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Maintenance Description
9-58 Issue 3 June 2001
Unavailable Seconds (UAS) 9
A UAS is a second during which the OC-3 or OC-12 line is "unavailable." A line is
considered "unavailable" from the beginning of X consecutive SESs until the
beginning of Y consecutive seconds, none of which is severely errored. An X is
equal to 10 seconds or, in the case of a failure, the line signal failure. A Y is equal
to 10 seconds of no SES or line signal failure. If there is an unprotected circuit
pack failure, UAS are counted from within 1 second of circuit pack failure to within
1 second of circuit pack recovery. UAS are counted and thresholded
independently for the service and protection lines.
Line Protection Switch Counts 9
Line protection switch count is the count of the number of protection switches
FROM the working line. The count is independently counted and thresholded for
both the service and the protection line. This does not apply to main OC-N lines in
ring releases.
STS Pointer Justification Count (PJC) 9
This feature provides a TCA from a DDM-2000 shelf when the STS pointer
justification count in a performance bin exceeds a user provisioned threshold
value. STS PJCs for each SONET line interface are accumulated in 15 minute
and 24 hour performance monitoring bins. The TCA is sent via a TL1 autonomous
message to the OS and is available through CIT and TL1 PM reports. PJCs are
not accumulated during one second intervals in which an STS-1 is in the LOP or
AIS state.
For each SONET line interface, the system accumulates counts from only one
STS-1tributaryduringa1secondmonitoringinterval.Excessivepointer
justifications indicate a frequency error in the network or other potential
synchronization problem. For example, a frequency error could be caused by a
shelf in holdover or by a frequency offset in an external timing reference in
networks with more than one shelf externally timed. The TCA can be provisioned
in the frequency offset range from approximately .01 ppm to 10 ppm by setting a
threshold for the pointer justification count equivalent to the frequency offset.
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