is about the maximum practical length you can go without packet loss.

A cheap, effective way to boost this is to get a really basic data switch, and put this at the end of the 80m cable to boost the signal before kicking it along down another cable.

HTH! :thumbs:

element16
16-02-2009, 02:33 PM
Thanks! Is the data switch you're referring to the same thing as a network switch/hub? If so, we've got powered hubs at both ends, because the router in my dad's office is a combination ADSL 2+ router and hub.

Also, how many computers can you have running off one broadband connection without slowing it down to archaic speeds? We'll probably have at least 3 (up to 5 every so often) PCs using this connection at a time.

Rob99
16-02-2009, 02:36 PM
Surfing/emailing 100+
Downloading 1

Chilling_Silence
16-02-2009, 02:40 PM
Bear in mind that the better majority of the time you're "online" your PC is actually sitting idle, such as when you're reading a page, or email.

We have a rather large home LAN, with a solid 20+ devices connected at any given time. Speeds are pretty much always good until somebody uploads, because we're on a limited-upload plan that really kills us :P

As a general rule of thumb, if you're doing a home or small office network, chances are unless you're downloading large files, you'll never "slow" down ...

Unless you're all watching YouTube or videos that is ;)

CYaBro
16-02-2009, 02:49 PM
The max length any run of CAT5e/CAT6 can be is 90M including any patch leads from wall jack to network adapter.
You can go longer but then the cable is not guarenteed to perform to the CAT5e/CAT6 standard any more.
If you are just running between router & switch then 80M won't be a problem.
But as already stated, keep it at least 30cm away from any power cables.
If you have to cross power cables do it at right-angles.

dugimodo
16-02-2009, 03:11 PM
ok, 2 different lengths, I'll add a 3rd.

The official CAT5 standard was 100Mb for 100metres. Then the Gigabit ethernet standard was designed to use the same cables and run the same distance - 100M. CAT5e and CAT6 cabling are improvements to the cable design to improve noise rejection and loss, but actually aren't rated to run any faster or further than bog standard CAT5.

Different manufactures add their reccomendations, but my point is the standard is 100M not 80 or 90 so you would be fine. The max length is between powered devices such as router / switches / PC's. It starts again any time you pass through one of these. At that sort of long length you need to take care the cable is not kinked or compressed and does not turn any sharp corners, I think the bend radius was 50mm but it's been a while so I may be wrong. Also for CAT 5e and above you can't put your own connectors on or the rating is immediately lost so it would have to be a factory made cable to qualify.

All this aside - generally it works even when people ignore the standards and string any old CAT5 cable around the place with little regard to standard practices. For an example I have a 25M patchcord made out of telephone extension cable with only 4 wires in it. Works flawlessly at 100m ( gigabit needs 8 wires so it doesn't work ), wouldn't reccomend it though was just a LAN party stopgap.

CYaBro
16-02-2009, 03:26 PM
ok, 2 different lengths, I'll add a 3rd.

The official CAT5 standard was 100Mb for 100metres. Then the Gigabit ethernet standard was designed to use the same cables and run the same distance - 100M. CAT5e and CAT6 cabling are improvements to the cable design to improve noise rejection and loss, but actually aren't rated to run any faster or further than bog standard CAT5.

Different manufactures add their reccomendations, but my point is the standard is 100M not 80 or 90 so you would be fine. The max length is between powered devices such as router / switches / PC's. It starts again any time you pass through one of these. At that sort of long length you need to take care the cable is not kinked or compressed and does not turn any sharp corners, I think the bend radius was 50mm but it's been a while so I may be wrong. Also for CAT 5e and above you can't put your own connectors on or the rating is immediately lost so it would have to be a factory made cable to qualify.

All this aside - generally it works even when people ignore the standards and string any old CAT5 cable around the place with little regard to standard practices. For an example I have a 25M patchcord made out of telephone extension cable with only 4 wires in it. Works flawlessly at 100m ( gigabit needs 8 wires so it doesn't work ), wouldn't reccomend it though was just a LAN party stopgap.

I''ll add some more to this :D

90M is generally refered to as the max horizontal length.
The max is 100M but this includes any vertical drops and any passive links such as the patch cable from the wall jack to the network adapter.

I always say 90M is the max length as this allows for a longer patch cable from the wall jack to the network device and at the patch panel to the switch (if required)
If you had your max limit of 100M with a 2M patch cable and then someone comes along and moves the PC and puts in a 10M patch cable then you could have problems.

Chilling_Silence
16-02-2009, 07:05 PM
I was under the impression that Cat5e and Cat6 did Gigabit, not the 100M as stated in a previous post?

johnd
16-02-2009, 08:24 PM
I was under the impression that Cat5e and Cat6 did Gigabit, not the 100M as stated in a previous post?

I think you are right - see http://en.wikipedia.org/wiki/Ethernet for example.

CYaBro
16-02-2009, 08:55 PM
I was under the impression that Cat5e and Cat6 did Gigabit, not the 100M as stated in a previous post?

I think they ment 100M as being 100 metres not speed :D That's I mean in my post anyway.
And yes CAT5e & CAT6 do gigabit speeds if wired correctly.
It uses all 4 pairs of wires as opposed to 10/100 which only uses 2 pairs.

WarNox
16-02-2009, 10:37 PM
80M will be fine, get cat6 and you'll get less interference, probably worth it at that distance as you're nearing the maximum.

Cat5 works at gigabit :D I just upgraded my home LAN and its all wired with cat5, works fine at gigabit speeds. The person I bought the switch from told me that it won't work without cat6, he was wrong.

The theoretical maximum for a home broadband is about 4000 computers, limited by NAT :)

Chilling_Silence
16-02-2009, 11:29 PM
Aaah, thanks for clarifying, after re-reading I see the post probably did mean distance rather than speed.

WarNox, where does 4000 come from?

Rob99
17-02-2009, 12:04 AM
The theoretical maximum for a home broadband is about 4000 computers, limited by NAT :)I would have guesed millions.

dugimodo
17-02-2009, 02:19 AM
yeah I meant 100Metres, and fair call with the 90M - pays to allow for someone plugging something different in, also it is the MAX total distance including all cords.

All 3 support Gigabit speeds, CAT5e and CAT6 are just a little better designed and salesman like to sell things ( or to be nice they also like to play it safe ). I get tired of hearing people say you "NEED" a certain cable type - anything CAT5 and above will work, for long runs or heavy interference areas the higher standards perform better but aren't strictly required. Over short distances say < 20M you can get away with almost anything.

Gigabit is a really tricky design, the 4 pairs have different amounts of twist and therefore end up different lengths, because gigabit breaks the single up and sends in both directions up / down all 4 pairs it has to compensate for this difference in delay when it reassenbles the data - amazing stuff.

Chilling_Silence
17-02-2009, 09:21 AM
Yeah I wouldnt have guessed 4000 either ... Many routers have a limit to the number of concurrent connections they can have open from what I understand, but I dont believe 4000 is a hard-and-fast limit of NAT?

I could be wrong though :D

WarNox
17-02-2009, 10:31 PM
Yeah got that wrong lol I'll go find out where I read it.

WarNox
17-02-2009, 10:35 PM
O yep sorry, went back and re-read where the 4000 came from. Here it is:


Port numbers are encoded in 16 bits. The total number of internal addresses that can be translated to one external address could theoretically be as high as 65,536 per IP address. However, realistically, the number of internal addresses that can be assigned a single IP address is around 4,000.

So maybe I am correct... ?

Chilling_Silence
18-02-2009, 12:55 AM
Where did you find that? Im not sure I understand the context fully :-/

element16
18-02-2009, 09:49 AM
80M will be fine, get cat6 and you'll get less interference, probably worth it at that distance as you're nearing the maximum.

Cat5 works at gigabit :D I just upgraded my home LAN and its all wired with cat5, works fine at gigabit speeds. The person I bought the switch from told me that it won't work without cat6, he was wrong.

The theoretical maximum for a home broadband is about 4000 computers, limited by NAT :)
Yeah, I think going with cat6 will be better in the long run, in case we want to make use of gigabit ethernet later on. That and the quality requirements for cat6 cable are (I assume, since it needs to transfer data at gigabit speeds) more stringent to reduce signal interference.

So, no kinks or severe right-angle bends in the cable? Strange, I never knew that a network connection could be affected that way. Just like a garden hose, eh?

WarNox
18-02-2009, 09:35 PM
That quote is from the CCNA material so I'm guessing its right :D

---

Yeah the more bend in the cable the worse it is, as the wires are crossed to cancel out interference.

dugimodo
19-02-2009, 12:32 AM
So, no kinks or severe right-angle bends in the cable? Strange, I never knew that a network connection could be affected that way. Just like a garden hose, eh?


yep, anything that distorts the twist of the pairs affects the loss of the cable and therefore reduces the length it will work to. That's the reason why bundles of cable are tied with wide velcro strips and not nylon cable ties.

If you bend it too sharp the electrons fall out the corner and pool on the floor....

linw
19-02-2009, 10:09 PM
Is the cable to be run between buildings perchance? If so, you might go here http://www.dslreports.com/forum/r18954781-Other-Cat5e-grounding-question

Chilling_Silence
19-02-2009, 11:05 PM
If you bend it too sharp the electrons fall out the corner and pool on the floor....

:D :D :D