This is the current traffic throughput on this FDDI connection, measured in frames per second rather than raw bytes. It lets an admin distinguish a high-frame-count, small-packet load from a high-byte-count, large-packet load, since the two stress different device resources. For example, a frames-per-second count that's disproportionately high relative to bytes per second suggests a flood of small frames, such as excessive broadcast traffic, rather than a bulk file transfer.