Charging method, authentication method, charging device, and authentication device

A charging device, comprising:

• a storage device storing computer executable program codes;
• a processor, coupled with the storage device, wherein the program codes comprise instructions which, when executed by the processor, cause the processor to:
• receive a service unit request sent by an access device through an authentication device;
• calculate a granted service unit according to a current tariff;
• return a service unit answer to the access device through the authentication device when an overdraft monitoring condition is met according to the granted service unit and a tariff after a tariff switch point, wherein the service unit answer carries the granted service unit and a reporting time point that is determined according to the tariff switch point;
• receive a used service unit reported by the access device through the authentication device at the reporting time point;
• calculate a remaining service unit based on the granted service unit and the used service unit;
• and
• instruct, through the authentication device, the access device to perform a forcible offline operation when the remaining service unit will cause an overdraft.

An authentication device, comprising:

• a storage device storing computer executable program codes;
• a processor, coupled with the storage device, wherein the program codes comprise instructions which, when executed by the processor, cause the processor to:
• receive an access request sent by an access device, and send a service unit request to a charging device;
• receive a service unit answer that is returned by the charging device and carries a granted service unit;
• return an access response to the access device when the service unit answer carries an overdraft monitoring indication, wherein the access response carries the granted service unit and a reporting time point that is determined according to a tariff switch point;
• receive a used service unit reported by the access device at the reporting time point, and report the used service unit to the charging device;
• and
• receive a forcible offline instruction returned by the charging device, and instruct the access device to perform a forcible offline operation.