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[aprssig] What stations should respond to APRS queries?

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Thu Mar 8 19:02:17 UTC 2012

On 3/8/2012 1:24 PM, Andrew P. wrote:
> Which of these queries are currently supported by other clients,

APRSISCE/32 answers many directed queries including:

?APRSD - Returns directly heard (no path used) stations
?APRSL - Returns recently local stations (as determined by hops and time)
?APRSH - Returns all stations recently heard via RF
?APRSM - Retransmits the oldest non-acked message directed to the querier
?APRSO - Triggers transmission of enabled objects
?APRSP - Triggers a posit to be transmitted
?APRSS - Returns a status of the client
?APRST/?PING? - Returns the path over which the query was heard
?ABOUT/?APRSV/?VER - Returns the client version string
?DX - Returns information about long-distance direct (no hops) RF receptions
?IGATE - Returns IGate status including MSG_CNT= LOC_CNT= DIR_CNT= RF_CNT=
?IGATE additional returns status of all enabled RF ports and their 
current DX reception

I don't recall right now what I do with non-directed queries other than 
NOT gating them to APRS-IS if received over RF.  I do not support 
generating non-directed queries at this time.

> and can the clients choose to selectively refuse to answer?

A client can do whatever the coder wants it to do.  I answer all 
received queries as I consider it good for remote network health diagnosis.

> Can the clients refuse to answer an IGated query?

A client can do whatever the coder wants it to do.  I answer all 
queries, regardless of where it came from.

> Can the clients otherwise blacklist remote stations (generically or station-specifically) from getting answers?

I personally consider blacklisting an ostrich response to probable 
network issues and therefore do not currently support any form of 
blacklisting in APRSISCE/32.

> I'm curious, because I don't seem to be able to get answers from any clients (other than other instances of my own) from an IGate-only connected client.

Send any of the queries above to my local IGate KJ4ERJ-1 and you should 
receive answers.  If not, please send a message to KJ4ERJ-12 and I'll 
see if it's even hearing the query.

> Any advice would be appreciated.

BTW, acks should  be issued immediately upon receiving any message that 
specifies a sequence.  The ack should not be delayed for operator action 
or attention as that will generate unnecessary retries from the sender 
clogging the network.  Confirmation that an operator has actually seen a 
message can be done when that operator sends a response, not by 
withholding the ack.

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

> Andrew Pavlin, KA2DDO
> author of YAAC (Yet Another APRS Client)
> http://www.findtheater.com/ka2ddo/YAAC.html
> Sent from my Verizon Wireless BlackBerry
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