For example:

# linkloop -i 4 0x1CC1DE316BF0
error:  expected primitive 0x04, got DL_ERROR_ACK
   dl_error_primitive = 0x01
   dl_errno = 0x04
   dl_unix_errno = 16
Link connectivity to LAN station: 0x1CC1DE316BF0
error:  expected primitive 0x30, got DL_ERROR_ACK
   dl_error_primitive = 0x2d
   dl_errno = 0x03
   dl_unix_errno = 0
error - did not receive data part of message
  1. The device you are trying to connect to is not on same subnet.
  2. The switch or another network device blocks linkloop packets at hardware level. linkloop sends a “special” (but standard) 802.3 frame type. (XID or perhaps TEST). The IEEE specs say such a frame should elicit a response, but precious few implementations outside of HP (UX, perhaps iX) seem to do it.
  3. The device you are trying to connect to is bad (faulty NIC).