TCP fragmentation issue
ianc at microsol.iinet.net.au
Tue Jun 1 03:28:25 UTC 2004
Some of our project people have reported an issue with our product
fragmenting TCP packets destined to another machine when the length of
the packet is between 100 and 202 bytes in length.
TCP packets of larger sizes are sent through unfragmented.
We are using RTEMS 4.5.0 for our product with 100MBit Ethernet. The max
MTU is not set in our stack (set to 0 so defaults to 1500) and it is not
set to anything other than default on the Windows machine it is talking
to. They have tried various different machines to with the same results.
This in itself is not a problem, but a commercial package on the windows
machine, has a problem if the packet is fragmented which is causing
issues. We have other systems running with no problems, so they have
asked if I can look into it. They even checked it with another package
that works, and the checked the raw packet log and saw that packets of
between 100 and 202 bytes were fragmented, so this particular package is
not effecting the behaviour.
I had a quick look in the mail archives, and nothing turned up.
Before I start a proper investigation, has anyone seen this sort of
behaviour before in RTEMS and have an explanation about why it is happening?
I look forward to your responses.
Microsol (Aust) Lty Ltd.
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