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Standard User Banger
(eat-sleep-adslguide) Wed 07-Dec-11 02:24:26
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Is this right?


[link to this post]
 
According to this page 1000 Base T ethernet is auto sensing and irrespective of plug wiring should auto negotiate a connection if both sockets are 1000 base t capable.

Now I have just ordered a Billion 7800 which has gigabit MDI/MDI-X ports for LAN and two of my computers, one upstairs one downstairs, have gigabit ports too.

The router will be upstairs so dont see a problem with the computer upstairs but the one downstairs is hard wired for 100 base t crossover with Cat 5 shielded twisted cable. Computer downstairs also has gigabit port so will the router negotiate 1000 base t with downstairs or am I looking and plug rewiring. Originally the ethernet connected the two computers crossover at 100 base t. Do I need to straighten out the crossover or is it as the wiki article says immaterial? Have tried computer to computer but they only connect at 100 base t.

Tim
www.vivaciti.net & freenetname
recapped ST546v6 on 24 Meg Variety LLU
My Broadband Speed Test
Standard User AEP
(eat-sleep-adslguide) Wed 07-Dec-11 07:16:25
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Re: Is this right?


[re: Banger] [link to this post]
 
You need a Cat 5e (or Cat 6) cable. Cat 5 can't do Gigabit.

Almost all routers/switches are autosensing, irrespective of speed.
Standard User camieabz
(sensei) Wed 07-Dec-11 08:01:13
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Re: Is this right?


[re: Banger] [link to this post]
 
Assuming the CAT5 plugs are terminated properly, you can probably get gigabit* up to 100 mtrs. The shielded cable ought to reduce the interference that CAT5e generally reduces or eliminates. If it's a case of using existing cables, try it. If buying new cable, I would suggest minimum of CAT5e. I've got CAT6 from my master socket to my extension in the computer room. Only thing is, the gauge of it is slightly heavier, so you really need CAT6-specific plugs/IDC points.

Also good to get solid cable, as opposed to stranded.

* Bear in mind all nodes in the systems have to be gigabit capable.

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Standard User AEP
(eat-sleep-adslguide) Wed 07-Dec-11 08:11:09
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Re: Is this right?


[re: camieabz] [link to this post]
 
Well, I can't get a Cat 5e cable to run Gigabit over 3m, let alone 100. This reference, amongst many others, confirms my belief that you need Cat 5e or above. For the cost of a cable it's surely worth a try.
Standard User mixt
(experienced) Wed 07-Dec-11 08:30:14
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Re: Is this right?


[re: AEP] [link to this post]
 
I thought CAT5 can do gigabit over short distances?

As I understand it, there is no difference in the wiring. The difference between all these standards is the quality of the cable, and specifically, the number of twists they manage to cram into the cable per unit length to eliminate cross talk between the twisted pairs. The more twists, the more this eliminates the cross talk, and so the higher the signal rate that can be achieved on the pairs.

That's how I thought it works anyway.

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Standard User AEP
(eat-sleep-adslguide) Wed 07-Dec-11 08:55:30
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Re: Is this right?


[re: mixt] [link to this post]
 
I can only speak from experience. I have tried using 3m Cat 5 cables in a Gigabit setup and they do not work. Substitute Cat 5e and they work fine. As for the 100m that was suggested - in my understanding that is the maximum length for 10/100 networking, let alone 1000.

The OP has a problem, most likely either because he is using a crossover cable (I very much doubt that is the problem) or because he is using Cat 5. In either case he needs a new cable (which will cost a couple of pounds). Pragmatism suggests that he buys a Cat 5e one.
Standard User Banger
(eat-sleep-adslguide) Wed 07-Dec-11 09:10:55
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Re: Is this right?


[re: AEP] [link to this post]
 
Problem is the Cat 5 is under floors through walls, etc and is about 15 metres. Works fine for 100 base t and re-terminating isn't a problem just wondering if it's because it's crossover and not straight. Even got shielded plugs at the time and if I remember correctly the actual cable is cat 5a.

Tim
www.vivaciti.net & freenetname
recapped ST546v6 on 24 Meg Variety LLU
My Broadband Speed Test
Standard User AEP
(eat-sleep-adslguide) Wed 07-Dec-11 09:22:36
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Re: Is this right?


[re: Banger] [link to this post]
 
Well, if you have the ability to reterminate the cable then you can convert it from crossover to straight (which is probably the safest option even if your equipment is auto-sensing). You can also try the other suggestions here to maximize your chances with your cable. Although all the reputable sources that I can find say you need Cat 5e I can appreciate that all installations are different and you may be lucky. Experiment and see what you get.

But if your current cable doesn't work, cant you just use it to pull Cat 5e (or even Cat 6) cable through? (Or is it physically attached with cable clips or suchlike?)
Standard User Banger
(eat-sleep-adslguide) Wed 07-Dec-11 09:29:24
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Re: Is this right?


[re: AEP] [link to this post]
 
Yes you guessed it lots of cable clips and one part through a sealed pipe box with wallpaper on it. I'm sure when I bought it the cable was shielded 5a which I think was the first generation of 5e and is capable of gigabit but having trouble tracking down specs for 5a.

Tim
www.vivaciti.net & freenetname
recapped ST546v6 on 24 Meg Variety LLU
My Broadband Speed Test
Standard User AEP
(eat-sleep-adslguide) Wed 07-Dec-11 09:50:28
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Re: Is this right?


[re: Banger] [link to this post]
 
I can appreciate your problem.

But, as I understand your OP, you tried computer to computer and it only worked at 100. If this is correct then your problem cannot be because it is a crossover cable (else it just wouldn't work). BTW, the manual for the Billion router says that all the ethernet ports are autosensing, so crossover or not shouldn't be a problem.

If the situation is as I understand it then your problem has to be with the cable (or - less likely - one of the computers will not function at 1000 for some reason). In any case it may be worth reterminating both ends, following Camie's suggestions, and then trying again. But, should that fail, I'm not sure what you can do other than replacing the cable.
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