8 bytes preamble

6 bytes dest addr MAC

6 bytes src addr MAC

2 bytes frame type

½ byte version

½ byte hlen

1 byte service type

2 bytes total length

2 bytes id

½ byte flags

1 ½ byte fragment offset

1 byte time to live

1 byte protocol

2 byte header checksum

4 bytes src addr IP

4 bytes dest addr IP

2 bytes src port

2 bytes dest port

2 UDP message length

2 bytes UDP checksum

'h'

'i'

32 bytes of padding

4 bytes Ethernet CRC checksum