Triple-Play Service Deployment

Chapter 8: Troubleshooting VoIP
Troubleshooting and Maintenance
Technicians will be called upon to perform two types of troubleshooting:
catastrophic failure and intermittent issues. When a
circuit is non-operational, the troubleshooting task is very similar
to turn-up.The technician will be able to terminate the circuit back
into a test device and begin the process of checking connectivity
to the local elements through pings, trace routes, and call
placement.The problem can be sectionalized to the CPE or carrier,
and remedied by the appropriate party.
Intermittent issues can present challenges. If the customer’s
phone system works reliably most of the time, the customer may
not allow the circuit to be taken out of service for testing. In this
instance, the technician must monitor the circuit to determine
which calls are experiencing trouble, when the trouble occurs, and
note environmental factors during the trouble occurrences.
Environment, in this case, refers to the traffic riding on the network
at the time of the failures. For example, other applications may use
router processing time or bandwidth that can cause calls to drop
or voice quality to transmit un-intelligibly to the receive end. The
only means to determine whether CPE traffic is the cause is to
monitor the whole circuit while the problem is occurring.
Network management and passive monitoring tools work well
for data networks but lack the detail needed to identify many
problems in VoIP networks. They also lack the ability to segment
problems to the CPE, customer network, or service provider network.
Furthermore, dispatching a technician with a comprehensive
network analysis instrument to the customer premises usually
indicates sending an engineer with more skills—at a higher expense.
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