Performance Monitoring; T1 Line Performance Monitoring; Dds Line Performance Monitoring - Zhone IMACS 8000 User Manual

System Testing and Diagnostics
6.6

Performance Monitoring

The Integrated Access System provides non-intrusive performance monitoring of T1 lines and
DDS circuits that terminate on OCU-DP cards. This capability is built into the system
software and does not require any special options or expensive external equipment.
6.6.1

T1 Line Performance Monitoring

Performance monitoring, statistics gathering and performance reporting of T1 facilities is
supported in this system. In ESF format, CRC errors, Out-of-Frame errors, and Controlled
Slips are combined to provide line quality and performance statistics in accordance with
industry standards. In D4 format, Bipolar Violations (BPVs) are used instead of CRC errors.
The performance statistics are gathered and displayed in fifteen-minute intervals for the
preceding twenty-four hours. They include Errored Seconds, Unavailable Seconds, Severely
Errored Seconds, Bursty Errored Seconds, Loss Of Frame Count, and Slipped Seconds.
In ESF mode, these statistics are available to the system operator as well as to the carrier or
service provider over the embedded 4 Kbps Facilities Data Link (FDL). Each ESF T1 facility
can be independently programmed to support framing according to the AT&T 54016 standard
or the ANSI T1.403 standard or both simultaneously. Additionally, for each T1 in the system,
the operator may select an error rate threshold (from 10E-4 to 10E-9) which, if exceeded, will
cause the system to generate an Excessive Error Rate (EER) alarm.
While using transcoder operations for T1 that involve downstream tributaries, setting EER-3
to "report" will cause an alarm to appear on the local system when T1 transmission errors
exceed 10e-3 (1 in 1000). The local EER-3 alarm will identify the effected WAN link (i.e.,
W1-1) and take it out of service. Simultaneously, the downstream tributary will receive an AIS
alarm to warn them of the condition.
6.6.2

DDS Line Performance Monitoring

The two port OCU-DP card supports two methods of non-intrusive error correction. The first
is Majority Vote and applies to lower data rates such as 2.4, 4.8 and 9.6 Kbps. The other is the
BCH method and applies to data rates of 19.2 Kbps and 56 Kbps.
If an OCU-DP port has error correction enabled, then the system will collect and display
statistics on the performance of the circuit. Performance statistics include incoming (from the
T1 network) and outgoing (to the 4-wire DDS circuit) Errored Seconds, Severely Errored
Seconds and Consecutive Severely Errored Seconds and are displayed in one-hour intervals
for the preceding twenty-four hours.
Reference Guide
Performance Monitoring
6-11