14.7 Optical Performance Monitoring
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• Detecting faults or degradation symptoms. This can be done with alarm surveillance, which involves reporting alarms that may have different levels of severity
and indicating possible causes of these alarms. Fault management also provides
a summary of unresolved alarms and allows the network manager to retrieve and
view the alarm information from an alarm log.
• Determining the origin and possible cause of faults either automatically or through
the intervention of a network manager. To determine the location or origin of
faults, the management system might use fault-isolation techniques such as alarm
correlation from different parts of the network and diagnostic testing.
• After the faults are isolated, the system issues trouble tickets that indicate what the
problem is and possible means of how to resolve the fault. These tickets go to either
a technician for manual intervention or an automatic fault-correction mechanism.
When the fault or degradation is corrected, this fact and the resolution method are
indicated on the trouble ticket, which then is stored in a database.
• After the problem has been fixed, the repair is operationally tested on all major
subsystems of the network. Operational testing involves requesting performance
tests, tracking the progress of these tests, and recording the results. The classes of
tests that might be performed include echo tests and connectivity examinations.
A basic factor in troubleshooting faults is to have a comprehensive physical and
logical map of the network. Ideally this map should be part of a software-based
management system that can show the network connectivity and the operational
status of the constituent elements of the network on a display screen. With such a
map, failed or degraded devices can be viewed easily and corrective action can be
taken immediately.
14.8 Optical Fiber Network Performance Testing
The evolution of optical fiber communication technology has resulted in highly
reliable telecom transmission systems for applications that include high-capacity
long-distance links and optical metro, access, and in-building networks. A wide
variety of communication protocols, data modulation formats, performance monitoring techniques, and performance testing methods have been devised to keep these
systems running smoothly and reliably. In terms of performance testing, the major
measurement methods include the bit-error rate (BER), the optical signal-to-noise
ratio (OSNR), the Q factor, timing jitter, and the optical modulation amplitude. This
section provides an overview of these techniques. Further extensive details can be
found in the literature [13–20].
611
• Detecting faults or degradation symptoms. This can be done with alarm surveillance, which involves reporting alarms that may have different levels of severity
and indicating possible causes of these alarms. Fault management also provides
a summary of unresolved alarms and allows the network manager to retrieve and
view the alarm information from an alarm log.
• Determining the origin and possible cause of faults either automatically or through
the intervention of a network manager. To determine the location or origin of
faults, the management system might use fault-isolation techniques such as alarm
correlation from different parts of the network and diagnostic testing.
• After the faults are isolated, the system issues trouble tickets that indicate what the
problem is and possible means of how to resolve the fault. These tickets go to either
a technician for manual intervention or an automatic fault-correction mechanism.
When the fault or degradation is corrected, this fact and the resolution method are
indicated on the trouble ticket, which then is stored in a database.
• After the problem has been fixed, the repair is operationally tested on all major
subsystems of the network. Operational testing involves requesting performance
tests, tracking the progress of these tests, and recording the results. The classes of
tests that might be performed include echo tests and connectivity examinations.
A basic factor in troubleshooting faults is to have a comprehensive physical and
logical map of the network. Ideally this map should be part of a software-based
management system that can show the network connectivity and the operational
status of the constituent elements of the network on a display screen. With such a
map, failed or degraded devices can be viewed easily and corrective action can be
taken immediately.
14.8 Optical Fiber Network Performance Testing
The evolution of optical fiber communication technology has resulted in highly
reliable telecom transmission systems for applications that include high-capacity
long-distance links and optical metro, access, and in-building networks. A wide
variety of communication protocols, data modulation formats, performance monitoring techniques, and performance testing methods have been devised to keep these
systems running smoothly and reliably. In terms of performance testing, the major
measurement methods include the bit-error rate (BER), the optical signal-to-noise
ratio (OSNR), the Q factor, timing jitter, and the optical modulation amplitude. This
section provides an overview of these techniques. Further extensive details can be
found in the literature [13–20].