<p>Each of SAS expanders ("expander(s)" hereinafter) has a switch device for switching whether to bypass the expander in each communication path or not. Of the plurality of switch devices, an actual connection destination of a switch device bypassing the expander is a switch device in a upper-level and/or a lower-level of the switch device. Of the plurality of switch devices, an actual connection destination of a switch device that does not bypass an expander is the expander.</p>
