363-206-295
Maintenance Description
Issue 1
December 1997
9-29
— DS1 (DDM-2000 OC-3 Only) — DS1 near-end path is monitored for
SF framing and both near-end and far-end paths are monitored for
ESF framing. The data is displayed in ES-P, SES-P, and UAS-P
categories. CV-P is also displayed.
— DS3 — DS3 path incoming from the fiber (high-speed side) is
monitored for both P-bits and F&M bits and the data is displayed in
CV-P, ES-P, SES-P, and UAS-P registers. In addition, severely
errored frame seconds (SEFS) are also monitored and displayed.
DS3 path incoming from the DSX-3 (low-speed side) is also
monitored, in addition to monitoring the path from the fiber, for both
P-bits and F&M bits. The same registers are also displayed for the
data from the DSX-3. DS3 path from both the fiber and the DSX-3
are monitored for C-Bits and are displayed in the same registers as
above. The far-end data (FEBE bits) is monitored and displayed as
well.
DS3 Performance Monitoring (PM)
9
DS3 Path PM
9
DDM-2000 OC-12 provides three DS3 path PM options using the BBG11B DS3
circuit pack: P-bit (parity bit), adjusted F&M bit, and C-bit. The options are
selected using a command that also sets the PM mode to "on" (default) or "off",
which enables or disables the monitoring and reporting of DS3 path PM data (see
Table 9-4).
P-Bit
9
When provisioned for P-bit, the system calculates and provides counts of DS3
P-bit coding violations (CV), errored seconds (ES), severely errored seconds
(SES), and unavailable seconds (UAS) incoming from the fiber and DSX. Quarter-
hour and current day registers are provided with provisionable threshold crossing
alerts (TCAs) on a per shelf basis. SEFS are also monitored.
Because P-bits can be corrected at nodes provisioned for violation monitor and
removal (VMR) along a DS3 path, the DS3 P-bit PM data may not provide a
complete report of the end-to-end DS3 path errors.
Adjusted F&M Bit
9
Adjusted F&M bit PM provides an alternative method for determining and
accumulating DS3 path performance data based on an error estimation technique
using errors on the F&M framing bits to approximate the actual error counts in the
DS3 path payload. F&M bits are not corrected at nodes provisioned for VMR
along a DS3 path. When provisioned for adjusted F&M bit, the system calculates
