Optimization of Flow Control Mechanism in iSCSI

This paper presents a method to improve the performance of the storage network. There are two parameters which are very important to the performance of the storage network. They are congestion window in the TCP layer and max burst length in the iSCSI layer. They both have the similar function that controls the flow of the network. When the network is busy, they both become smaller and vise versa. But because the TCP layer is lower than the network storage layer, it can detect the network state earlier. The time to change these parameters is different and the max burst length is always changed later. So there is a period in which the max burst length is not match the network state perfectly which can diminish the utilization of network bandwidth. The method which changes these two parameters simultaneously is presented in this paper and its results are proved by the experiments. This optimization can be applied in most of the network storage system in the market.