<p><b>Overview</b><br/></p><p>Online charging is a charging mechanism, where charging information can affect, in real-time, the service rendered. The charging request as well as the response is handled in real-time through the use of real-time guiding to (finding of) customer and price plan, real-time rating and real-time balance-management of monetary and non-monetary (e.g. free-units) balances and/or allowances.<br/></p><p><br/></p><p>A request is sent by the network service-controller to the online-charging application in real-time (usually through an IP-socket) and a response is returned. The service-controller can decide, based on the response, whether to render the service and usually control the service characteristics (quality, etc.) prior to providing it or during the session.<br/></p><p><br/></p><p>Note: The relation of online and offline is subject for further study in future TAM version.<br/></p><p><br/></p><p><b>Functionality</b><br/></p><p><b>The Online Charging Application is responsible for:</b><br/></p><p><ul><li><b>Real-time Rating</b>: perform real-time rating of the charge request based on all parameters of the request (type, quantity, etc.), all parameter of the customer/subscriber (price plans, accumulated usage, etc.) and other parameters (time-of-day, etc.). The same request may be rated differently for different subscribers based on their purchased offers. (Refer to the Product/Service Rating application)</li><br/></p><p><li><b>Service-consumption reservation and authorization</b> authorizes the request coming from the service-controller based on the customer and subscriber eligibility for the service (e.g. based on customer-hierarchy and purchased offers) and on the current balance available.</li><br/></p><p><li><b>Use of customer billing hierarchy</b>: each subscriber can be part of a customer-hierarchy tree of unlimited depth and size. Subscribers in the hierarchy may share balances, price plans and discounts. Customer hierarchies are commonly used for corporate customers who share allowances and balances</li><br/></p><p><li><b>Advice of Charge/Advice of Rate:</b> provide, in real-time, an advice of the expected charge for a specific usage request. The advice is based on all parameters of the request (type, quantity, etc.), all parameter of the customer/subscriber (price plan, accumulated usage, etc.) and other parameters (time-of-day, etc.). The advice is usually based upon performing a full Rating process for the request.</li><br/></p><p><li><b>Balance Management</b>: hold, calculate, apply policies and provide functionality / interfaces for the account balances of a customer and/or a subscriber.</li><br/></p><p><li><b>Balance containers:</b> hold and maintain the different balances that a customer and/or a subscriber may have. These include, but not limited to:</li><br/></p><p><li>Monetary balances</li><br/></p><p><li>Prepaid balances</li><br/></p><p><li>Postpaid balances (in conjunction with an Account-Receivables (AR) application)</li><br/></p><p><li>Non-monetary balances and allowances (e.g. free minutes, WAP-only quota, etc.)</li><br/></p><p><li>Shared balances: Monetary or Non-monetary (e.g. between subscribers in a hierarchy)</li><br/></p><p><li><b>Balance management policies: </b>allow the definition of policy per balance or balance-type. Policies include:</li><br/></p><p><li>Minimum Allowable Balance limit (e.g. balance must remain above zero)</li><br/></p><p><li>Balance expiration dates</li><br/></p><p><li>Balance thresholds actions and notifications</li><br/></p><p><li>Roll-over and cyclic policies</li><br/></p><p><li><b>Balance-management operations</b>: allow different operations to be performed on the managed balance. Operations include:</li><br/></p><p><li>Reserve amounts: reserve amount from any balance for any session. Unused reservations are credited back into the balance when the session is released</li><br/></p><p><li>Charge amounts: charges that are persisted into the balance</li><br/></p><p><li>Credit/Debit operations</li><br/></p><p><li>Balance Query</li><br/></p><p></ul><br/></p><p>Note: Balance management for offline charging is also need to be addressed in the offline charging context.<br/></p><p><ul><li><b>Real-time Charging:</b> apply charges (rated requests) and taxes in real-time using the balance-management functionality. Charging can be done by units or by amount</li><br/></p><p></ul><br/></p><p>Non-functional aspects of the Online-Charging application include:<br/></p><p><ul><li><b>Multi-session support</b>: Online charging applications must be able to support multiple simultaneous sessions for the same subscriber and/or for the same customer. The simultaneous sessions are able to use the same balances while adhering to the balance-limit policy defined (achieved using reservations)</li><br/></p><p><li><b>Prepaid-Postpaid Convergence</b>: allow for prepaid subscribers and postpaid subscribers to be served by the same Charging application, and use shared balances and price plans.</li><br/></p><p><li>Allow replenishment (top-up, recharge) of prepaid balances from postpaid accounts</li><br/></p><p><li>Allow spending-limits and credit-control to be enforced on postpaid accounts</li><br/></p><p><li>Split charging: allow splitting usage-charges between prepaid and postpaid balances based on any parameter For example: a subscription where voice calls are postpaid by a corporate and content is consumed from the employee prepaid balance.</li><br/></p><p><li><b>High Availability</b>: Online-Charging application should provide Carrier grade availability with 99.999% application up-time</li><br/></p><p><li><b>Low Latency</b>: responses to requests should be given in very low latency, usually below 25ms from request to response</li><br/></p><p><li><b>High Throughput</b>: The Online-Charging application must support the maximum request and events throughput required during the busiest hour of the year without throttling or rejecting any request.<br/></li><br/></p><p></ul><b>Supported Contracts</b><br/></p><p><b>Exposed Contracts</b><br/></p><p><ul><li>Service Control Point (SCP)</li><br/></p><p><li>SCP-like Network-Elements (NE)</li><br/></p><p><li>Intelligent Network (IN)</li><br/></p><p><li>Replenishment manager</li><br/></p><p><li>Customer Relationship Management (CRM) for Balance queries  and similar activities</li><br/></p><p><li>Customer Management and Account-Receivables for Balance adjustments</li><br/></p><p><li>IVR (Interactive Voice Response) for Balance queries  and similar activities</li><br/></p><p><li>Customer management for Create/Maintain/Delete customers, accounts and price plans</li><br/></p><p><li>Invoicing</li><br/></p><p><li>Account Receivables</li><br/></p><p><li>Data Warehouse<br/></li><br/></p><p><li><b>Consumed Contracts</b></li><br/></p><p><li>Product Catalog</li><br/></p><p><li>Provisioning</li><br/></p><p><li>Notifications and messaging</li><br/></p><p></ul><br/></p>