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3. What kind of latency can I expect ?

For wider coverage, and to avoid tracking, geostationary satellites are "parked" in a fixed position relative to Earth, at 22,300 miles above the equator.

Radio waves travel at the speed of light, or about 186,000 miles per second. So any traffic from you to the satellite has to go 22,300 miles up, through the satellite, and be retransmitted 22,300 miles back down to its destination.

The net effect is that this one-way communication adds about a minimum of 240ms to the round trip time. This is from an ideal position as close to the satellite as possible (probably in the ocean at the equator). And remember, that if you send for a web page both the request and the response have to travel these distances in addition to any ground distance, for a minimum roundtrip of 89,200 miles (480ms). Add to that the terrestrial internet latency, gateways, proxies etc...

A more realistic expectation is a response of about 500-1000ms for two-way satellite, and 400-500ms for one-way.

Software and protocols can reduce the effect of latency for certain applications, but they can't change the physics, the latency remains.


  User Reviews/Comments:
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by Jason - 2012-05-08 14:08
Can software and/or protocols be used to reduce latency for World of Warcraft through satellite internet?
by Philip - 2012-06-02 09:47
The underlying protocols/software already try to compensate and reduce the visible effects of latency, however, they can't eliminate it - those are the physical limitations of the large distance.
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