[aprssig] are write-only APRS-IS clients valid?

Dave Torrey kd8gbh at woodsidelane.net
Mon Dec 2 14:41:20 CST 2013


Ok, that clears it up for me quite a bit.

I'm running a receive-only iGate (let the beating begin).  It's aprx,
and I believe it has an integral server (it offers the usual TCP ports,
among other things).

I have been asked several times to turn on gating back to RF.  I'm not
opposed to it, but haven't gotten around to it yet either.  If I do, and
I understand you correctly:

1) If I add no filters, I should be receiving appropriate messages to
gate to RF, according to stations I have recently gated to IS.

2) If I add filters (say, geographic), that could cause loss of some
messages that should come back through me.

3) If the server or servers in the chain to which I subscribe have
filters (I would hope they don't, but for the sake of argument...), that
would have a similar effect to #2.


In regards #2, I might like to have some filtering enabled for other
reasons, but would hope the recently-heard list trumps (by including
such packets) any filters I set up.

In regards to your reply to KD7LXL, that is how I had imagined the
system working -- a server merely sends messages back out to clients,
based on where it heard a station, and the clients decide whether or not
to gate to RF.  I am now somewhat confused as to what the debate is
about, but that's nothing new.  It makes sense to me that RF
contention/access be managed at the point of transmission, and nowhere
else.

Thanks,
Dave
KD8GBH

On Mon, 2013-12-02 at 14:05 -0600, Pete Loveall AE5PL Lists wrote:
> > -----Original Message-----
> > From: Dave Torrey
> > Sent: Monday, December 02, 2013 1:31 PM
> > 
> > From the discussion so far, I gather that this is not the case, and that the
> > server maintains some sort of most-recently-heard list.  If it's using that list to
> > choose a single igate by which to route messages back to stations, then I'd
> > argue it isn't quite literally in keeping with the description quoted above.
> 
> The statement implies there is a "recently heard" list for every client because it wouldn't otherwise know if a station was heard via that client.  The statement is not a "how to implement" statement, it describes what a client receives via a limited feed port.  The server does not maintain a single list for the server, it maintains a list for each client independently.  As I stated, the RX-only breaks messaging if it is either the only station gating to APRS-IS a particular RF station or if the common implementation of an IGate with integral server is deployed in the same area.  And, yes, this configuration accounts for most of the hundreds of javAPRSrvr installations.  The statement is very accurate in what is delivered to the client attached to a server but you must remember, that server must be able to see all as well which is not the case in most IGate/integral server implementations.
> 
> 73,
> 
> Pete Loveall AE5PL
> pete at ae5pl dot net
> 
> 
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