[Tinyos-devel] default beacon period for FTSP

Branislav Kusy kusy at stanford.edu
Sun Feb 1 11:25:27 PST 2009


> On Sat, Jan 31, 2009 at 8:34 PM, Philip Levis <pal at cs.stanford.edu> wrote:
>> On Jan 31, 2009, at 8:21 PM, Omprakash Gnawali wrote:
>>
>>> I suggest a default beacon period of 30s for FTSP. 10s seem excessive.
>>>
>> Should FTSP use a trickle timer? The consistency condition would be the
>> linear regression coefficients. Or, better yet, temperature...
> 
> Interpolation might have interesting error properties if the minimum
> interval for Trickle is too short. Consistency condition should also
> include neighboring nodes getting out of sync or there has to be some
> kind of PULL bit.
> 
> Even if the FTSP owners want to stick with periodic beaconing, 10s is
> too frequent.
one problem with ftsp is the long time it takes to initialize (basically 
beacon period*3*#hops). i guess the 10s period was chosen for the demo 
application to converge quickly. in practice, we never used periods 
bellow 30s. i've had success with a 1 hour beacon period (achieving 50us 
average and 1.3ms maximum error in a 12 hop network). it required to 
increase the period progressively (start with 10sec, then 8min, and then 
1 hour period).

thus the trickle timer might be a good idea. it would be interesting to 
see some experiments.

brano


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