Patent ID: 8732380

Claim:
A system using a multipath in a Serial Attached SCSI (SAS) network, comprising: a SAS initiator; a SAS target comprising a plurality of ports; and a SAS expander connected to the SAS initiator and-configured to form a plurality of paths to the SAS target such that each path is connected to one port from said plurality of ports of the SAS target, wherein the SAS expander comprises: a storage unit configured to store, for each of the plurality of paths to the SAS target, a data transfer amount, wherein the data transfer amount is an amount of data transferred between the SAS initiator and the SAS target through said path; a receiving unit configured to receive a Serial SCSI Protocol (SSP) command frame from the SAS initiator; and a determination unit configured to select one path from the plurality of paths to the SAS target to satisfy the SSP command frame and achieve load distribution; a transmitting unit configured to transmit the SSP command frame to the SAS target through the selected path; an adding unit configured to add a data length amount included in the SSP command frame to the data transfer amount for the selected path; and a subtracting unit that subtracts the data length amount based on one of time and a received SSP response frame.