[aprssig] Tracker Smart Pathing
Robert Bruninga
bruninga at usna.edu
Tue Mar 21 09:15:32 EST 2006
New name: Proportional Pathing:
Allan Pratt suggested that "Smart pathing" was not
really smart, since it is a fixed algorithm. We came
up with Proportinal Pathing instead. I have updated
this post:
>>> bruninga at usna.edu 03/20/06 7:59 AM >>>
The real thing we need in trackers is PROPORTIONAL
PATHING. That is, if the user selected (in the USA)
PROPORTIONAL PATHING = 2, Here is what he would
get every minute:
- Except as below, every packet goes DIRECT path (no digi)
- Every 2nd minute it would use the WIDE1-1 path
- Every 4th minute it would use WIDE1-1,WIDE2-1
If he set smart pathing =3 he would get the above plus
- Every 8th minute it would use WIDE1-1,WIDE2-2
If he set SMART PATHING= 4 he would get the
same plus a 4 hop path once every 16 minutes
The result is that for close in work or meeting someone
or local events or whatever, he gets good smooth
one-minute tracking and minimum QRM to anyone else.
For the local area (each digi he can hit), he gets a
comfortable 2 minute rate. For the large city and those
watching out 2 hops, he gets a 4 minute rate. And for
people watching from a long distance away, he gets an
8 minute rate.
This resolves the tradeoff between too high a rate (QRM)
and too low a rate (LATENCY, and LOW TRACK QUALITY)...
PROPORTIONAL PATHING would cut the QRM from each
mobile by a factor of 16 or more. (Each hop adds 4 more
copies in dense areas) And since mobiles are the largest
load on the network, this would make a HUGE difference.
While still providing good local tracking.
Also, since the WIDE1-1,WIDEn-N should work everywhere
in the USA, this one-size-fits-all appproach would make
setting up a tracker trivial, and help make the network
immune to user set-up errors.
de WB4APR, Bob
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