2 Problems regarding cables.

[Maleficus]

First problem: I have a couple of computers i am trying to get connected, first is my computer that is obviously connected. Second is a computer in the living room which absolutely will not work with this 35 foot cable I have. No problem i thought it must be the cable, so i moved the computer into my room and plugged it in with a 6 foot cable i have laying around, poof it works. I get a new 35 foot cable for the computer move it back and plug it in, nothing. I then plug in that cable thinking no way 2 cables wont work into my computer and it works. I don't know what to do about this, i have tried multiple ports on the router all with the same results. Cable works just not for that computer, other shorter cables work but they won't reach into the living room.

Second problem: When i connect cross-over cables from comp to comp i was getting a transfer rate of a whoppin 7k! I don't know what the problem is here either, i tried multiple cables to no avail.


Any help is appreciated, TIA.

 

[GoldChain]

It could be a faulty NIC. You should be able to use up to 300ft cables with no problems.

Having said that, there's something you might want to check first. There is a little known flaw in the ethernet autodetection. This flaw doesn't affect speed, but it affects duplex. Seems like such a small thing, but could be the explanation for your 7K when using your crossover. Here's the scoop:

1) When the duplex autodetection fails, it defaults to half duplex.
2) Duplex autodetection does NOT work unless both ends of a connection are on "auto".

So, if you have one NIC set to auto, and the other forced to (say) 100-Full, the card on auto will fail to half-duplex and you WILL see a majorly slow connection (because of the duplex mismatch). I see this kind of thing all the time, everyday.......

Since virtually ALL switches and routers w/built-in switches are always set to auto (some you can manually change but even those default to auto), you're best bet is to always leave your PC NIC set to auto. (This doesn't really apply to hubs as they are half-duplex only and worse-case your autodetect will fail to half-duplex and you're okay anyway... just never set to Full duplex when using a hub).

It's funny because I recall many of my friends, when first getting a 100M switch, forcing their PCs to 100-Full since the switch could do full-duplex. In reality, they were causing the ports on the switch to fail to half-duplex mode, and killing their performance. LOL

I would simply try using those 35 foot cables on another PC close-by. If it works fine, then you're NIC is the most likely culprit.

GoldChain

 

[DannyBoy]

Isnt 100 metres the max length of a patch cable?

 

[GoldChain]

Originally posted by: DannyBoy
Isnt 100 metres the max length of a patch cable?[/i]

Isn't 100 metres just over 300ft?

But yes, you should be able to run up to 100m/300ft for 10/100/1000Mbps ethernet.

GoldChain

 

[nutxo]

Originally posted by: DannyBoy
Isnt 100 metres the max length of a patch cable?

bah, we americans prefer archaic units of measurement

 

[gunrunnerjohn]

If it works fine with a 6' cable and fails with a 35' cable, I'd be looking very closely at the construction of the cables.

 

[ScottMac]

The 100 meter spec does not apply to patch cables. BY THE SPEC the longest a patch cable should be is FIVE METERS (~15 feet).

The 100 meter spec applys to 90 meters of standing solid core cable with 5 meters of patch at each end (100 meters total).

Patch cables use stranded conductors, which have more loss than solid conductors (at least in this case).

All of the above assumes proper termination (correct components correctly installed).



FWIW

Scott

 

[DannyBoy]

Originally posted by: GoldChain

Originally posted by: DannyBoy
Isnt 100 metres the max length of a patch cable?[/i]

Isn't 100 metres just over 300ft?

But yes, you should be able to run up to 100m/300ft for 10/100/1000Mbps ethernet.

GoldChain

Bah I misread what was typed, I thought you put 300 metres lol!

My bad

 

[Maleficus]

Originally posted by: gunrunnerjohn
If it works fine with a 6' cable and fails with a 35' cable, I'd be looking very closely at the construction of the cables.

I tried 2 different 35' cables and they work on my machine but not on the other :\

 

[gunrunnerjohn]

If it's not the cables, it's something odd about the NIC's. 35 foot cables, properly constructed, should be no issue.

 

[martind1]

perhaps you are running the 35 ft cable by somethign that is causign interference with the transmission?

any suspects? speakers, furnaces, power cables, anything?


try runnign it an alternate way.



this all fails, then i blame your NIC.