Re: CRC Errors on GigE.


Rick Jones wrote:
nkarkhan <nkarkhan@xxxxxxxxx> wrote:
One end station sends a packet, the other side responds back in
under 800 usecs. if any packet is lost, the machine keels over.

That the machine would keel-over (which I take to mean "dies") if any
packet is lost seems rather brittle... It is one thing to have "the
machine" have to go through some sort of involved recovery procedure
(short of reinitialization), but to have it keel-over...


"Keel over" doesnt mean die, but it means that customer is pissed off
(pretty close to "die" i guess).
The 1 packet missed and its a disaster design comes from limiting the
machines top speed, if i reduce the machines top speed, i can tolerate
2 -3 -4 packets being dropped. But I do want to go as fast as safely
possible.

Plus, I was expecting bit blasting noise to come from sources like
Motors starting, electric spikes, sunspots etc. All of which last for
10+ milliseconds.
So the idea was that if I miss one packet, I would most probably lose
the next 10-20 msecs of packets too. I cannot reduce the speed to allow
for 10 missed packets anyways, so why not just design for no losses and
add sheilding to keep the noise out.
b.t.w none of these noise sources are present in the current crc error
scenario.

.