363-206-285
Maintenance Description
9-56 Issue 3 June 2001
Line Coding Violations (B2 Parity) 9
To monitor the performance of the OC-1 line, the line BIP-8 (B2 parity) is
calculated, written, and checked for errors. The line B2 parity violation counter is
incremented for each line BIP error detected. Each line BIP-8 can detect up to
eight errors per STS-1 frame. CV-Ls are not counted during seconds that contain
a line AIS, LOS, LOF, or during a UAS. The B2 parity violations are counted and
thresholded independently for each OC-1 line.
Errored Seconds (ES) 9
An "errored second" is a second in which one or more B2 parity violations are
detected. An ES "type A" is a second in which exactly one B2 parity violation is
detected. An ES "type B" is a second in which more than one and less than 12 B2
parity violations are detected. Seconds that are UAS are not counted as ES. A
second that contains a line AIS, LOS, LOF or is a UAS is not counted as a type A
or type B ES. All three of these parameters are counted and thresholded
independently for each OC-1 line.
Severely Errored Seconds (SES) 9
A SES is a second in which 12 or more B2 parity violations are detected or one in
which a LOS, LOF or line AIS occurs. A UAS is not counted as a SES. SES are
counted and thresholded independently for each OC-1 line.
Unavailable Seconds (UAS) 9
A UAS is a second during which the OC-1 line is "unavailable." A line is
considered "unavailable" from the beginning of X consecutive SES 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 SES or line signal failure. UAS are counted and thresholded
independently for each OC-1 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
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