R&S M3SR 4100 Series, Operating Manual

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Operating Manual 6175.4760.02 – 01 4.9
M3SR Series 4100 Basics of ALE-2G LP
The following procedures are available:
• Protected Fine Time Request
With the protected fine time request, a net station inquires the time from the time server
or from another net station. The time lag between the two stations must not be greater
than two seconds. The received time quality then is poorer by at least one level than the
actual reference time. Time transmission is protected.
• Protected Coarse Time Request
With the protected coarse time request, the time lag between the two stations is allowed
to be as great as one minute. Here time transmission also is protected.
• Unprotected Time Request
With the unprotected time request, time transmission takes place without protection. The
inquiring station transmits a random value. The time is then transmitted with this random
value encrypted using the lattice algorithm.
4.3.2.3 Changing the Time Server
In most cases, a failure of the time server is tolerable for several days even with protection
level AL-2.This level does not require resynchronization before the 23
rd
day.
If, however, the time server fails to operate for a longer time, a different net station (and only
one) has to be designated time server. The new time server then instantaneously broadcasts
its time with the selected AL for the time server, its time quality now being 1 (= 20 ms).