Method for controlling quality of service of internet small computer system interface iSCSI

The invention discloses a method for controlling quality of service (QoS) of an Internet small computer system interface (iSCSI) for controlling the quality of service between an initiator device and a destination device, which comprises the following steps: presetting two variables of bucket and bucket_used; receiving a protocol data unit which is transmitted from connection; if the protocol data unit carries or requests data, accumulating the length of the data which is carried or requested by the protocol data unit within the second, storing the data in the variable bucket_used; judging whether the variable bucket_used is greater than the variable bucket, if so, suspending a quality-of-service control object of the current iSCSI and not accepting a new protocol data unit till the present second is finished; and otherwise, handing the protocol data unit over to an iSCSI protocol data unit processor for continuous execution. The method can control the QoS of different iSCSI quality-of-service control objects through the uniformly controlled granularity at an iSCSI service layer, so that the complexity of controlling the quality of service is greatly reduced.