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[aprssig] Periodic Disconnects from APRS-IS

Scott Miller scott at opentrac.org
Fri Jan 19 02:45:37 UTC 2007


That's why I suggested it'd be useful on high-volume ports.  If you're
carrying the full IS feed, you're looking at maybe 100 msec of buffering
time.  If it can be supported by the server software, why not reserve a
buffered port?

Scott
N1VG 

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of AE5PL Lists
> Sent: Thursday, January 18, 2007 11:29 AM
> To: TAPR APRS Mailing List
> Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
> 
> 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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