On Apr 6, 2008, at 5:56 AM, Bulut ERSAVAS wrote:
Hi Omprakash,
I can't really say that it is quite deterministic. In networks where
we collect measurements every 15 minutes, we lost path to some nodes
within a few hours to half a day. Our networks are generally small
(i.e. 3 to 5 nodes per network). There are cases where we lost the
connection in a single-hop-to-root setting. As we are experimenting,
the nodes are not moved around without our knowledge.
This issue happens specifically at two locations. One is a
greenhouse with barely any obstacles. The other is a closed
environment where there are reflective metal walls. For the latter
case, the motes are placed very close to each other (about 10-15
meters).
Would rebooting the motes periodically (e.g. every few hours) help
ease this problem? Is it possible for CTP to get stuck in a state
where it can no longer discover a path to root?
As long as there is a path to the root, CTP should be able to find it.
That being said, there could be a bug in CTP or a bug in your
application. Given how heavily CTP is tested, I'm leery of assuming
it's a bug there.
Stationary nodes does not mean the topology doesn't change. You can
easily see significant signal strength shifts due to temperature and
humidity. One study on ATPC showed RSSI vary by as up to 10dB for
nodes sitting in on a lawn, over 24 hours.
Phil
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