Lucent Technologies DDM-2000 OC-3, User & Service Manual

Page: 566 / 2536

363-206-285
Maintenance Description
9-44 Issue 3 June 2001
Additionally, each DS1PM circuit pack measures the near-end performance of the
incoming DS1, allowing the service provider to determine if a good DS1 signal
was received from the customer before transporting it through the network. This
information can then aid in sectionalizing any reported performance problems.
The DS1PM circuit pack can also provide this same near-end information for SF
formatted (sometimes known as "D4 framing") DS1 services, but complete end-to-
end performance verification is limited due to the lack of the PRM in the SF
format.
DS3 Performance Monitoring 9
DS3 Path PM 9
With the BBG4B DS3 and BBG20 TMUX circuit packs, the DDM-2000 OC-3
Multiplexer provides three DS3 path PM options: P-bit (parity bit), adjusted F&M
bit (frame and multiframe 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 9-5).
P-Bit 9
When provisioned for P-bit, the system calculates and provides counts of DS3
CV-P, ES-P, SES-P, and UAS-P incoming from the fiber and DSX. Quarter-hour
and current day registers are provided with provisionable TCAs on a per-shelf
basis. SEFS are also monitored.
Because P-bits can be corrected at nodes provisioned for 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
and provides estimated counts of DS3 adjusted F&M bit CVs, ESs, SESs, and
UASs incoming from the fiber and DSX. Quarter-hour and current day registers
are provided with provisionable TCAs on a per-shelf basis. SEFS are also
monitored.