Synchronization Status Messages; Standard Ssm Definitions - Symmetricom TSG-3800 Series User Manual

Operating the TSG-3800
Selecting the Input Reference Signal

Synchronization Status Messages

Synchronization Status Message (SSM) provisioning is a dual purpose setting.
When using the Automatic SSM Mode setting on the inputs, it may be used indicate
the SSM quality level for signals that are SSM-capable. This setting may also be
used in conjunction with the SSM Alarm Mode parameter to indicate that the
received SSM is below this provisioned SSM. When using the Provisioned SSM
Mode, the Input SSM is set to Stratum Unknown (STU) or default. The input ports
default to STU Provisioned SSM. You can provision the input to be ST1 (stratum 1
or PRS), STU, ST2 (stratum 2) or ST3 (stratum 3); this assigns a minimum level for
that input port, which can be used to inform the user that the received SSM is below
this level.
For inputs that are not receiving SSMs, the provisioned SSM may be transmitted by
the TSG-3800 if the input is selected as the reference. The action taken by this
event is user defined to IGNORE, REPORT, ALARM (set minor alarm) or FAIL
(invalid input). The provisioned level may also be used when input signals do not
have received SSM to pass to SSM to provide the output SSM when that input is
selected as reference.
Table 3-1 contains the accepted T1 and E1 standard SSM definitions.
Table 3-1. Standard SSM Definitions
SSM Description
Stratum 1
Traceability Unknown
Stratum 2
Stratum 3
Sonet Minimum Clock
Stratum 4
Don't Use For Sync
Reserved
SSMs and Input Modules
Certain Input modules can read received SSM which provides a Sync Quality Level
(SQL) indication for the signal. You may provision an SSM for each port and set the
fault condition to IGNORE, REPORT, ALARM, or FAIL if the received SSM is below
the provisioned value. The input signal is checked each second for a valid SSM,
and if none is received in the last second the module provides the provisioned
84 TSG-3800 User's Guide
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SQL T1
1 $04 $2
2 $08 $0
3 $0C $4
4 $10 $8
5 $22
6 $28
7 $30 $F
UA $40
E1 Abbreviation
PRS
STU
ST2
ST3
SMC
ST4
DUS
RES
12778474-002-2 Revision F – March 2004