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[aprssig] More digis are changing to the new paradigm

Jason Winningham jdw at eng.uah.edu
Tue Jul 5 17:48:14 UTC 2005


On Jul 5, 2005, at 8:27 AM, Robert Bruninga wrote:

> This will guarantee several things:
>
> 1) the sender will have no idea how far his packets will go

Why?  How do we know how far they'll go _now_?  (answer: we don't!)

> 2) the network will always be 100% busy with routine
>      lights-are-on-noone-home packets doing nothing

Again, why?  If we design it to saturate the channel, sure it will be 
that way.  If we are just a little bit smart when we design it, there 
will be no more traffic than the channel can support.

> 3) The user that needs to get packets from A to B cannot

Why?  If we design a network that is smarter and more efficient, it can 
be easier and more reliable to get from A to B.  For that matter, we 
can easily design in backwards (and I do mean backwards) compatibility 
for those who insist on using source routing.

> 4) The priority user with a LIVE immediate need cannot
> communicate any better than a home station with non
> moving beacons.

Why?

>   And he wont have any clue if the system
> will deliver his packets too where they need to go right-now.

APRS uses AX.25 datagrams (UI frames). Datagrams are unverified, 
unacknowledged, best effort unguaranteed delivery _by_ _definition_.  
If you want guaranteed delivery, use connected mode AX.25, or TCP, or 
some protocol that supports it.

By intelligently managing the network we can increase the successful 
delivery rate of these datagrams.  We can also allow the user to more 
intelligently specify where he wants the packets to go (to an igate, X 
number of hops, Y number of miles, state/region/country, etc) for a 
better success rate and decreased network load.

> 5) The network becomes completely indeterminant.

The network is _already_ completely indeterminant.  If you want 
determinism, you need connected mode, etc.

> 6) The network is extremely dependent on sysop-hands
> on-tweaking to do anyting other than "routine".  And
> experience shows that getting a SYSOP to make real
> time changes in some areas takes not just hours, but
> months.

Thanks for making my point.  This is _exactly_ why the infrastructure 
needs to have smart well designed components that can react 
appropriately to conditions on a minute-to-minute basis, not a 
year-to-year basis.

-Jason
kg4wsv





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