The persistent binding of STP SAS addresses to SATA devices is disclosed so that SATA devices can be moved to different insertion points (ports) within a SAS expander and still properly receive I/O requests. When a SATA device is inserted into the SAS expander, it is interrogated to obtain information about the attached device. This information may be combined using a hashing function to obtain a unique ID for the SATA device. A table can be used to assign a STP SAS address to the Phy connected to the device based in the unique ID. In this manner, the same STP SAS address will be assigned to the Phy connected to a particular SATA device, regardless of where the device is connected to the SAS expander.