[aprssig] I-gate loops for telemetry support text messages

[Pete Loveall AE5PL Lists]

Yes.  Both 1 & 2.  IGates should not gate to RF message packets that are "self-addressed" (should only be Telemetry Messages but might be others).  IGate gate range should be based on hops and should not gate beyond "local" (however you define that and I know that it is difficult with the various implementations of the WIDEn-n paradigm).

Hope this helps.

73,

Pete Loveall AE5PL
pete at ae5pl dot net



-----Original Message-----
From: aprssig <aprssig-bounces at lists.tapr.org> On Behalf Of Andrew Pavlin via aprssig
Sent: Wednesday, September 22, 2021 4:45 PM
To: TAPR APRS Mailing List <aprssig at lists.tapr.org>
Subject: [aprssig] I-gate loops for telemetry support text messages

Greetings.

I just discovered an interesting "loop" caused by I-gating. My Tx I-gate received a text message from APRS-IS that was originally sent by a digipeater that I received both by Internet and by long-range digpeater hop on RF. So, I've heard the station on RF (but not _local_ RF, because there were one to three digipeaters in the path by the time I received it on RF). It is one of the self-addressed text messages that go with telemetry messages to say how to interpret the telemetry (EQNS, BITS, UNIT, PARM).

So, my Tx I-gate, having received from the Internet a text message addressed to a station it has heard over RF, proceeded to transmit the text message to RF (but without enough digipeat aliases to actually reach the station).

This sounds like a bug in my I-gate. So is the correct solution:

1. never Tx I-gate self-addressed text messages.

2. never Tx I-gate to RF stations that require more hops than I allow on my Tx I-gate digipeat path (i.e., for Tx I-gates that can put a WIDE1-1 or WIDE2-1 on their retransmissions). For the common case of no digipeat path for Tx I-gating, the RF station would have to be heard directly (not by digipeater) by the I-gate.

So how should I fix my I-gate?

Andrew, KA2DDO
author of YAAC ("Yet Another APRS Client")