Its not a problem with timing as I first expected. Instead is seems to be a problem with acknowledgements. By listening to the channel I saw 3 retransmissions of all the ping packages. Strange because the smaller once seem to be received by both ends. But looking in "event void BareSend.sendDone(message_t *msg, error_t error)" in IPDispatchP and checking if the packages where acked or not none of them were. Resulting in 3 retransmissions. The packages that were not fragmented were received ok, even tho multiple copies were sent and received. But the once that needed fragmentation were not sent completely because after the first fragmentation the PacketLink layer indicated that the first fragment was not received and the complete packet was dropped. By removing the PacketLink.wasDelivered if statement fragmentation started to work and by only trying to send one copy speeded up transmissions.
So one question is; Do you use any define for the RF212 chip that made fragmentation work for you? Because if Im using the same code as you fragmentation should work for me to without changes. But now I'm atleast on the same level as you. I can ping OK up to around 400 bytes after that I'm experiencing the same behaviour as you are. Hopefully Ill have some time over for this next week, but for now I will atleast manage to send packages that I need. /Henrik 2011/9/2 Henrik Mäkitaavola <henrik.makitaav...@gmail.com> > Ok, now I have a few hours over for this. My first thought is some kind of > timing issue. And this is maybe true considering that you are experiencing > the same problem but with larger packages. Maybe your mote is faster to > handle incoming packages but cant keep up when they get bigger than a > certain size. Because your mote seems to be able to reassemble smaller > packages so the code should atleast work with packages up to the same size > as you. If the problem doesn't lie with memory handling or something like > that. Ill do some test now and inform you with the results. > > /Henrik > > > 2011/9/2 Johny Mattsson <jmatts...@dius.com.au> > >> Hello Henrik, >> >> I hadn't noticed any issues with our systems here, but we try to keep the >> packet sizes down. I've run a few ping tests here, and there is definitely >> something odd happening. If I for example ping with 400 bytes of data, I >> reliably only get four (4) replies before it stops. *However*, if I then >> send a small(ish) ping it responds again, and it's once again possible to >> ping with 400 bytes. It doesn't seem deterministic whether I get another >> four 400-byte pings after that or not though. So to answer your question: >> yes, but apparently nowhere near as bad as you're seeing! >> >> It would be great if someone with a non-rf2xx radio could check if they >> too see this behavior. Anyone? :) >> >> Cheers, >> /Johny >> >> >> >> 2011/9/2 Henrik Mäkitaavola <henrik.makitaav...@gmail.com> >> >>> Hi again Johny, >>> >>> Do you have any problems with reassembling of fragmented packages? >>> When I try to ping a mote with a packet size bigger than 75 the mote >>> stops responding. I assume this is due to fragmentation. >>> Will investigate this more tomorrow. >>> >>> /Henrik >>> >>> >> >> -- >> Johny Mattsson >> Senior Software Engineer >> >> DiUS Computing Pty. Ltd. >> *where ideas are engineered >> * >> > >
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