[aprssig] IGATE message routing bug?

Jason KG4WSV kg4wsv at gmail.com
Sun Nov 20 09:48:13 CST 2016


"If the only Igate in an area is RX only, that definitely breaks the
> system."
> I am picking on this statement, not the person who made it, because it has
> been echoed so many times.
> And it is wrong.


Sorry Jim, but it's dead on.  Rx-only is broken.  There may be a very few
reasons to operate RX-only; I think Pete covered most of them.  In general,
if you think you need RX-only on a long term general purpose gate, you're
probably doing it wrong.  e.g., IMO if you're worried about legality of
transmissions, don't turn off TX - turn off the station.


Someone (or multiple someones?) said, more or less, "the Igate spec is
vague, but that's OK."  No, it isn't. If it's vague it's not a spec,
definitely not a good one.

APRS is both a family of applications and a network. Flexibility in the
applications is a good thing - so we can have D700 style radios and 8 bit
trackers and mapping computer stations all working together, and new
features developed.

Vagueness (flexibility?) in the network infrastructure is BAD. Users and
applications cannot know what to expect, so communications are unreliable.
If your network is unreliable, it's broken.  If it's unreliable because
there are very different implementations due to a vague spec, the spec is
broken.

In particular:

the receiving station has been heard within range within a predefined time
> period (range defined as digi hops, distance, or both)


I take exception to the "or both".  If I can hear it on RF it certainly is,
by some definition, _local_, totally independent of the existence or even
capability of generating a position report.

If I hear it directly (no hops) on RF, it is local. It absolutely does not
matter if it never in the history of the universe transmits a position
report. it. is. local.

IMO, if I hear it within the number of hops that I'm willing to transmit,
it is also local. (and yes I'm aware of the extremely problematic nature of
determining the hop count on an incoming packet. that's another case of a
vague network infrastructure specification biting us.)

and bringing tropospheric ducting into the discussion is nonsense, unless
it just happens a _lot_ more in other parts of the world than it does here
in the southeast US.  If so, feel free to educate me.

-Jason
kg4wsv
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