[Tinyos-help] Re: Is it possible to change a collection tree's root?

[Hugo Sousa]

Hi Phillip, thanks for the help,

I haven't tried using the debug interface, but I will.

Right after reading your mail I tried using another topology, more
mesh-like, and it worked. The net topology I was using was very
simple, just a plain tree topology, with one 4-node loop, and a "line"
of nodes (nodes that are just reachable by one path). With that
topology it didn't work. I tried other simple topologies, like
all-in-line, or others topologies where most nodes don't have more
than 2 or 3 neighbours. Changing the root node seems to fail in those
situations.

Regards,
Hugo


On 8/1/07, Philip Levis <pal at cs.stanford.edu> wrote:
> On Aug 1, 2007, at 4:38 AM, Hugo Sousa wrote:
>
> > I've even tried changing the CtpRoutingEngineP parameters in CtpP,
> > like Phillip said in another thread, but still doesn't work. Isn't CTP
> > prepared to handle tree root changes? What about topology changes?
>
> In theory, it should handle tree root changes and topology changes
> fine. We've certainly tested the latter in testbeds, and I've tested
> the former in simulation. All a node does is try to route through the
> neighbor that has the lowest cost route. The only possibility I can
> think of is that nodes which are close to the old root are forming
> large routing loops as they try to find a route. But this would
> increase their route cost, causing them to be unattractive as next hops.
>
> Do you have a wired backchannel? CTP has extensive logging
> information that it can send to the serial port, with which you can
> figure out exactly what's going on.
>
> Phil
>