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

Pete Loveall AE5PL Lists hamlists at ametx.com
Mon Dec 2 12:17:22 CST 2013

No, you read way too much into my statement so I will restate it below...

> -----Original Message-----
> From: Steve Dimse
> Sent: Monday, December 02, 2013 10:50 AM
> Of course. However by definition what is being removed are the duplicates
> of the message, not the message itself. One copy, the first copy, gets
> through. However from below I see you are using filtering and not dup
> checking as the agent here.

No, I am not using filtering (this has nothing to do with filters except that you made the mistake of including them in your thesis) as any type of agent.  See below.

> > The second place where you have a misunderstanding is with the
> statement "still send downstream messages to that callsign because the RF
> station's position falls within the IGate filter footprint".  There are multiple
> errors in this statement.  First, the server doesn't "send downstream
> messages to that callsign" because it passes packets, period.
> > On most limited feed ports, the server also maintains a "last heard" list for
> the connection so it can also pass message packets and associated posit
> packets that are addressed to stations gated to the server by the connected
> client.
> OK the light is slowly peeking into my aging skull.
> The last heard filter is not mentioned in the filter or Igate design and details
> pages. Where is it explained on aprs-is.org? If I missed it I'm sorry, but it is a

Yes, it is mentioned and it is not a filter.  Limited feed ports have always supported "last heard" tables on a per-client basis to support messaging for IGates using limited feed ports.  This was a principle incorporated over 10 years ago when server-side filters were created so that filtering would have nothing to do with whether a message packet is passed to the client.  Instead, a message packet is passed to the client using a limited feed if it is addressed to the client or if it is addressed to a station the client as recently gated to the server.

> Does the range filter override this filtering? Yes, I was assuming IGates would

No, as I stated repeatedly, filters including the range and area filters have -nothing- to do with whether a message packet is passed to a client on a limited feed port.

> You are attempting the defacto routing of messages. Since you cannot

No, I am not.  The server passes message packets to the client on a limited feed port (note there is no mention of "filters") based solely on the station that the message is addressed to and that is based solely on whether it is addressed to the client or to a station the client has recently gated packets to the server for.

> delays. Don't send them the packets you don't want them to think about
> transmitting.

Actually, you do send them packets directly injected into APRS-IS by recently heard stations so the IGate can determine if an RF station is also directly attached (also described in the www.aprs-is.net pages).  This reduces needless gating to RF of messages destined for a station directly attached to APRS-IS.

> So yes, I will concede that 1way gates screw this up. But I'm not happy with
> it. I always thought the decisions about what IGates would transmit belonged
> in the local IGate operator's hands. I don't think it is appropriate for the

They do and they continue to.  This entire setup is to provide them the ability to gate what they want to -and- to ensure proper messaging regardless of their filter settings.  An IGate operator has never had the ability to say "only gate messages for station xyz".

Again, I gave a complete example where the RX-only IGate will break messaging in addition to its inability to message (please reread my prior post completely instead of trying to break bits and pieces out of it).


Pete Loveall AE5PL
pete at ae5pl dot net

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