Bits 12 16 20 24 28 Padding 31 0 4 8 Source Port Sequence Number Acknowledgement Number
URG ACK PSH RST SYN

1 2 Words 3 header 4 length 5

Destination Port

Reserved Checksum

FIN

Window Urgent Pointer

Options (0 to 40 bytes) 5−15 Your data starts here