s on general statistics on most popular services, feedbacks/satisfaction levels from customer, annual or quarter wise financial reports of the company, and SO on. The next important activity in assurance process is trouble handling. This involves customer problem handling, service problem management and network Fundamentals of EMS, NMS and OSS/BSS Customer support Billing and center (CSC) fulfillment Trouble ticketing Verification Network operations center (NOC) Provisioning ((g)) Network elements Figure 20.10 Trouble handling. trouble handling processes corresponding to a customer, service and network layers, respectively (see Figure 20.10). Let us consider a typical workflow of how an issue raised by a customer gets handled in the assurance process. The steps are: 1. Customer calls up the customer support center (CSC) and reports an issue about the service offered along with details on the customer account. 2. The CSC will verify the account details of the customer with the billing and fulfillment modules. 3. Next the specific problem and the history of the problem is documented with the trouble ticketing module. 4. CSC will then try to fix the issue (4a) or hand off the call to technical support (4b) in the network operations center (NOC). 5. Assuming CSC hands off the call, the NOC will interact with the customer and try to do the following checks based on professional support expertise and diagnostic tools available: a. Identify if this needs to be fixed at service level. b. Identify if this is caused by a problem with the network. C. Determine if this problem is caused due to a problem already identified and tracked by an existing trouble ticket. OSS/BSS Functions Check if a similar trouble was previously reported and an already existing fix can be applied. If an immediate fix cannot be applied the ticket is assigned to an appropriate team and the customer is given a ticket number that can be used to track the status of the fix. 6. After the issue is isolated and fixed, NOC informs the CSC to close the trou