[aprssig] RADIO paths in APRS Servers

[Curt, WE7U]

On Fri, 7 Aug 2009, Lynn W. Deffenbaugh (Mr) wrote:

> PPS.  However, if you actually have a chance to see the raw AX.25 packet, 
> there's an amazing lack of consistency on whether or not stations prior to 
> the final used one are marked used or not.  Consider the following paths 
> intercepted from my TT4's KISS stream directly off the RF.  Note how AI4LE-1 
> and KA1VRF-7 mark their source call "used" and the fact that all inserted 
> calls are actually marked used although if you look at the raw packets coming 
> over APRS-IS, only the last used station is so marked.

In the actual AX.25 packet each used digi slot _is_ marked.  What
you're seeing are textual representations of the AX.25 header
portions done by TNC or packet software that can represent that
header in a variety of ways.  Sometimes they mark each used one up
to the final used one, sometimes they only mark the last one used.


> Unfortunately, none of these packets show the non-used before used that I was 
> trying to show, but now that I think about it, those may result from a Digi 
> responding to a preemption (out of order) path as described on 
> http://wiki.argentdata.com/index.php?title=Digipeater_Setup#Preemption?

Unlikely.  Few people are using that feature.

-- 
Curt, WE7U.                         <http://www.eskimo.com/~archer>
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