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[aprssig] Periodic Disconnects from APRS-IS

AE5PL Lists HamLists at ametx.com
Thu Jan 18 19:28:52 UTC 2007


This has nothing to do with programming language or how TCP works.  This
has to do with what APRS is: a near real-time reporting system, and what
APRS-IS is: a very basic APRS packet transport system built originally
on TCP.  Yes, it is very inefficient because the Nagel algorithm is
turned off (nothing to do with what language clients or servers are
programmed in).  The Nagel algorithm has to be turned off if significant
delays are not to be incurred due to buffering of packets (which is what
we saw a few years ago before we started turning off the Nagel
algorithm).  Hope this clears up why the protocol is inefficient and why
it will stay that way when using TCP.

Also, my posts had nothing to do with bandwidth at the server.  The
bandwidth issue I spoke of is at the client and is primarily a
processing issue in the client software although it can also be
problematic for limited bandwidth residential configurations.

73,

Pete Loveall AE5PL
pete at ae5pl.net

> -----Original Message-----
> From: Scott Miller
> Posted At: Thursday, January 18, 2007 11:16 AM
> Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
> 
> Last time I looked at a TCP dump of an APRS-IS connection, it seemed
to
> be
> making rather inefficient use of the bandwidth.  I saw exactly one
line
> per
> packet.  For slow ports (message only, local filters) this is fine -
it




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