Packet Layout

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Header:

  • Bytes 0, most 4 significant bits: Packet Information
    • LL_ACK_FLAG 0x10
    • LL_RESENT_FLAG 0x20
    • LL_RELIABLE_FLAG 0x40
    • LL_ZERO_CODE_FLAG 0x80
  • Bytes 0, (4 least significant bits) to byte 3: Packet ID, assigned by circuit
  • Everything beyond this is zerocoded for compression
  • Bytes n thru n+(frequency size)
    • 1/2/4 byte ID of the message the packet contains
  • Bytes n thru n+(data length)
    • Body of packet, possibly zero coded.
  • Bytes n+(data length) thru acks
    • Rest of packet is fill with as many acks as will fit from reliable messages