I am taught that Twisted Pair cables are twisted to cancel interference. Now, I have a CAT-5e crossed over cable of approximately 2 M in length. I removed the cable's cover and untwisted the wires. Still I can see no difference in performance of my network of two computers. Why? If I want to introduce the errors how can I do so? Also is there a way to check Data Link Layer errors using some command?
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.. approximately 2 M in length. I removed the cable's cover and untwisted the wires. Still I can see no difference in performance of my network of two computers. Why?
You probably don't have errors because of the relatively short length of the cable. The longer the cable length, the more attenuation of the signal intended signal and greater build-up of undesirable signal. The maximum spec'd distance of Ethernet is 100 meters, so at 2% of that, you probably haven't a sufficiently bad enough cable.
Using a longer cable, introducing an electromagnetic source of interference through inductance, or using a lousier cable (CAT 3 / phone cord) may cause more errors.
Errors are detected using a CRC32 of the ethernet frame. On Linux, you should be able to see any errors detected at this level by using
You'll need longer cables. I've had many problems (mostly packet loss) with wrongly crossed cat 5 cables (direct 1 to 1 wiring scheme and not any one of standarts like http://www.washington.edu/lst/help/computing_fundamentals/networking/schemes) with lenght about 30-50 meters. Try this)