OCS is a specialized communications function that allows a service provider to charge a user for services in real-time. The OCS handles the the subscribers account balance, rating, charging transaction control and correlation. With the OCS, a telecom operator ensures that credit limits are enforced and resources are authorized on a per transaction basis.
Traditional online charging systems charge the customer after a service is rendered, whereas the OCS charges as services are rendered. OCS is more flexible than Intelligent Network (IN) prepaid solutions.