500 RTT, + 150 jitter buffer, + something else... it will be 700 - 800 msec, more likely. When we worked with a few sattelliite lines (5 years ago), I never saw ping rtt less than 800 msec. Of course, it does not mean that you can not see RTT = 500 msec (but I never saw it). But I was talking aboutt other thing - ~1second delay != bad quality, it is just a delay, which means that, if you have good echo cancellers (which is interesting question) and follow talking discipline, you can talk without any problems. It explains, why satellite links + VoIP can be a good combination (moreover; after satellite delay, which is 500 - 600 msec, VoIP additional delay ,which is 50 - 150 msec, does not change overall delay so much, as in case of VoIP over bad link _vs_ traditional telephony (200 msec vs 20 msec = 10 times; 800 msec vs. 600 msec = 30%).
## On 2004-03-27 19:30 -0800 Alexei Roudnev typed:
AR> AR> It means, that satellite (with it's 1 second delay and unavoidable
echo)
Geosynchronous satellite IP link RTT can be just over 500 mill-sec (real life experience) IMHO thats a rather significant difference
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Rafi