[aprssig] Recommended Behavior for Read-Only APRS-IS Clients?

Kenneth Finnegan kennethfinnegan2007 at gmail.com
Sat Apr 18 22:11:01 CDT 2015


As always, I come to you with an oddly specific question on undefined
APRS behavior.

When someone is implementing an APRS-IS client, they would typically
connect to server.aprs.net:14580, and send a login line containing
"user MYCALL pass **** [filter ...]"

The APRS-IS server would then respond with a "# Welcome etc. etc." and
start feeding the IS client any requested / implicit packets that
should be sent to the client, and TYPICALLY send a "# I am an APRS-IS
server and am alive" line every 20 seconds.

My question is: What is the recommended best practices when
implementing a read-only APRS-IS client for connection keep-alive in
the client->server direction? (A typical read-only application could
be something like a telemetry collection daemon)

I know that the default ClientTimeout for aprsc is 48 hours, so I'd
expect clients wouldn't need to send keep alive lines anywhere near
the APRS-IS keep-alive frequency. I have found examples of mute
clients connected to IS servers on the order of weeks, but that seems
to depend on unusually forgiving behavior by the server.

My guess would be I should send a "# APRS-IS client keep-alive" line
once every... hour? Is that acceptable behavior? Is there a strong
reason why it should be "MYCALL>APRS:>Comment" vs the same "# Comment"
format that the IS server uses?
Kenneth Finnegan, W6KWF

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