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<body class='hmmessage'><div dir='ltr'>Greetings.<br><br>I've noticed an unusual new experimental tocall value APZMVA, that seems to be associated with some oddly formatted APRS-IS messages. I was just curious what that might be.<br><br>Regarding the unusual formatting (which probably has nothing to do with the APZMVA program, as I am seeing from other tocalls as well), I am seeing packets from the APRS-IS that look like this:<br><br>K4FHK-15>APZMVA:K4FHK-15>APZMVA,TCPIP*,qAS,K4FHK-IS:;TNMVA64a2_072105zI</yn8U#*n __I-65-N DEBRIS, LEFT LNS BLOCKED<br><br>Note that the sender>tocall section is repeated twice, with a colon (':') delimiting the two occurrences. I'm wondering if this might be an issue with some dialects of the APRS-IS server code (specifically aprsc, since it is the one that shows up for every I-gate I've back-tracked), should my application not be reading the TCP socket connection fast enough, that the server might get the first part of a message stuffed in the stream, and then discards the rest of the message because of a TCP window overflow. That would make this appear like two concatenated messages with most of the first message gone, including the CRLF delimiter between the two messages. I've got a 48Kb TCP window size configured in my application, so there should be plenty of kernel-level buffering to allow for any pauses at the application level.<br><br>The occurrence doesn't seem to be a function of the incoming message rate.<br><br>Anybody have any ideas what's going on? Or is this a new format of I-gated messages from some I-gates? Note that some of the offending I-gates are UIView, so it can't be anything new (because other UIView I-gates aren't doing this).<br><br>Any suggestions would be welcome.<br><br>Andrew Pavlin, KA2DDO<br>author of YAAC ("Yet Another APRS Client")<br> </div></body>
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