363-206-305
Maintenance Description
9-30
Issue 3 June 2000
Severely Errored Seconds (SES)
9
A severely errored second is a second in which 12 or more for OC-1, or 32 or
more for OC-3, or 124 or more for OC-12, B2 parity violations are detected or one
in which a loss of signal, loss of frame or line AIS occurs. An unavailable second is
not counted as a severely errored second. Severely errored seconds are counted
and thresholded independently for service and protection lines.
Unavailable Seconds (UAS)
9
An unavailable second is a second during which the OC-1/OC-3/OC-12 line is
"unavailable." A line is considered "unavailable" from the beginning of X
consecutive severely errored seconds until the beginning of Y consecutive
seconds, none of which is severely errored. X is equal to 10 seconds or, in the
case of a failure, the line signal failure. Y is equal to 10 seconds of no severely
errored seconds or line signal failure. Unavailable seconds are counted and
thresholded independently for OC-1/OC-3/OC-12 interface service and protection
line.
Line Protection Switch Counts
9
Line protection switch counts is the count of the number of protection switches
FROM the working OC-3/OC-12 interface line. The count is independently
counted and thresholded for both the service and the protection line.
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-1 tributary during a 1 second monitoring interval. Excessive pointer
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 PJC equivalent to the frequency offset.
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