[aprssig] Does anybody know what APZMVA is?

[Lynn W. Deffenbaugh (Mr)]

K4FHK-10>APRX27,TCPIP*,qAC,FIFTH:>Originator of TNMVA objects. Send 
comments to tnmva at knobbe.us



Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

On 11/7/2015 4:17 PM, Andrew P. via aprssig wrote:
> Greetings.
>
> 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.
>
> 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:
>
> K4FHK-15>APZMVA:K4FHK-15>APZMVA,TCPIP*,qAS,K4FHK-IS:;TNMVA64a2_072105zI</yn8U#*n 
> __I-65-N DEBRIS, LEFT LNS BLOCKED
>
> 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.
>
> The occurrence doesn't seem to be a function of the incoming message rate.
>
> 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).
>
> Any suggestions would be welcome.
>
> Andrew Pavlin, KA2DDO
> author of YAAC ("Yet Another APRS Client")
>
>
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