[aprssig] packet delays through internet
Russ Chadwick
russ at wxqa.com
Sun Mar 20 16:07:05 EDT 2011
Regarding the EOSS balloon packet delays through the internet that were
reported last weekend:
Significant packet delays were noted through an I-gate that consisted of
a D710, UI-View and Comcast ISP. We (Mark, KC0D; Nick, N0LP; and I) did
tests yesterday and found the problem to be that UI-View was using
Xon/Xoff flow control while the D710 was not using flow control. Delays
of a few minutes to 90 minutes were noted with this set-up.
After we changed UI-View to having no flow control, expected delays of
just a few seconds were noted almost all of the time. In addition to
the delays becoming normal, the problem with bad characters in the
I-gated packets also went away.
At 2000 on March 19 we started a test where a timestamped packet on
144.340 MHz was sent to the I-gate every minute. This test continued
overnight to 1800 on March 20. The results for each packet can be
viewed here,
http://www.findu.com/cgi-bin/raw.cgi?call=KB0TVJ-4&time=1
Russ KB0TVJ
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