This counter tracks the cumulative amount of data, in megabytes, that this initiator port has received (read) from the fabric. Paired with ciscoScsiIntrPrtWrMegaBytes, an admin gets a read/write bandwidth split for each host port, useful for distinguishing read-heavy workloads (like a reporting server pulling large datasets) from write-heavy ones. A data-warehouse host's initiator port showing read megabytes far exceeding write megabytes would be the expected pattern for that kind of analytical workload.