UDP and Solaris Problems
2007-12-25 8:48:00
>
> I cannot read UDP packets as reliably under Solaris 2.3 (or 2.4) as I
> could under Sunos 4.1.3.
>
> Info:
>
> 1. I have side by side sparc 10 model 41s, one running 4.1.3, the other
> 2.4 all on the same subnet. An application designed to read UDP packets
> (from a 3rd machine) runs on both machines. Each UDP packet has an
> embedded sequence number. The 4.1.3 machine does not miss a packet.
> The 2.4 machine misses packets regularily.
>
Thanks to:
sunrise!don@rambone.psi.net
Solution (sort of):
The UDP packets are the result of realtime data collection from 100
sensors located thoughout the United States. These packets funnel
through a PC for distribution. When I switched to a backup PC, the
problem went away (after 2 weeks looking for the problem elsewhere).
I still cannot explain why a solaris machine lost UDP packets, while an
identical 4.1.3 machine had no problems. And I cannot explain the
differences in PCs as they use identical hardware and software. The
problem may lie at a lower level (hardware/firmware and rev levels)
than I am willing to explore.
Suggestions received helped me understand Solaris better:
1. Use of ndd to configure /dev/tcp /dev/udp
2. Differences in 4.1.3 and solaris (udp checksums for example)
3. Use of snoop.
4. The new world of applying and testing patches.
Lesson learned:
1. Connectionless protocols like UDP are important to us. However,
applications that use UDP must be able to detect dropped packets.
Without sequence numbers embedded in each packet, I would never
have known there was a problem.
2. Critical apps need to be tested against any new patches before being
released! My test programs changed behavior after applying patches.
Bill Hiscox
------------------------------------------------------
Bill Hiscox Geomet Data Services
bhiscox@gds.com The National Lightning Detection Network
2705 E. Medina Rd #111
Tucson, AZ 85706
(602) 573-0090 voice
(602) 741-2848 fax
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