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Weekly Report - 29/08/14

31

Aug

2014

Successful week this week:

I recompiled everything from 6lbr's development branch (i.e. native 6lbr, mbxxx slip-radio and mbxxx 6lbr-demo), explicitly setting PAN IDs to 0xabcd for the mbxxx builds (for consistency with other platforms). I also made sure to reset the MAC and RDC layers of each build to use the "null" drivers, which ensure that packets should be transmitted/received as quickly as the hardware allows (with no regard for power usage). This resulted in excellent quality packet transmission, with the possibility of 0% packet loss over several minutes of pinging the devices, even for fragmented packets. The RTT is a quite respectable 60-70ms for pings split into two fragments.

Using the development branch for the mbxxx platform meant that the memory footprint increased again, which was a big problem for the 6lbr-demo app. To offset this, I completely disabled TCP (since it isn't needed by CoAP), and halved most of the buffers used by RPL. Thanks to gcc's magical -fpack-struct=1 there is now a working CoAP server on the device that can return its uptime in seconds!