Patent ID: 8156016

Claim:
A system for accounting, comprising an AAA client and an accounting processing unit; wherein the AAA client comprises a QoS change detection unit and an accounting information unit; wherein, the QoS change detection unit is adapted to detect a message received by the AAA client during a session and send an initiation instruction to the accounting information unit as detecting a QoS change notification; and, the accounting information unit is adapted to obtain and save the accounting information as receiving the initiation instruction; wherein, the accounting processing unit is adapted to receive the accounting information sent by the AAA client and implement an accounting operation for the session; wherein the accounting processing unit comprises: a prepaid service accounting processing unit, adapted to settle a cost according to an old QoS comprised in the accounting information, derive a tariff from a new QoS comprised in the accounting information, calculate a new quota according to the new tariff and send the new quota to the AAA client, wherein the AAA client is located in a mobile station.