Re: [tlug] test of ethernet cable length

[Lars Kotthoff <lists@example.com>]

> recently I have seen a computer with a bios, that could test the length of an
> ethernet cable connected to it's NIC. So I came to the idea,
> that perhaps some smart program in linux could have the same
> functionality.  

That was most likely using a special cable/NIC/...
The speed of signals through a network cable is near the speed of light, i.e.
even if your clock had a resolution of a microsecond it would only be able to
measure the length of the cable in multiples of 100m -- assuming that you're
able to pinpoint exactly how long it takes the signal to go through the cable.
Even when the firmware of the other NIC replies directly to your ping packet or
whatever you're sending it's rather unlikely that you'll be able to say exactly
how much time it spent processing it (unless you're using specialised
hardware).

Lars