Another Ethernet problem for Thomas :)
Thomas.Doerfler at imd-systems.de
Wed Jan 30 06:24:18 CST 2008
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Leon Pollak schrieb:
Here is the simple solution:
Today we have detected some spurious UDP packets arriving on our
firewall. They all had a counter value of ZERO and came from the domain
"plris.com". So now I know how they were sent. Leon, if you like, I can
send them back as attachment in a separate email :-)
Ok, no more kidding. ;-)
So now you got me, I have no idea what can actually be the reason for
this (Oh, just a hint, it is a software problem).
What I would do:
- - check, that the statistics counters of the driver are coded properly,
so they really count all packets sent, all tx errors etc.
- - compare the number of packets sent with the number of packets tcpdump
can count (using the rtems_bsdnet_show_if_stats() function)
additionally you might want to use the following functions to get more
- - check, that no mbufs are lost over time:
- - Just a guess (no, not again!): Does the packet loss only occur, when
you have waited some minutes after the last transmission? maybe some
switch/arp cache/xxx has lost routing information then and needs one
packet to get things working again?
| Hello, all and Thomas especially! :)
| The last time Thomas's help was so effective, that I hope he knows the
| decision of my (I hope the last) today's problem:
| Using netdemo application I send UDP packets to the Linux box with nc -lu
| waiting. I press 'u' in console and it starts sending UDP packets.
| Everything works fine, but approximately once per 7-10 restarts I see
| very first packet does not arrive!
| I put counter into the packets and can see its '0' value is missed rarely
| after restart.
| I run tcpdump to check and also saw when this occurs, that the first
| missed in the tcpdump too.
| What can it be and how can I debug the situation?
| [Each time I put breakpoint in the driver at buffer sending the
| occurs.:( But there are other packets too...]
| Thanks a lot ahead.
IMD Ingenieurbuero fuer Microcomputertechnik
Thomas Doerfler Herbststrasse 8
D-82178 Puchheim Germany
email: Thomas.Doerfler at imd-systems.de
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