Internet Protocol

For information about Internet Protocol (IP) headers, see the following table.

For the IP specification, see RFC791 available at http://⁠www.rfc-editor.org.

Table 1. IP datagram
bits 0–7 bits 8–15 bits 16–23 bits 24–31

Version

(4 bits)

IP Header Length

(4 bits)

Type of Service

(8 bits)

Total Length

(in number of bytes) (16 bits)

IP Identification Number

(16 bits)

Flags

(3 bits)

Fragment Offset

(13 bits)

Time to Live

(8 bits)

Protocol Number

(8 bits)

Header Checksum

(16 bits)

Source IP Address

(32 bits)

Destination IP Address

(32 bits)

Options (if any)

+

Padding (matching to 32-bit boundary)

( data . . . )