363-206-305
Maintenance Description
Issue 3 June 2000
9-31
STS-1 Path Parameters
9
Performance Monitoring Enabling
9
STS-1 path performance monitoring is initiated only when the first VT1.5 cross-
connection associated with that STS-1 signal is made and the VT channel is in the
IS state. Parameters continue to be available in reports and generate appropriate
threshold crossing alerts until the last VT1.5 cross-connection is deleted.
STS-1 Path Coding Violations (B3 Parity)
9
To monitor the performance of the STS-1 path, the "B3" byte in the STS-1 path
overhead is written when the path is originated and checked for errors when the
path is terminated. The B3 coding violation counter is incremented for each error
detected. Up to eight errors per STS-1 frame can be detected in each STS-1
synchronous payload envelope (SPE). B3 coding violations are counted and
thresholded separately for each STS-1 path terminated by the system. Coding
violations are not counted during seconds that contain a line AIS, loss of signal,
loss of frame, loss of pointer, STS path AIS, or during an unavailable second
(UAS).
Errored Seconds (ES)
9
An "errored second" is a second in which one or more B3 parity violations are
detected. Seconds that are unavailable seconds are not counted as errored
seconds. An errored second "type A" is a second in which exactly one B3 parity
violation is detected. An errored second "type B" is a second in which more than
one and less than nine B3 parity violations are detected. All three of these
parameters are counted and thresholded independently for each STS-1 path
terminated by the system.
Severely Errored Seconds (SES)
9
A severely errored second is a second in which nine or more B3 parity violations
are detected. Severely errored seconds are counted and thresholded separately
for each STS-1 path terminated by the system. An unavailable second is not
counted as a severely errored second.
Unavailable Seconds (UAS)
9
An STS-1 path 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
STS signal failure. Y is equal to 10 seconds of no severely errored seconds or
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