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[aprssig] Understanding IGATE

AE5PL Lists HamLists at ametx.com
Thu Jun 16 02:26:54 UTC 2005


IGate software (comes in a variety of clients and servers) gates to RF
messages addressed to stations "recently" heard on RF within a specified
"distance".  "Recently" is normally 30 minutes to an hour but some
software allows this to be configured by the sysop.  "Distance" may be
within X digipeater hops or within X miles (although this latter is
discouraged due to the reliance on the message addressee station having
transmitted a posit and the IGate having successfully decoded that
posit).  X may be configured via the sysop or may be fixed in some
software.

No, the IGates do not use variable paths.  It would take me very little
effort to show a multitude of circumstances where automated path
variation algorithms would quickly become self defeating.  I'll just
leave it at "consider variable propagation and variable digipeater
delays".

If you were not getting messages through to stations on RF, there could
be two reasons: the stations on RF were not within the coverage area of
an IGate (as defined above) or you were using an unverified connection
into APRS-IS.  APRS-IS servers and IGates will not pass messages
originated from Internet-connected software if that software did not
connect with a verified login.  Different software authors use different
methods for generating a verified login, but normally the software must
be registered with the author(s) using your callsign.  Verified logins
were put in place so IGates could identify packets that might not be
originated by amateurs thereby giving the IGates a method to prevent
those packets from being gated to RF.

Hope this clears things up.

73,

Pete Loveall AE5PL
mailto:pete at ae5pl.net 
________________________________

	From: Jeremy Bair
	Posted At: Wednesday, June 15, 2005 8:54 PM
	Subject: [aprssig] Understanding IGATE
	
	        I was not able to send a message to anyone on RF, but I
was able to receive without a problem. They were able to reach an IGATE
as their location was on findu, but as far as I can tell, they did not
reach an IGATE directly and went through several digipeaters. We
attempted to set up a local IGATE, but there must have been a
misconfiguration in the IGATE setup because it did not work.
	 
	        Are IGATEs able to gate messages to RF to stations heard
over a digipeater? If so, Is there any intelligence to IGATEs so that
the messages are transmitted following the minimum path possible and
choosing the best possible IGATE to limit the number of transmissions?




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