This counter tracks the cumulative megabytes read from this specific target port by all attached initiators. Paired with ciscoScsiTgtPortWrMegaBytes, an admin gets a read/write bandwidth breakdown per physical array port, useful for right-sizing port speed upgrades or confirming a specific port is not becoming the bottleneck for a read-heavy workload assigned to it. A port serving mostly analytics/reporting hosts might show read-megabyte growth well ahead of its write-megabyte growth compared to other ports on the same array.