Waters Network Systems GSM2108 Operating Manual page 43

Rx Fragments:
Number of short frames (< 64 bytes) with invalid CRC.
Rx Jabber:
Number of long frames(according to max_length register) with invalid CRC.
Rx Drops:
Frames dropped due to the lack of receiving buffer.
Rx Errors:
Number of the error packets received.
Tx Collisions:
Number of collisions transmitting frames experienced.
Tx Drops:
Number of frames dropped due to excessive collision, late collision, or frame aging.
Tx FIFO Drops:
Number of frames dropped due to the lack of transmitting buffer.
Waters Network Systems User's Manual
GSM-2108/GSM-1008SFP
Page 43