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nightfrost
Apprentice
Joined: 07 Dec 2004
Posts: 293
Location: Sweden
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 Posted: Mon Feb 07, 2005 6:26 pm Post subject: connecting to computers with non-cross-wired cable? |
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Hi,
I was wondering if there's any way to connect two computers with a non-cross-wired cable? Does anyone know of any good turorials concerning networks and such? I really have no idea about anything when it comes to networking, and so I don't even know which keywords to search with... |
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tuxmin
l33t
Joined: 24 Apr 2004
Posts: 838
Location: Heidelberg
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| Posted: Mon Feb 07, 2005 6:34 pm Post subject: |
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This works only with Gigabit NICs and better. For slower NICs you need a crossover cable or a switch/HUB.
There is a really good networking HOWTO (Linux related) here.
Hth, Alex!!!
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nightfrost
Apprentice
Joined: 07 Dec 2004
Posts: 293
Location: Sweden
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| Posted: Mon Feb 07, 2005 6:36 pm Post subject: |
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Thanks a lot for the fast reply  That link seems very good. I'll start from there. Thanks again. |
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CriminalMastermind
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 132
Location: toronto
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| Posted: Tue Feb 08, 2005 8:28 am Post subject: |
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| tuxmin wrote: |
For slower NICs you need a crossover cable |
umm, i don't think this is right quite right.
the reason you need a cross over cable has nothing to do with the speed of the nic.
if all nic's listen for comunication on, lets say pin 1 and send out information on, say pin 2, then a cable without a cross would connect pin 1 to pin 1, and pin 2 to pin 2. so both nic's would be trying to send information down the same wire and listening for replies on another wire (one where nether of them are talking).
so the cross connects pin 1 of nic 1 to pin 2 of nic 2, and pin 2 of nic1 to pin 1 of nic 2. now data gets sent down a wire with someone listening on the other end.
some getto asci art.
no cross
| Code: |
nic 1 nic 2
pin1<------>pin1
pin2<------>pin2
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cross
| Code: |
nic 1 nic 2
pin1<--\/-->pin1
pin2<--/\-->pin2
better drawn in asci without trying to put the twist in the cable and swaping the pin's.
pin1<------>pin2
pin2<------>pin1
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some nic's do detect that they are connected with a strait through cable when they need a corss over and will internally switch there send and receive pins. i don't know how popular this is, i'm told apple nic's do it.
a hub/switch gets around this because they already have the pin's set up like they will be connecting directly to a nic.
hope that helped.
ps, sorry, i don't know of any other online networking tutorials.
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j-m
Retired Dev
Joined: 31 Oct 2004
Posts: 975
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| Posted: Tue Feb 08, 2005 9:44 am Post subject: |
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| CriminalMastermind wrote: | | tuxmin wrote: |
For slower NICs you need a crossover cable |
umm, i don't think this is right quite right.
the reason you need a cross over cable has nothing to do with the speed of the nic.
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No, you are wrong. Gbit NICs use all 8 wires, 10/100 use only 4 wires. |
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CriminalMastermind
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 132
Location: toronto
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| Posted: Tue Feb 08, 2005 10:00 am Post subject: |
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| j-m wrote: | | No, you are wrong. |
| j-m wrote: | | Gbit NICs use all 8 wires, 10/100 use only 4 wires. |
i wasn't really saying that only 2 wires were used in communication... it was just an example. the number of wires in use doesn't really effect what i was talking about. i was just given general theory.
so are you saying there is no such thing as a gigabit ethernet crossover cable?
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transienteagle
Apprentice
Joined: 24 Dec 2003
Posts: 190
Location: UK
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| Posted: Tue Feb 08, 2005 10:17 am Post subject: |
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| Quote: | | so are you saying there is no such thing as a gigabit ethernet crossover cable? |
Correct.
You could in theory uses a cross over cable but the nic's would drop to 100 (providing that they autosense of course)
rgds
TE |
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CriminalMastermind
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 132
Location: toronto
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| Posted: Tue Feb 08, 2005 10:31 am Post subject: |
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| transienteagle wrote: | | You could in theory uses a cross over cable but the nic's would drop to 100 (providing that they autosense of course) |
i didn't say... can you use a 100/10 crossover cable for a gig network.
i'm pretty sure that gig ethernet does have cross over cables, though i have never used one.
a quick search on google turnd up some info on how to wire one.
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AnDuR82
n00b
Joined: 04 Feb 2005
Posts: 3
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| Posted: Tue Feb 08, 2005 11:08 am Post subject: |
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Hi to all.
Before anything I've see some error
the EIA/TIA 568A standard provide this spec.
Couple 1-2 Orange =Tx Signal
Couple 3-6 Green =Rx Signal
Couple 4-5 Blu = Not actually used, for next use
Couple 7-8 Brown = Same as above
and the Gbit network card, the 10Gbps too, use only the first 2 Couple, but for better performance you need to use Cat 6 or best cable.
At today most system use the last 2 couple to provide the PoE (Power over ethernet) at the remote active network system (such as Access Point).
Now to answer to the topic, you need to see the specification of your network card, and look for the "Auto MDI-MDIX" function. If you have this function on your card, automatically the card change the state from direct to crossed to able you to use a direct cable between 2 computer. I've found this function in the ASUS P5AD2 Premium with the sk98lin.
And remember that a network cable connected directly to 2 pc can't work at 100mt such as the standard, because the network card didn't have some power to send signal. |
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nife
Tux's lil' helper
Joined: 24 Apr 2003
Posts: 87
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| Posted: Tue Feb 08, 2005 6:33 pm Post subject: |
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| AnDuR82 wrote: | Hi to all.
Before anything I've see some error
the EIA/TIA 568A standard provide this spec.
Couple 1-2 Orange =Tx Signal
Couple 3-6 Green =Rx Signal
Couple 4-5 Blu = Not actually used, for next use
Couple 7-8 Brown = Same as above
and the Gbit network card, the 10Gbps too, use only the first 2 Couple, but for better performance you need to use Cat 6 or best cable.
At today most system use the last 2 couple to provide the PoE (Power over ethernet) at the remote active network system (such as Access Point).
Now to answer to the topic, you need to see the specification of your network card, and look for the "Auto MDI-MDIX" function. If you have this function on your card, automatically the card change the state from direct to crossed to able you to use a direct cable between 2 computer. I've found this function in the ASUS P5AD2 Premium with the sk98lin.
And remember that a network cable connected directly to 2 pc can't work at 100mt such as the standard, because the network card didn't have some power to send signal. |
Actually gigabit does use all the wire pairs. Check http://www.sql-server-performance.com/jc_gigabit.asp It has a good explanation of the stuff you are looking for.
However I have read conflicting reports on whether a crossover is possible. The above web page says no. While from what I have read its possible, just a different pin out since all the pairs are used differently. I don't have two gigabit cards here or I would try it out.
Info came from:
http://www.sql-server-performance.com/jc_gigabit.asp
http://logout.sh/computers/net/gigabit/
http://www.cabling-design.com/references/pinouts/1000base_t_crossover.shtml |
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tuxmin
l33t
Joined: 24 Apr 2004
Posts: 838
Location: Heidelberg
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| Posted: Tue Feb 08, 2005 6:35 pm Post subject: |
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I thougth the Auto MDI-MDIX feature is mandatory for Gigabit NICs while it is not for slower NICs -- but I'm not 100% sure.
Alex!!!
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CriminalMastermind
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 132
Location: toronto
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| Posted: Wed Feb 09, 2005 9:01 am Post subject: |
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| nife wrote: | | However I have read conflicting reports on whether a crossover is possible |
turns out a buddy of mine is using a gigabit ethernet crossover cable and it is working at gigabit speeds. he picked it up at the computer store and it was sold as a "gigabit crossover cable". i think all the confusion is because it's not the same as a 100/10 mbit crossover cable.
| tuxmin wrote: | | I thougth the Auto MDI-MDIX feature is mandatory for Gigabit NICs while it is not for slower NICs -- but I'm not 100% sure. |
well i don't know for 100% ether, but i'd guess it is not mandatory for gigabit nics. if it was then the link i posted earlier would not exist. why would anyone go through the trouble of wiring a special crossover cable for gig-e if they didn't have to.
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