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Maintenance Description
9-48 Issue 3 June 2001
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 PJC equivalent to the frequency offset.
STS-1 Path Parameters 9
Performance Monitoring Enabling 9
â– OC-3 Interfaces
For systems using manual STS-1 cross-connections, monitoring is initiated
only when an STS-1 cross-connection is made and the channel is in the IS
state. Parameters continue to be available in reports and generate
appropriate TCAs until the STS-1 cross-connection is deleted. Removal of
a circuit pack without removal of the cross-connection are reported as
"unavailable time."
For systems using manual VT1.5 cross-connections, 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. This applies to STS-1
paths on both OLIU and STS1E low-speed circuit packs. Parameters
continue to be available in reports and generate appropriate TCAs until the
last VT1.5 signal associated with that STS-1 cross-connection is deleted.
â– EC-1 Low-Speed Interfaces
For EC-1 low-speed interfaces, collection of STS-1 path parameters are
initiated only when a slot is equipped with an STS1E circuit pack set for
low-speed and an STS-1 or VT1.5 cross-connection is made.
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. Beginning with R13.0, STS-1 path performance information is
extended to monitor all incoming OC-n and EC-1 low-speed interfaces to an NE
independent of whether the STS-1 terminates on that NE.
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
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