Solaris Multiplexed I/O (MPxIO), known also as Sun StorageTek Traffic Manager, is multipath I/O software for Solaris/illumos. It enables a storage device to be accessed through multiple host controller interfaces from a single operating system instance. The MPxIO architecture helps protect against I/O outages due to I/O controller failures. Should one I/O controller fail, MPxIO automatically switches to an alternate controller.