UDP packet not sent

[Rolf Schroedter]

I know, that UDP itself is not reliable, it's not guarantied
that the sent packet will be received at the other side.
But I expect that at least the UDP packet is *send out*,
when sendto(..,MSG_WAITALL,..) returns success.

Running RTEMS 4.6b with the open_eth driver at the LEON-SPARC.
The application receives requests and acknowledges them by
sending data.
E.g. it sends
	60 packets x 1040 bytes
	1 packet x N bytes
	1 packet x 100 bytes

All calls result=sendto(buf, size,MSG_WAITALL,..) return result=size.
However snooping with ethereal shows that
	if (N >= 966) then all packets are sent
	if (N <= 964) then this packet is *not sent*

The result is stable. In all cases the following last 100 byte
packet is sent.

Any ideas why and where the packet is swallowed ?
Thanks,
Rolf.

---------------------------------------------------------------
Rolf Schroedter
German Aerospace Center
Institute of Space Sensor Technology and Planetary Exploration
D-12489 Berlin, Rutherfordstrasse 2
Tel/Fax:  (+49) (30) 67055-416/384
Email:    Rolf.Schroedter at dlr.de