 or connectivity that failed, and monitoring performance records are all covered as components in the network management part of assurance. Service assurance is more on monitoring the service KPIs (key performance indicators) to ensure that the intended service quality is achieved. The numbers of outages, the maximum transfer rate, the number of fault scenarios are all indicators of the quality of service. At the customer level, the assurance process is more targeted to meeting an SLA. The parameters specified in SLA are moni- tored and any slippage in the SLA needs to be communicated to the customer and compensation. Customer retention and loyalty are also a part of assurance process. Sending reports, mail alerts on schedule maintenance, providing incentives and discounts, quick closure of troubles reported all help to improve customer satisfac- tion. A well-defined assurance process can be a key differentiator in increasing a service provider's competitiveness. The network operations are monitored and maintained by administrators work- ing from the network operations center (NOC; see Figure 20.8). To control and maintain the network activity there can be multiple NOCs for a single service pro- vider. The device status data, alarms generated, performance records, and critical element failure information are all collected by the network management system at the NOC. The records collected by the NMS are used to generate reports that will be used for network planning and service management. The fault information from NMS can be aggregated to provide service level fault data. So a trouble condition in an offered service can be mapped to the associated network and further drilled down to the specific element that caused the issue. The NOC professionals have to continuously monitor the critical performance and fault information required to ensure smooth network operation. The management solution in NOC deals with: Collection: The data from the network elements has to be collected. All fault, configuration, accounting,