Geostationary satellites are placed at about 36'000 km from the earth
and turn with earth rotation speed. So they appear stationary and are
in general perpendicular to the equator.
The radio signal propagation time over the distance
between the satellite and the earth's surface is between 239.6 ms
and 279.0 ms, so that the roundtrip delay is not more than 558 ms.
This delay influences communication protocol behaviour, so special
tests are required. The Line Server Unit
(LSU) allows the simulation of this satellite delay for a large
variety of situations.
The Satellite Delay function operates both on TDM (E1/T1) signals
and on asynchronous channels such as ATM or Ethernet. This feature
can be activated together with other simulation or monitoring activities
on communication channels of any bandwidth, from a single TDM time
slot to a full Gigabit Ethernet connection.
