s: Based on the subscription taken up by the customer there is a limit set on the usage of resources, for example, disk space, network band- width, call duration, services offered, and SO forth. Converged billing: A single service is realized using multiple network ele- ments. Traditionally accounting information is collected from all the NEs and a single bill is generated. With converged billing the customer can have multiple services and still get a consolidated billing for all the services. Fundamentals of EMS, NMS and OSS/BSS Audits: Accounting is a critical aspect of business and forms the revenue for physical network and service offered. Hence billing records and reports are handled carefully in management applications. Schedule audits and reports check the correctness of information and helps in archiving of data. An inter- nal scheduler can perform report generation. Reports give consolidated data that form input to business and technical planning. Fraud reporting: Fraud management in telecom has evolved to be an inde- pendent area of specialization and there are applications to detect fraud that are delivered independently without being part of a management applica- tion. As part of the initial definitions of ITU-T, fraud reporting was part of accounting. Some of the telecom frauds are: Subscription Fraud, Roaming Subscription Fraud, Cloning, Call-Sell Fraud, Premium Rate Services (PRS) Fraud, PBX Hacking/Clip-on Fraud, Pre-paid Fraud, Internal Fraud, and SO on. The account management system should be such that it can interface to all types of accounting systems and post charges. 3.5 Performance Management Performance management involves evaluation and reporting the behavior and effectiveness of network elements by gathering statistical information, maintaining and examining historical logs, determining system performance, and altering the system modes of operation. Network performance evaluation involves: Periodic tests to measure utilization, throughput, latency availability, and jitter Identifying key