[Gllug] Electrical interferense?

[Rich Walker]

"Henrik Morsing" <henrik at morsing.cc> writes:

>> "Henrik Morsing" <henrik at morsing.cc> writes:
>>
>> I have seen this with machines occasionally.
>>
>> You *are* using STP rather than UTP for your network cables?
>
> No. I don't think my switches supports it.

I'm not sure they need to. The simple fact of the metal foil layer
connected to chassis ground on the PC's would be helpful

> Also wouldn't it show up as errors?

The bad network card problem doesn't - just things like 3-day boot-over-NFS...


>> Also, try ping -f between two machines - I've seen network cards that
>> worked perfectly for a ping -f's b, but fail for b ping -f's a.
>
> How exactly do you mean? a and b?


Different machines on your network. For example, when esk was doing
this, I did

root at thoth# ping -f esk

and

root at esk# ping -f thoth

On a good network connection, you should see one or two dots. If there
is a problem, you will see a lot of dots, and the line will get longer.
ping lin-pc:/home/rw/papers# ping -f thoth
PING thoth (10.1.1.11): 56 data bytes
..
--- thoth ping statistics ---
3678 packets transmitted, 3676 packets received, 0% packet loss
round-trip min/avg/max = 0.0/0.1/21.3 ms
lin-pc:/home/rw/papers# 


thoth:~# ping -f lin-pc
PING lin-pc (10.1.1.151) 56(84) bytes of data.
 
--- lin-pc ping statistics ---
5169 packets transmitted, 5169 received, 0% packet loss, time 903ms
rtt min/avg/max/mdev = 0.076/0.089/10.776/0.149 ms, ipg/ewma 0.174/0.087 ms
thoth:~# 



(I interrupted them with CTRL-C)

cheers, Rich.

> ---
> Henrik Morsing
> henrik at morsing.cc
>
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-- 
rich walker         |  Shadow Robot Company | rw at shadow.org.uk
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