363-206-295
Maintenance Description
9-34
Issue 1
December 1997
OC-3 and OC-12 Line Parameters
9
Performance Monitoring (PM) Enabling
9
Collection of line parameters are initiated when a slot is equipped with an OLIU
circuit pack. Parameters continue to be available in reports and generate
appropriate TCAs until the OLIU is removed and the
update
command or the
UPD/INIT button is pressed.
Line Coding Violations (B2 Parity)
9
To monitor the performance of the OC-3 and OC-12 lines, 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. The contents of the three or 12 line B2
parity violation counters associated with the OC-3 and OC-12 line are added to
form a composite B2 parity violation count. CVs 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 the service and protection lines.
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 32 for
OC-3, or more than one and less than 124 for OC-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 the service
and protection lines.
Severely Errored Seconds (SES)
9
A SES is a second in which 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. A UAS is not counted as a SES. SESs are counted and thresholded
independently for the service and protection lines.
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
