[Tinyos-devel] Testing FTSP

[Andreas Köpke]

Am Montag, den 28.07.2008, 23:36 -0700 schrieb Branislav Kusy:
> 
> Omprakash Gnawali wrote:
> > On Mon, Jul 28, 2008 at 11:23 PM, Branislav Kusy <kusy at stanford.edu> wrote:
> >>
> >> Omprakash Gnawali wrote:
> >>> I wanted to see if the current version of FTSP in rc3 works well in a
> >>> multihop environment. I modified TestFtsp to send the return value of
> >>> call GlobalTime.local2Global(&rxTimestamp) through UART every 4s and
> >>> plotted the output - time on x-axis and node id on y-axis and (x,y) is
> >>> plotted if the return value is 1 suggesting FTSP is out of sync. If
> >>> FTSP is working well, we expect very few points on this graph. The
> >>> experiment was done on channel 25 on a 56-node TelosB testbed.
> >>>
> >>> Here are the results:
> >>> Default tx power: http://enl.usc.edu/~om_p/net2/test-ftsp/ftsp_result1.gif
> >>> tx power = 14: http://enl.usc.edu/~om_p/net2/test-ftsp/ftsp_result2.gif
> >>>
> >>> Is FTSP out of sync too often or not too far off the expected result?
> >> could i see the full log? (even better, if you could log the whole
> >> test_ftsp_msg_t struct over uart)
> > 
> > The logs from current experiment do not contain information other than
> > what is displayed on the graph.
> > 
> >> one reason can be (depending on how many hops you have) too high resync
> >> frequency, currently set to 3 seconds (TIMESYNC_RATE in TestFtsp/Makefile).
> >> we used ~30 sec for large scale tests.
> > 
> > I forgot to mention that I commented that line from Makefile so it is
> > using the default of 10s.
> these results are really bad, there should be no red crosses after the 
> initial synchronization period (first 40-50 seconds). is there a way to 
> re-run the experiment (first 500s would be enough) while logging the 
> whole debug struct(test_ftsp_msg_t)? could i also see the deployment map?
> 
> thanks,
> 
> brano

I suspect a bootstrap problem here. What happens if you start the clock
master node 2min before every other node? This way, it will declare
itself firmly as master an start to send beacons, at least the second
hop should follow suit.