R&S M3SR 4100 Series, Operating Manual

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M3SR Series 4100 Selecting the Protection Level
4.60 Operating Manual 6175.4760.02 – 01
4.3.6.24 Selecting the Protection Level
Softkey Type Description
Listbox
In the central area the currently active value is
displayed.
1. Press softkey 'LINK PROT Level'.
2. Select desired value from listbox with the
knob.
3. Press 'ENT' to confirm.
Possible values:
• AL-0
• AL-1
• AL-2
Protection level 2 guarantees maximum secu-
rity (protection interval 2 s) at high demands
on network synchronization, whereas protec-
tion level 1 allows slightly less security (protec-
tion interval 60 s) at lower demands on
network synchronization. The protection inter-
val defines the time during which the input
quantities of the encryption algorithm are con-
stant.
The 24-bit ALE (= Automatic Link Establish-
ment) words for linking are encrypted by
means of the lattice algorithm. Input quantities
for this algorithm are the user-defined key (see
sect. 4.3.6.23 Entering the Key), the frequen-
cy, date and time of day.
The key can be 56 bits long, allowing as many
as 2
56
different keys.