[aprssig] Universal Messaging (and new qAP feedback?)

Pete Loveall AE5PL Lists hamlists at ametx.com
Wed Oct 29 12:11:52 EDT 2008

> -----Original Message-----
> From: Robert Bruninga
> Sent: Wednesday, October 29, 2008 10:57 AM
> Subject: [aprssig] Universal Messaging (and new qAP feedback?)
> Maybe it could be a new "qAP" packet.  Following the "qAP" would
> be the callsign of the Igate, then its RF PATH (maybe WIDE2-2,
> or WIDE1-1, or whatever it is using).  This kind of feedback on
> the APRS-IS would be very valuable.  Pete, AE5PL and Steve, K4HG
> and others should have the best ideas how to do this kind of
> stuff.  Of course, all of the existing Uiview Igates will never
> be upgradeable, but we have to start somewhere and now is a good
> time.
> Anyway, back to the UNIVERSAL MESSAGING ISSUE, by having this
> "qAP" feedback information, then we can see how outgoing
> messages are being handled by the APRS-IS and from that improve
> our overall goal of Universal Messaging Connectivity.

Please do NOT make ad-hoc changes to the q algorithm.  It is in place for a specific purpose and does not exist for random "I think I'll abuse it this way" implementations.  The q algorithm exists SOLELY on APRS-IS (not on RF) and is used for loop control by the APRS-IS servers.  As a benefit, it shows "port-of-entry" but that is an added benefit, not its primary use.  All q algorithm enabled servers depend on the integrity of this construct.  Deviations such as you proposed here will break APRS-IS.

Sorry to be so terse but this "let's throw this against the wall and see if it sticks" type of posting can cause significant damage as people who are not knowledgeable of how APRS-IS and its components work blindly follow these lines of thought break what the network.

Your proposal is a solution looking for a problem.  Looking at raw packets (available on most of the APRS database servers) will readily tell you many things:

Was the message generated?
Was the message numbered or unnumbered?
If numbered, was an ack seen from the receiving station?

Because of dupe checking, all RF activity (digipeat paths, etc.) need to be viewed on RF.  APRS-IS has never been a useful tool for RF diagnostics because its entire premise depends on duplicate payload packets being dropped.


Pete Loveall AE5PL
pete at ae5pl dot net

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