Ssu-Based Reference Selection Scenarios - Symmetricom TimeProvider 1000 User Manual

Chapter 1 Overview of the TimeProvider
Reference Input Signals
If the incoming signal does not include SSMs, or if you disable them, then you can
provision the Quality Level to an appropriate value. The QLEVEL value is used in
the same manner as the incoming SSM to determine which input is used when the
active input is disqualified. SSMs are described in more detail in
Status Messages
SSU Mode
Table 1-2 illustrates which input is the active system reference under several
different input conditions when the TimeProvider is in the SSU mode.
Table 1-2. SSU-Based Reference Selection Scenarios
QLevel on
Sequence
PRS
1 2
2 4
3 4
4 4
5 4
6 4
7 2
8 2
9 2
10 LOS
11 LOS
12 LOS
13 2
14 2
Note:
1
Non-revertive example. Priority Levels set to: PRS = 3, INP1 = 3, and INP2 = 3
2
Revertive example. Priority Levels set to: PRS = 2, INP1 = 1, and INP2 = 2
34 TimeProvider User's Guide
(SSMs), on page 37.
QLevel on QLevel on
INP1 INP2
2 2
2 2
4 2
4 4
4 2
2 2
2 2
2 LOS
LOS 2
LOS 2
LOS LOS
LOS 2
LOS 2
2 2
Synchronization
Active Reference
1
Non-Revertive
PRS INP1
INP1 INP1
INP2 INP2
INP2 INP1
INP2 INP2
INP2 INP1
INP2 INP1
PRS INP1
PRS PRS
INP2 INP2
Holdover Holdover
INP2 INP2
INP2 PRS
INP2 INP1
097-58001-02 Revision C – August 2005
2
Revertive