What does the message content in the ARINC 615A FIND protocol look like?
Attachment 3 of ARINC 615A-3 describes the FIND function. The FIND protocol has an Information Request (IRQ) packet and an Information Answer (IAN) packet. Each packet contains a 2 byte header and a variable length data portion.  


  3-4 Information Request Packet
  
  Source MAC address should be the MAC address of the data loader (or
  the initiator.  
  
  Destination MAC address should be a unicast, multicast, or the
  broadcast MAC address.  
  
  Source IP Address should be the IP address of the Data loader (or the
  initiator).  
  
  Destination IP address should be a unicast, multicast, or a broadcast
  IP address (full broadcast i.e., 255.255.255.255 or class-relevant
  broadcast e.g., 220.130.48.255 for a class C).
  
  Opcode value should be IRQ (0x0001).
  
  Data list should be a null ASCII string with terminator: 0x00.  
  
  Packet is terminated by 0x10.