Cabling Question

[x_jose_x]

Hello,

I recently installed a new run of Cat6 in my home, from my router to the living room. In the living room I put in an outlet for the network cable.

At first I assumed I could put a RJ45 end on the Cat6 cable. However, the cable is solid (not stranded), and the RJ45 plugs I bought don't fit on the cable. I considered my options, such as a patch panel. I decided against that, and just for a quick and dirty solution, bought another keystone, and wired that to the other end of the cable.

I tested the cable, and the cable tested out fine. However, my desktop would not show any link on the cable. I test it again. Cable is good.

At this point my wife suggests I try a different computer. Did I listen? Of course not. I keep testing the cable, trying different patch cables, re-installing the NIC driver, etc. I waste a lot of time.

I eventually do try a different computer. I hooked my laptop to the cable, and it connected immediately. I should have listened to my wife in the first place.

While I was trying to figure out why my desktop would not connect, one thing I tried was to wire the main cable run (between the keystones) as a cross over. When I hooked my laptop to the cable and it worked, the cable was wired as a cross over. I have since put a switch in the living room, and have both the desktop and the laptop are wired up, and even the desktop connects (the desktop is wired to the switch with a cat5e cable).


Now for my actual questions:
1. It is coincidence that the main cable run is wired as a cross over. However, it works. Should I have wired the main run between the keystones as a cross over from the start?

2. Since I know the NIC on my desktop is good (as it is connects when plugged into the switch), and I know the cable run is good, as I can hook a cat6 patch cable between the outlet and the laptop, and it works, what are some possible explanations as to why the desktop wont connect over the cat6 patch cable?

Mobo: Asus M3A79-T Deluxe, NIC controller: Marvell Yukon 88E8056 PCI-E Gigabit Ethernet

Thanks!
-Jose

 

[thiggins]

Your cable runs should generally not be wired as crossovers.

One computer worked and the other didn't probably because the one that didn't had a NIC that didn't support auto MDI/X and the one that did, did.
The switch you're using also probably supports auto MDI/X.

 

[x_jose_x]

Hello Tim,

Thank you for the reply. I did look up what MDI/X was. However, I did have main run wired as a straight through at first. I only tested cross over as a process of elimination to see why the desktop did not connect. MDI/X would explain why the other devices did connect.

I changed the main run back to straight through.

I tested the desktop again with just a cat6 cable between the wall outlet and the NIC. No connection.

I tested the desktop with a cat6 cable between the switch and the NIC, no connection.

I tested the desktop with a cat5e cable between the wall and NIC, it connected. (It also connects with the cat5e between the switch and the NIC.)

Through the above process of elimination, it would appear that the desktop NIC can't connect over a cat6 cable.

Is it possible that some NICs are not compatible with cat6 cable?

Thanks,
Jose

 

[thiggins]

Is it possible that some NICs are not compatible with cat6 cable?

Unlikely. But you could test by using a CAT6 patch cord to connect the two computers in question.

You don't need CAT6 anyway for Gigabit. 5e is fine.

Given the solid cable, perhaps there is an intermittent connection problem.

 

[x_jose_x]

I see. I'll just have to use the cat5e patch for the desktop. Thanks!

 

[YeOldeStonecat]

The Marvell NICs can be surprisingly..."picky". They are not very well liked NICs. Asus has been my favorite motherboard brand for a long time...I just wish they'd stop using Marvells.

The need for crossover cables has pretty much gone the way of the floppy drive, 9 pin serial port, ISA cards, and the dodo bird....extinct. Auto MDI-X has been adopted in the gigabit standard. So if at least 1x device on a run has a gibabit NIC or port..it'll figure out which way to go.

So I suspect that the wiring is a little "off"..and the Marvell isn't being tolerant of it. What if you.....go into the properties of your Marvell NIC..and manually set it to slower speeds? Try setting it to 10 megs...1/2 duplex..if good...bump up to full duplex...if good..bump up to 100 megs 1/2 duplex...if good..full duplex. If it'll only hang at 10 megs ..good enough for internet. Or work on your wiring techniques some more til it'll run at faster speeds.