MINI-LINK TN R3 ETSI
3.10.3 Status
The synchronization status functions are used to propagate and signal the
quality level of the SEC to the node interfaces.
The Synchronization Status Propagation logic distributes synchronization
status for transmission of synchronization status messages (SSM) on interfaces
supporting and configured for this.
The Squelch logic distributes information on poor or lost synchronization input
to interfaces that cannot signal synchronization status messages, for these to
send AIS. From management squelch can be enabled/disabled for the whole
node as well as individually for all outgoing SDH and PDH interfaces.
Towards protected interfaces, squelch are configured onto the protected (1+1)
interface, not on the individual interfaces.
The squelch ‘Wait To Restore Time’ is also configurable per interface.
When protected interfaces are nominated to be synchronization sources
candidates they should have their ‘Wait To Restore Time’ set longer then the
‘Hold Off Time’ of the protected interface, to avoid unnecessary switching of
synchronization sources.
9745
Free Running
Synchronization Logic
Squelch
E1
1+1 E1 SNCP
STM-1
MSP 1+1
2 MHz
Interfaces
E1
Interfaces
STM-1
Network
Synchronization
Synchronization
Status Propagation
Selection
Loop Timing
or NE Timing
T1
T2
T3
T0
T0, T1, T2 and T3:
ITU-T SDH Equipment Clock (SEC) names
Logic
SEC
Status
Figure 51 MINI-LINK TN Synchronization functions
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/1555-CSH 109 32/1-V1 Uen B 2007-09-14
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