[aprssig] Log Files and APRS-IS

AE5PL Lists HamLists at ametx.com
Sat Apr 30 08:11:49 EDT 2005

I would like to expand on my previous post considering some of the
inquiries I have received.  As I stated before, the post was purposely
not specific about which software I had identified as being problematic.
This is because I have no way to test _all_ software and software
versions.  Also, I know that the clients I have identified as having the
problem have also been fixed, but there are a lot of buggy versions
still in use.

More important is the understanding by APRS users regarding the
difference in log data versus RF and APRS-IS data.  APRS is real-time
(or near real-time) and so the RF and Internet network for APRS is
real-time.  When you play back a log file into your client, you are
playing back historical data, not real-time data.  If you do this
offline (from both RF and Internet), your playback will be unaffected by
the real-time network data.  However, if you do this online, you risk
corrupting your playback with interspersed real-time data AND you risk
corrupting the real-time network data by possible insertion of
historical data to the network.

***So, if you want to view historical log data, do it offline to protect
your playback and protect the real-time network.***

The historical ports on javAPRSSrvr are unidirectional (server->client)
for just this reason; to prevent IGates, clients, and servers from
reintroducing historical data into the network.


Pete Loveall AE5PL
mailto:pete at ae5pl.net 

> -----Original Message-----
> From: AE5PL Lists
> Posted At: Friday, April 29, 2005 5:39 AM
> Subject: [aprssig] Log Files and APRS-IS
> So, to avoid creating misleading tracks, invalid weather reports, etc.
> PLEASE DO NOT replay logs while connected to APRS-IS (APRS on 
> the Internet).  If you must replay a log, PLEASE disconnect 
> your software from APRS-IS while you do the replay.
> Don't bother asking which software performs incorrectly.  I 
> have no intention of turning this into a slam-the-software 
> thread.  Assume that the software you are using performs this 
> way and take the appropriate steps (paragraph above) to 
> prevent log replays from polluting the APRS-IS data stream.

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