610
14 Basic Measurement and Monitoring Techniques
• Measures center wavelength accuracy to better than ±50 pm
• Determines OSNR with a 35-dB dynamic range to a ±0.1-dB accuracy.
14.7.5 Detecting Network Faults
Faults in a network, such as physical cuts in a fiber transmission line or failure of a
circuit card or optical amplifier, can cause portions of a network to be inoperable.
Because network faults can result in system downtime or unacceptable network
degradation, fault management is one of the most widely implemented and essential
network management functions. As Fig. 14.20 illustrates, fault management involves
the following processes:
Network fault management system
Fault
management
console
• View of network map
• Alarm surveillance
• Alarm correlation
• Monitoring of
• Fault isolation
• Fault resolution
Alarm
log
Trouble ticket
database
• Monitoring of
• Fault probes
• Fault alarms
• Fault isolation
• Issuing trouble tickets
• Logging of
• Alarms
• Trouble tickets
Alarms
Resolution
by technician
Automatic
resolution
Trouble
tickets
Probes
?
Fig. 14.20 Functions and interactions of a network fault management system