VeEX MPA User Manual page 495

MPA_e_manual_D07-00-129P_RevA00
Protocol Tabs
The service disruption measurements show a granular accuracy of 1 frame duration.
For all SDH rates one frame is roughly .125 ms (125 µs)
Test Service Disruption functions include:
•
Action (State) - Starts and stops Service Disruption mode. If an event occurs,
the protection switch time will appear in both seconds and frames present. The
results will not include the number of good frames, but the number of errored
frames that occur before the first good frame. This is based on the previously
selected criteria for the consecutive time and frame requirements. The unit
begins monitoring the incoming signal for a service disruption measurement
event as soon as one of the following State options is selected:
Single APS - Monitors for a single service disruption event. Seconds and
frames are reported and the State returns to Inactive.
Continuous APS - Constantly monitors for service disruption events, and
updates the seconds and frames reported.
Stop APS - Stops service disruption monitoring. The State returns to
Inactive.
•
Protection Switch Criteria - Determines the type of alarm, error, or pattern
event that is used as a trigger to generate service disruption activity in your
network. The unit monitors the incoming signal for the specified event. If it
occurs, its duration in both seconds and frames is measured and logged.
For all SDH processors the Protection Switch Criteria include: B1, OOF, MS-
AIS, AU-AIS, TU-AIS, and PRBS (Bit Errors and Loss of Pattern Sync).
•
Good Time - This function allows you to enter the time-duration (in milliseconds)
of consecutive error-free frames to elapse before Protection Switch
measurements stop accumulating.
For all SDH processors the range is 0.125 to 2047.875 ms, and is entered
using a keypad.
•
Good Frames - This function allows you to enter the number of consecutive
error-free frames to occur before Protection Switch measurements stop
accumulating.
The range is 1 to 16383 frames, and is entered using a keypad.
•
Switch MilliSecs - Indicates the Current (most recent), Average, Minimum and
Maximum durations (in milliseconds) that it took for the service disruption events
(errored frames) to occur.
•
Switch Frames - Indicates the Current (most recent), Average, Minimum and
Maximum number of errored frames received during the service disruption event.
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