IP related protocols

TCP UDP ICMP IGMP  
IP ARP RARP

IP protocol numbers

6TCP
17UDP

IP Header

Version (4 bit) Header length (4 bit) Type of service (8 bit) Total Length (16 bit)
Time to live (8 bit) flags (3 bit) Fragment offset (13 bit)
Source IP address (32 bit)
Destination IP address (32 bit)
[ Options (if any -- see header length) ]
Data (see total length for size)

UDP Header

Source port number (16 bit) Destination port number (16 bit)
UDP Length (16 bit) UDP checksum (16 bit)
Data (if any)

TCP Header

Source port number (16 bit) Destination port number (16 bit)
Sequence number (32 bit)
Acknowledgement number (32 bit)
Header length (4 bit) Reserver (6 bit) URG ACK PSH RST SYN FIN Window size (16 bit)
TCP checksum (16 bit) Urgent pointer (16 bit)
Options (if any)
Data