[aprssig] IGate Registering for ANSRVR (Messaging failures)

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Fri Jul 15 11:12:01 EDT 2016


I'm going on memory which is known at times to be faulty, but I believe 
there is at least one IGate implementation that can be configured to 
consider "local" to be based on distance.  But I also believe it to be 
true that some IGates require hearing a position packet, not just any 
packet, in order to consider a station available for gating messages 
from APRS-IS to RF for that station.  I could be worng (sic) on both counts.

I can only state with conviction that APRSISCE/32 considers a station 
"recently" "local" based on 30 minutes and at most 2 hops used (although 
the calculation of that is interesting with stations originating WIDE2-1 
in a path, is that one used or was it originally that way?).  Eventually 
these will be configurable, but for now, they're hard-coded.  You can 
see the settings in an APRSISCE/32 instance by double-clicking the 
narrow vertical bar immediately to the right of the map.  it will show 
the following information:

> Close Stations
> <snip>
> 30 via RF (9 Direct 18 Local)
> IStoRF: 2 hops in 30 minutes

If you want to see just the stations considered "Local", use View / None 
followed by View / RF / Local.  Or you can send a ?APRSL query to an 
APRSISCE/32 IGate and it will respond with a list of all currently 
"Local" stations as defined for gating messages from the APRS-IS to RF.  
Note that this query is best done via the APRS-IS as the list can be 
fairly long.  A ?IGATE query will return the count of local, direct, and 
RF stations.  This information is also periodically transmitted in an 
IGate status packet.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

PS.  If anyone can speak authoritatively on what criteria the other 
IGate software uses for gating messages from the APRS-IS to RF, I'd be 
all ears... er eyes and would love to be corrected or confirmed in my 
recollection that one of them can consider distance rather than used hops.

On 7/15/2016 10:50 AM, Robert Bruninga via aprssig wrote:
>> In any case, most IGates must have received a position packet
>> from a station "recently" and consider it "close" enough
>> before messages will be gated from the APRS-IS for it.
> WHAT!!???  This totally breaks APRS as a messaging system.  Where did this
> come about.  It also breaks vicinity tracking, another very powerful APRS
> capability.
>
> There are MANY times and certainly in times of stress and emergency and
> backup comms when a position is not possible or easy.  How did this creep
> into the APRS system?
>
> How do we fix it?
>
> The criteria for IGateing back to RF is "LOCAL" meaning only that the
> station was heard DIRECT or on the first hop.  (though this can be a
> variable in remote areas)..
>
> Bob
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