[Soekris] Strange problem with net4801
horst.laschinsky at physik.uni-erlangen.de
Wed Jan 19 01:55:20 UTC 2005
Clemens Zauner wrote:
> Do not use cables with shielding on both sides. either unshielded,
> or shield connected to ground on only one end.
What the f...? That worked! Can anyone explain me why? Up to now,
I always thought the sole reason for the existance of common grounds
was to _avoid_ disturbances???
But anyway, this still does not explain the effect as such.
> > 1) Why is the transfer rate so small at all? Maybe interrupt / DMA
> > conflicts?
> The 4801 has a 233MHz CPU. you will experience some limitations here.
Of course I may. But is a 233MHz CPU really so slow, that it cannot
transfer data at 100MBit (or at least 40-50 MBit) 3des encrypted?
> Usually not, But as you are running 1 stream you will see some effects.
> e.g. Collisions are unlikely if you do only tftf (udp-bound protocol);
> as the server sends out udp frames and the clients ACKs them (and
> the server does not send any more until the ACK is received => the medium
> is idle).
Yes, this would result in packet drops or other errors. But what
I got was a "carrier error", and that means that the NIC lost the
link beat. And I simply cannot explain how the ssh protocol could
> > 3) Why does 2) only apply to outbound connections?
> One side is sending ACKs (small packets), the other data (large).
Yes, but if I transmit data from the PC to the Soekris it would be
just the other way round. So the effect should also appear but
Anyway, thank you very much!
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