Allied Telesis AT-S39 - Manual (Page 210)

Section II: Local and Telnet Management
210
CRC Error (CRC_ERROR)
Number of packets with a cyclic redundancy check (CRC) error but
with the proper length (64-1518 bytes) received on the port.
Undersize Packets (UNDERSIZE)
Number of packets that were less than the minimum length
specified by IEEE 802.3 (64 bytes including the CRC) received on
the port.
Oversize Packets (OVERSIZE)
Number of packets exceeding the maximum specified by IEEE
802.3 (1518 bytes including the CRC) received on the port.
Fragmented Packets (FRAGMENT)
Number of undersized packets, packets with alignment errors,
and packets with FCS errors (CRC errors) received on the port.
Port in Discards (PRT_DISCARD)
Number of frames successfully received and buffered by the port,
but discarded and not forwarded.
If you want to clear the counters on the port and return them to “0”,
select the option “3 - Clear Statistics” from the Ethernet Statistics menu.