[aprssig] Aggressive settings destroy the network

Robert Bruninga bruninga at usna.edu
Wed May 23 15:39:15 EDT 2007


> if it hears its own packet digipeated, it'll skip 
> the next n transmissions.  This means you can set a 
> fairly high beacon rate to get a better success 
> rate out in the middle of nowhere, but when you 
> get into an area with better coverage it automatically 
> cuts back on beacons.

Great on paper, and I had it in early APRSdos, but such an
algorithm again, does not protect the network (the #1 priority)
from problems.  In fact, it assures melt down over a certain
threshold.  I took it out.

The problem is, it is unstable positive feedback no matter how
you look at it.  The more collisions there are, the fewer
packets that get through.  Then this algorithm sends more (QRM),
and the result is LESS (gets through), and this goes on until
the network is gridlocked and nothing gets through.

No, early on, the design of APRS was to protect and share the
network as the top level design objective.  Then "allow" certain
settings.  And even allow aggressive settings if the operator
chose, but then ONLY for that session only.  Any such aggressive
settings were canceled on the next run.

I hope we can all agree that we should not design any settings
that add more to the network when less is getting through...
Protecting and sharing the network must be our number one
driving design factor.

Please read the "Tradegy of the Commons" as to what happens when
individual settings that benefit individuals at the expense of
the group will always spiral down to failure for eveyrone else.
See:

http://www.ew.usna.edu/~bruninga/aprs/fix14439.html

Thanks
Bob, WB4APR





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