[net2-wg] problem with the timer that controls routing beacon rate in CtpRoutingEngineP.nc

[Philip Levis]

On Tue, 2008-03-18 at 14:29 -0800, Omprakash Gnawali wrote:
> >  > 2. Triggered route updates using the same timer as Trickle timer. We
> >  > thought we would be able to fix this by calling resetInterval()
> >  > instead of starting the timer when we need to generate on-demand
> >  > beacons. This will ensure that there is only one way to change the
> >  > Timer. Unfortunately, this will not work - we want to control how long
> >  > to wait until we send a beacon in case of on-demand beacons depending
> >  > on the situation (trigger update vs trigger immediate update), not
> >  > possible using a single resetInterval() call.
> >
> >  Why are there two different cases? What is the difference? IIRC, we were
> >  originally trying to distinguish beacons that should send soon and
> >  beacons that should send NOW. But in the case of trickle, we can just
> >  reduce this to beacons that should send NOW and take advantage of the
> >  exponential decay. So we send a few extra packets. Let's simplify it.
> 
> Are you saying that reset should always trigger an immediate beacon?
> Right now we set the timer to fire at min interval upon reset.

You should never send an *immediate beacon.* IIRC, even the "immediate"
beacon is a 32ms timer. So the trickle interval tau_l should be very
small...

Phil