Potential Disadvantages of Satellite Data Systems - Delays

From INVESaTWIKI

Delays

Satellite systems have inherent delays due to distance. The satellite is in geosynchronous orbit, approximately 22,000 miles from the Earth's surface. Therefore, any signal has to travel up and back, for a total round trip of 44,000 miles, which causes a noticeable delay, or latency. This delay is about 250 milliseconds, or a quarter of a second, one way (i.e., from the user ground station to the uplink facility) and adversely affects the performance of time-sensitive applications such as telephony. To send a request and receive a response, the user will experience a minimum of about one half second of latency.
While the delay is not noticeable when receiving a data download (such as a file transfer) or watching a video stream, any interactive service (such as videoconferencing or voice over IP) will be adversely affected. With the round-trip time taking at least one half of a second, the video or audio interactivity is severely degraded as compared to wireline circuits (such as a T-1), whose latency is on the order of 1ms per 100 physical circuit miles. [1],[2]

References

[1] more.net
"An Introduction to Satellite-based Data Services".

[2] Pioneer Consulting
"Abridged executive summary".