Abstract: For a storage area network, verification of path selection protocol comprises disabling a switch port on a switch of the primary path of a data storage device; initiating an input/output command to the device; verifying that a failover occurred. The switch port for the primary path is enabled, an “immediate” input/output command is initiated to the device with the “immediate” bit set; and, in response to a notification by the device resulting from the “immediate” bit, a switch port is disabled on the switch of the primary path for the device; and the method verifies that a failover occurred.