Use the nicinfo command:
/usr/sbin/nicinfo device
This utility displays information about the given network interface connection, or all interfaces if you don't specify one. The information includes the number of packets transmitted and received, collisions, and other errors, as follows:
3COM (90xC) 10BASE-T/100BASE-TX Ethernet Controller Physical Node ID ................. 000103 E8433F Current Physical Node ID ......... 000103 E8433F Media Rate ....................... 10.00 Mb/s half-duplex UTP MTU .............................. 1514 Lan .............................. 0 I/O Port Range ................... 0xA800 -> 0xA87F Hardware Interrupt ............... 0x7 Promiscuous ...................... Disabled Multicast ........................ Enabled Total Packets Txd OK ............. 1585370 Total Packets Txd Bad ............ 9 Total Packets Rxd OK ............. 11492102 Total Rx Errors .................. 0 Total Bytes Txd .................. 102023380 Total Bytes Rxd .................. 2252658488 Tx Collision Errors .............. 39598 Tx Collisions Errors (aborted) ... 0 Carrier Sense Lost on Tx ......... 0 FIFO Underruns During Tx ......... 0 Tx deferred ...................... 99673 Out of Window Collisions ......... 0 FIFO Overruns During Rx .......... 0 Alignment errors ................. 0 CRC errors ....................... 0.