Gigabit Network, NOT running at gigabit speeds!

[rspierz]

This is a really tricky issue ... basically we have a TP-LINK router that is confirmed gigabit with 4 cables to which are all cat5e cables. The cable run isnt more then 20 ft for each cable either. I have confirmed that all the pairs are working in my cable and when I set my computer to gigabit only, there is no connection. Basically our network is modem, to TP-LINK, to 2 cables that go to access points/routers which are also gigabit and the other 2 cables go directly to PCs. I have used the T568A wiring.

Any help would be greatly appreciated, as we have tried multiple routers and still no gigabit shows up only 10/100.

 

[GregN]

Are you positive the PCs have Gigabit NICs in them, indicator lights on the PC Cards?

TP-Link to router/AP you are not seeing any LED indication of 1000Mbs?

 

[thiggins]

What happens if you leave your NIC to auto-negotiate?

 

[rspierz]

Im positive all NICs are gigabit we all have new laptops with Intel(R) 82579LM Gigabit Network Connection. There are indicator lights on the NIC. I have it set to auto-negotiate right now and it gives us all 100mbps. When set to gigabit only nothing comes up, doesnt even try to get a DHCP address. the TP-LINK doesnt have different lights to tell you if its gigabit or not (i think) but when we were configuring the router we plugged it into a small 3ft 5e cable and it said gigabit.

My thoughts are that it could be the cable. the cable that is run says its Cat 6e and its got solid twisted pairs with the plastic separator in the middle. It just doesnt make sense. Do some routers only read the B cabling schematic?

In addition I just tried plugging only my cable that is straight to my PC with all pairs confirmed working, still no gigabit link, ARGH!

 

[thiggins]

what model TP Link router are you using?

 

[rspierz]

Heres a link to the router: http://www.tp-link.com/en/products/details/?categoryid=238&model=TL-WR1043NDz

We are running DD-WRT on it though if that helps

 

[thiggins]

Maybe DD-WRT is the problem?

 

[GregN]

Any help would be greatly appreciated, as we have tried multiple routers and still no gigabit shows up only 10/100.

You have tried other gigabit non DD-WRT routers?

 

[claykin]

Sounds like a cabling issue. You mentioned you wired using 586A. Make 100% certain that both ends of each run are following the same standard (A or B). There is no issue at all using 586A wiring standard with your equipment. Only issue comes into play when one end of link is wired A and other end wired B.

Try this driver from Intel. It may include a cable link tester as well.

http://downloadcenter.intel.com/Det...g&OSVersion=Windows 7*&DownloadType= Drivers

 

[GregN]

Sounds like a cabling issue. You mentioned you wired using 586A. Make 100% certain that both ends of each run are following the same standard (A or B). There is no issue at all using 586A wiring standard with your equipment. Only issue comes into play when one end of link is wired A and other end wired B.

Try this driver from Intel. It may include a cable link tester as well.

http://downloadcenter.intel.com/Det...g&OSVersion=Windows 7*&DownloadType= Drivers

Would the cable fail or exhibit the lower link speed?

 

[jdabbs]

Would the cable fail or exhibit the lower link speed?

If the cable has only two pairs connected (1-2, 3-6) it will downgrade to Fast Ethernet. Gigabit needs all four pairs to operate, so it is a surefire way to discover that the person handling your building's internal wiring cut a few corners.

Cheap cable checkers confirm continuity. Cruddy crimps comply completely.

I'd verify the computer works with Gigabit manually specified. A gigabit router and known good cable would suffice. If that works, and since the router has already been swapped, I'd suspect the cable run.

 

[rspierz]

We have tried other non DD-WRT routers and still the same issue. My cable is wired for 586A and I am 100% certain both ends are the same standard. I know this because I have a cable tester and all the pairs came up on it as connected. As I previously mentioned that I tried it with only my cable plugged into the router and still no gigabit, I know that some of the other cables do not have the full 8 pairs working but the router should auto-negotiate that anyways. I was thinking because we ran our cables through the ducts, perhaps there is some kind of interference that limits the signal strength? we are using UTP cable.

I just ran the intel diagnostic thing for link speed. It says the cable cannot support a higher speed then 100mbps. It showed no problems in the connection, cable or hardware.

 

[thiggins]

Sorry for the obvious questions.

1) Have you confirmed that connecting directly to the router with off-the-shelf patch cables will give you a proper link?

2) Are you sure that you connected the proper-colored wires in the cables to the proper terminals on the jacks. A simple cable checker will show continuity, but not whether the connections are made with proper wire pairs.

 

[rspierz]

1) Yes I have, however the cables I tried were all T568B so im going to try a T568A right now. never mind it worked with T568A too.

2) Yes, but also the cable checker checks each pair so if one pair was not in the right spot you would not see all 8 pairs light up.

 

[jdabbs]

2) Yes, but also the cable checker checks each pair so if one pair was not in the right spot you would not see all 8 pairs light up.

Not necessarily. If you transposed 5(white-blue) and 6(green) on both ends, you'd still show all pairs connected, while leaving the connection extremely susceptible to interference. You place undue confidence in the abilities of the cable tester. They are great for indicating that a cable is bad, but less so for determining if a cable is any good. Simple mistakes, like untwisting a pair too far during the crimping process, are unlikely to be picked up by all but high-end testers.

At this point I would be more concerned about getting Gigabit Ethernet working at least once instead of troubleshooting. It should take you less than five minutes to use the spare gigabit router and off the shelf cable you have already stated to have on hand.

If that doesn't work, start PC troubleshooting.
If it does, swap the TP-Link router with the spare.

If that works, the router is suspect.
If that doesn't work, something is wrong with the cable run. Keep the spare router in place and start cable troubleshooting.
​

 

[rspierz]

I see what you mean. I am certain I have cabled corrected as i did it twice. however from all your help I see that the problem is definitely the cable as my PC is fine and so is the router.

I will try re-cabling another cable with T568B. Do you think running cable inside a duct system could provide enough interference to prevent a gigabit link speed?

 

[jdabbs]

Running it near a fluorescent light ballast can cause problems, as can sharp turns. With what I assume is a 20 ft, plug to plug, single cable run, the crimps stand out as the probable fault.

 

[rspierz]

You might be right. There probably are a couple of sharp turns as well so ill look into it. Anyways thank you very much for the help. I will post an update if I find the root cause.

 

[claykin]

For 20' runs the problem is more likely termination issues or damaged cable. If you have interference at 20' either the interference is severe or the cable quality is suspect.

 

[rspierz]

For 20' runs the problem is more likely termination issues or damaged cable. If you have interference at 20' either the interference is severe or the cable quality is suspect.

Yeah i'm almost certain its the quality of the cable. It says 6e on the cable but it seems fragile to the touch (aka when you bend the cable close to 90 you see white. like its about to tear. It just boggles me how it is solid wire but perhaps it is not a solid grade of copper.