Does the switch offer you a counter of bad ethernet frames?
You can get the info for the PC end from ethtool: mephi@mephi-server:~$ sudo ethtool -S eth0 NIC statistics: tx_packets: 0 rx_packets: 0 tx_errors: 0 rx_errors: 0 rx_missed: 0 align_errors: 0 tx_single_collisions: 0 tx_multi_collisions: 0 unicast: 0 broadcast: 0 multicast: 0 tx_aborted: 0 tx_underrun: 0
specifically you're looking for rx_errors, the other end (the switch) will need to report on it's rx_errors
If your switch can't do that you can always connect two PCs back to back with the cable.
To test, you'll need to spam a whole load of data over the cable using something like iPerf and then check those counters. BTW, There's no way (that I know of) to reset those counters (on linux, a lot of switches can) except by restarting the PC.
Regards,
Matt
-----Original Message----- From: main-bounces@lists.alug.org.uk [mailto:main-bounces@lists.alug.org.uk] On Behalf Of Chris Green Sent: 04 December 2011 12:48 To: main@lists.alug.org.uk Subject: Re: [ALUG] How to test if a cat5 (or cat6) is working as well as it should?
On Sun, Dec 04, 2011 at 12:13:02PM +0000, Srdjan Todorovic wrote:
On 4 December 2011 11:55, Chris Green cl@isbd.net wrote:
I have a number of quite long (i.e. 30 metres or more) cat5e cables strung about the place and would like to test how 'clean' they are.
It's easy enough to test their basic integrity (i.e. if all 8 wires are correctly connected) and I have done that. However I'd like to see if they are actually good enough to provide maximum performance when running gigabit.
You could perhaps run iperf with each cable in turn between 2 machines and no switches, and compare any performance differences?
I have no idea what proper quality control tests cable manufacturers do.
I'm not so worried about the basic quality of the cable but it has been roughly handled in places and the connections may not be perfect.
-- Chris Green
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