Phantom CAT5 Wiring Problems ?

We have problems sending out data (emails with attachments, ftp transfers etc...) from our ethernet network. We have full download speeds of over 5mbps, but our upload speeds are >100kbps.

We are receiving our internet connection from another building in the commercial center we are in. We've isolated the problem to a CAT5 cable running in a metal conduit under the parking lot. We isolated this by testing the speed at various points in the network. Computers before these cables run fine, but all of them after have these slow upload speeds.

The strange part is that there are five (5) CAT 5's ran through that conduit, and all of them are having the same strange problem. We only use one, but tested them all.

Do you know what could cause this kind of data loss, but only in one direction? I was thinking the conduit filled up with water, but why doesn't it affect the speed both ways?

Thanks in advance for any insight you can offer...


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Assuming the lengths are within CAT5 specs (90 meters?), I bet the same guy pinned all 5 cables the same way; wrong and/or there is some common fault in the tools you are using to test all 5 cables.

"netstat -e" will report types of packet errors and on any small network like yours the errors and discards should be zero or single digits unless the system in question has been in operation for years. Run it on all the computers and you might learn something.

There is no magic solution here for someone with no network analyzers, I'd attack it by getting two laptops that have 10/00 NICs. Make sure they work together when in the same room and connected by nothing but a short (factory made) crossover cable. Test two short patch cables and make sure *they* work, too.

do an ipconif/all on each computer and make sure both ends of each link are detecting the same settings.

I'll look for others for a recommendation for good basic Windows software to create artificial traffic between the two laptop and to show results. When the laptops are connected by a short cable get a baseline data rate number in both directions.

Then carry one laptop and a patch cable to the other location. use the crossover to connect a laptop at one end. Rerun the same test.

Don't have any other cables or devices in the circuit when you test.

If the test *does* show the cables are bad, repunching the 110 blocks is the next step. If the cables have RJ45 plugs, instead, I'd make this the first thing I'd do. If the cables are stranded (look at the jacket), IMO, you're screwed. Use the existing cable as a pull cord for CAT5 solid cable and then install 110 termination.

Reply to
Al Dykes wrote in part:

This is normal behaviour for networks with a cable or ASDL uplink. But I'm guessing you've got a T-1 or T-3.

Hazardous to equipmen since nearby lightening strikes will create a gound potential difference between the different buildings ground-stakes.

If it isn't asymmetric network (and other stations seem to confirm it is not), then the symptoms are prefectly consistant with a split pair. One direction is fine, the other crappy.

Find the ends of the cable outside the conduit. Are they plugs? Or are they jacks (female)? Check the color code. If they are plugs, look carefully through the plastic and read off the colors.

If these have been field crimped by an inexpert person, it is likely they were improperly arranged, splitting a pair. Electrons may be color blind, but they know who their dance [twist] partners are. The correct crimpings are non-intuitive.

-- Robert

Reply to
Robert Redelmeier

mycomputer > properties > device manager > network adapter > your lan card > select properties > select from link speed and duplex > change the value to Auto full duplex.

see if that work by changing value



Reply to
Dan Chatha

from auto to full duplex

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