<div dir="ltr"><div class="gmail_default"><font face="georgia, serif">Referencing several previous threads:</font></div><div class="gmail_default"><font face="georgia, serif"><a href="http://www.tapr.org/pipermail/aprssig/2016-July/045866.html">[aprssig] IGate Registering for ANSRVR (Messaging failures)</a><br></font></div><div class="gmail_default"><font face="georgia, serif"><br></font></div><div class="gmail_default"><font face="georgia, serif"><a href="http://www.tapr.org/pipermail/aprssig/2016-November/046314.html">[aprssig] IGATE message routing bug?</a><br></font></div><div class="gmail_default"><font face="georgia, serif"><br></font></div><div class="gmail_default"><font face="georgia, serif"><a href="http://www.tapr.org/pipermail/aprssig/2016-November/046360.html">[aprssig] local messaging</a><br></font></div><div class="gmail_default"><font face="georgia, serif"><br></font></div><div class="gmail_default"><font face="georgia, serif">We have clearly determined that we absolutely need to have an IGate author's design specification document, if we expect to realize any kind of consistency using the APRS for messaging while traveling outside of our local area. </font></div><div class="gmail_default"><font face="georgia, serif"><br></font></div><div class="gmail_default"><font face="georgia, serif">(Regardless, it would be wise to have situational awareness rather than assumptions, and test your assumptions. Good operating practice, as things stand, is to get a reasonable position packet out, and test message against a known sender (i.e. ANSRVR), and observe the response).</font></div><div class="gmail_default"><font face="georgia, serif"><br></font></div><div class="gmail_default"><font face="georgia, serif">To start, I would like to play with some ideas.</font></div><div class="gmail_default"><font face="georgia, serif">First, we have to look at the only thing anyone (author or user) has had to work with in many cases:</font></div><div class="gmail_default"><pre style="white-space:pre-wrap;color:rgb(0,0,0)"><a href="http://www.aprs-is.net/IGateDetails.aspx" style="font-family:georgia,serif">http://www.aprs-is.net/IGateDetails.aspx</a><font face="georgia, serif">
specifically, <Gating Criteria>
</font><font face="monospace, monospace">The following is the basic criteria for what an IGate gates to/from RF.
Gate message packets and associated posits to RF if all of the following
are true:
1. the receiving station has been heard within range within a predefined time period (range defined as digi hops, *distance*, or both).</font><font face="georgia, serif">
</Gating Criteria></font></pre></div><div class="gmail_default" style="font-family:georgia,serif">We could provide more detail in the new document, include some examples & reasoning, and make some suggestions for defaults, while recognizing the various local conditions.</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">So, taking a shot at #1, I am going to introduce the first idea, while tightening it up:</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">1.</div><div class="gmail_default" style="font-family:georgia,serif">The specific message destination station (CALL+SSID throughout this exercise) has been heard as the source of any packet type on RF, in the local area*, in a configurable time period, with a default of one hour (long enough for a station to beacon every 30 minutes, while allowing for at least one missed transmission). Messages may be transmitted to a specific list of callsigns of local operators, regardless of being heard locally, by the discretion of the operator, and depending on the capabilities of the software used.</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">*The local area has been coordinated with each of the local IGate operators and defined to consider:</div><div class="gmail_default" style="font-family:georgia,serif"><ol><li>transmitter power, HAAT, and antenna gain (PHG circle) <br></li><li>the ALOHA circles (packet channel saturation on RF) <br></li><li>local terrain<br></li><li>digipeater coverage<br></li></ol><div>For the purposes of APRS messaging support, if an IGate hears a station direct, or one hop, it is recommend that messages and courtesy 'sending station position reports' may be transmitted without regard to distance. In other words, do not wait for a position report from the destination station.</div><div><br></div><div>If an IGate hears a station as being two hops away, the distance may be used to restrict the status of heard to 'not local' only IF a position packet has been received. Until then, only messages (including ACKs) should be exchanged. This distance must be configurable by the local IGate operator. Once the distance on a two-hop destination has been determined, the courtesy 'sending station position reports' may be transmitted, the quantity sent being configurable to 0,1, or 2 by the IGate operator. (This is not intended to be a track).</div><div><br></div><div>In some locales, two hops may inject single packets from hundreds of miles away, with very little hope of reliably transmitting a message back to them.</div></div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">It is generally regarded that three or more hops away is not local, but regional. These stations heard should, by default, be considered NOT local, until a valid position packet has been received, AND it is within the locally defined distance. However, the recommendation (default) is to not to transmit, without a specific configuration option, that contains sufficient description of the consequences.</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">Have fun with that, and a good day!</div><div class="gmail_default" style="font-family:georgia,serif"><br></div><div class="gmail_default" style="font-family:georgia,serif">73,</div><div class="gmail_default" style="font-family:georgia,serif">Jim A.</div></div>