This read-only PerfCounter64 counts frames of 512 to 1023 octets received on this link aggregation group as retained in the history bin. It adds another bucket to the historical frame-size profile an administrator uses to understand typical payload sizes traversing the bonded link. For example, a steady baseline of cmLagHistoryESP512 alongside a sudden rise in the 1024-1518 bucket could indicate a new bulk file-transfer service beginning to use slightly larger frames on this LAG.