[aprssig] APRX aprs-is filtering

Pete Loveall AE5PL Lists hamlists at ametx.com
Fri Aug 6 18:29:53 CDT 2010

No as this was never discussed as a requirement back when IGate support being reviewed.  One major reason: most IGates don't gate to RF all messages for a received callsign and this, I believe, is on purpose.  Yes, a client "should" display all messages seen for the client's callsign.  Most display these messages independently of messages specifically for the station and the station "must not" acknowledge any messages for stations other than itself.

In the RF world, this seems like a simple issue but becomes very complex and potentially hazardous when you introduce geographically diverse stations running under the same callsign.  Because most if not all IGate software at the time of the design of the IGate support in javAPRSSrvr did not gate to RF except for last heard stations and because the discussions at the time solely focused on providing proper APRS messaging support for stations recently heard on RF, the IGate support in javAPRSSrvr also focuses solely on APRS messaging support for stations recently heard on RF.

Once again, the "intent" of the spec and actual implementation by software authors are apparently divergent in this area.  Personally, I don't think it makes sense to risk potential RF network issues by implementing this, especially since most of the IGate software in use today (over 90%) would not gate those messages to RF anyway (and most of the IGate software is no longer modifiable either).


Pete Loveall AE5PL
pete at ae5pl dot net

> -----Original Message-----
> From: Robert Bruninga
> Sent: Friday, August 06, 2010 5:25 PM
> That is a good thing to check....  It is in keeping with the
> intent of the spec, that a person goes from base, to mobile to
> HT, to blackberry at any time, and so his messages were intended
> to be copied by all his stations.  Thus, the Igate (and filtered
> server) should return to RF any such message as long as there is
> ANY of his SSID stations in the local area.

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