[c-nsp] 3550 Port Fault that only forwards small packets

[Kevin.X.White at corusgroup.com]

We use 3550-FX for fibre distribution and have had a couple of instances
whe we've been investigating user complaints of a sudden onset of poor
perfomance and found a port which has no errors of any kind will pass pings
<500-1000 (btw the failure point is not around 1500) but no larger, also
telnet sessions would intermittantly stutter if a long output say show tech
was used.

On one occasion, after moving the feed onto another port ( all working
fine) and hanging a 2940 on the faulty port to do some testing I was
baffled by the fact that an extended ping of 1K from a switch through this
port would fail but a 1K DOS ping from a PC on the same box I was pinging
from would succeed!

The only measurable symptom of the fault is RX drops on the 2950 that was
connected to the faulty port but I have too many of those to monitor with
Solarwinds!

I've now had this on 3 of 3550s along with hard port failures so we are
moving to 3560s with m/c racks :-(  2 down 10 to go!

Suggestions or comments welcomed.


Kevin
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