# Erle Robotics Introduction to Networking in Linux

## IPv4 vs IPv6

As we have seen, at first glance, an IP address is like a phone number or a street address. When you connect to the Internet, your device (computer, cell phone, tablet) is assigned with an IP address, as well as each site you visit has an IP address.

The addressing system that we have used since the Internet was born is called IPv4, and the new addressing scheme is called IPv6.

It is important to define the difference between this two addressing systems.

To understand that the IPv4 address space is limited to 4.3 billion addresses, we can decompose an IPv4 address. An IPv4 address is a 32-bit number consisting of four octets (8-bit numbers) in a decimal notation, separated by periods. The bit can be either a 1 and a 0 (two possibilities), therefore the decimal notation would octet 2 raised to the 8th power of various options (256 of them, to be exact). Since we start counting from 0, the possible valuesof a byte in an IP address range from 0 to 255.

Examples of IPv4 addresses: 192.168.0.1, 66.228.118.51, 173.194.33.16

If an IPv4 address is made up of four sections with 256 possibilities in each section, to find the total number of IPv4 addresses, you should just multiply 256 256 256 * 256 to find results 4,294,967,296 addresses. To put it another way, we have 32 bits then 2 to the 32nd power will give the same result obtained.