• ODU Tx cable IF synthesizer not locked
•10
-6
BER (user selectable wrap and unwrap options)
• RAC plug-in is missing
• RAC software load failure
Fiber (DAC 155oM) Links
Conditions for ring wrapping:
• Loss of SDH/SONET frame
• DAC 155oM plug-in is missing
• DAC 155oM software load failure
Wrap and Unwrap Times
The wrapping process is performed without any participation of the alarmed
RAC or DAC 155oM (or potentially failed RAC/DAC in the instance of a silent
transmitter failure).
Ring wrapping and unwrapping is not hitless:
• The service restoration times (detection, switching and recovery) for a ring
wrap is not more than100 ms.
• The revertive switch command for return to normal service is initiated after the
relevant alarms on the failed link have been cleared for a period set by the
Error-Free Timer (default 5 minutes), or by the optional Delay Ring Unwrap
Timer, which sets a time of day for an unwrap. Full restoration of normal traffic
(unwrapped) on the ring occurs within 100 ms of receipt of the revertive switch
command.
Unwrap Timers
An Error-free Timer in the Protection configuration screen sets the period of
error-free operation needed prior to initiation of an unwrap. When a wrap has
occurred this timer counts down towards an unwrap as soon as all wrap
conditions are cleared. The count begins anew should a wrap condition re-occur
during the countdown. The time options are 10 seconds, or 1, 5, or 10 minutes. 5
minutes is default (recommended).
A Delay Ring Unwrap timer in the Protection configuration screen allows
setting of a time of day when an unwrap will occur providing all wrap conditions
have been cleared for a period not less than that set in the Error-free Timer. This
timer has a 1-hour window; if the conditions which caused the wrap are not
cleared by the Error-free Timer during this window, then Delay Ring Unwrap
resets for the same time the following day.
The System/Controls screen provides a countdown timer to indicate the time to
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