Synchronization and Redundancy
A system supporting SSM/ESMC can be provisioned for either Option 1 or Option 2 (SDH/
SONET) messages and can translate between equivalent QL message for either option.
Under upstream network failure conditions the synchronization function can take appropriate
action based on the SSM and pre-set priorities and selects an alternate synchronization feed. This
can be another network feed or an external feed.
SSM allows equipment to autonomously provision and reconfigure (by reference switching) their
synchronization references, while helping to avoid the creation of timing loops. These messages
allow synchronization reconfigurations of network synchronization trails when timing is
distributed in both directions around a ring.
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