IPv4 and IPv6: the two main internet protocols compared

Computers and devices can communicate over the internet thanks to the Internet Protocol (IP). There are now two versions of IP, IPv4 and IPv6. Both are used to label devices connected to a network, but they differ in certain respects. In this article you will learn the differences between the two internet protocols, IPv4 and IPv6, in detail.

What is the Internet Protocol?

The Internet Protocol (IP) is a set of rules responsible for routing data across networks and delivering it to the right destination.

When data is sent over a network, the computer splits it into small units called packets, which makes the transfer faster and more efficient.

Every packet carries both the source and the destination IP address. An IP address is a unique identifier assigned to every device connected to the internet or a computer network.

Just as you need a mailing address to send a letter, a device needs the correct IP address to send information across a network.

IP addresses are allocated by the Internet Assigned Numbers Authority (IANA), a US-based organization that manages the pool of IP addresses.

Note that an IP address is different from a domain name, which is a website address that is easier to remember than a numeric IP address.

What is IPv4?

IPv4 is the most widely used protocol for moving data. It was designed as a connectionless protocol, meaning it sends packets without making sure the receiving device is ready. The advantage is that IPv4 can send packets along different paths if a router fails or a link in the middle has trouble.

IPv4 follows a best-effort model, so it does not fully guarantee quality or successful delivery. It is very flexible and can be configured automatically or manually on many kinds of devices, depending on the type of network.

This version of IP uses 32-bit addresses, the format most people picture when they talk about IP addresses. An IPv4 address consists of four decimal numbers between 0 and 255, separated by three dots.

A 32-bit address space provides about 4.3 billion addresses. However, a large share of them is reserved for private networks and is not available for public use.

What is IPv6?

Internet Protocol version 6 (IPv6) is the newer version of IP, also known as Internet Protocol Next Generation (IPng).

It works like IPv4 and gives every device connected to the internet a unique address. Unlike IPv4, though, IPv6 uses 128-bit addresses instead of 32-bit ones.

The 128-bit address space provides roughly 340 undecillion addresses, many trillions of times more than IPv4.

An IPv6 address is made of letters and numbers, written as eight groups of four hexadecimal digits separated by colons.

Besides offering far more addresses, IPv6 has a simpler header than IPv4. Its header uses a new format designed to cut header overhead, so packets are processed more efficiently.

IPv6 also makes services such as Voice over IP (VoIP) and Quality of Service (QoS) easier to implement and deploy.

Why are two IP versions needed?

The maximum number of IPv4 addresses looks huge, but it is not enough for every device connected around the world, especially with the growing number of devices Internet of Things (IoT).

That is why IPv6 was created: to meet the demand for more internet addresses. Even so, as the world moves toward the new protocol, IPv4 is still needed.

Many large content providers, such as Facebook and Netflix, can now be reached over IPv6. But only about 19.1% of Alexa's top ten million websites are reachable over it, which shows there is still a long way to go before IPv6 is fully adopted. For website hosting services, customers using Hosting VPS usually get IPv6 support too, which improves security and helps limit DDoS attacks.

IPv4 and IPv6: comparing the two network protocols of the Internet

Now that we know the features of IPv4 and IPv6, the differences between the two can be summarized in the table below:

Frequently asked questions

Have IPv4 addresses run out?

IPv4 addresses ran out around the 1990s. That is why the Internet Engineering Task Force proposed and began developing IPv6 in 1994.

Why not switch entirely to IPv6?

It can be done, but it will take a lot of time, probably decades. IPv4 is still very well optimized, and the cost of switching is high, among other factors, so a full move to IPv6 is unlikely within a few years.

What is ARP?

ARP (Address Resolution Protocol) is a protocol, or procedure, that links an Internet Protocol (IP) address, which can change, to a fixed physical machine address.

How can you protect your IP address?

You can protect your IP address in many ways. Among them, using VPN is the best-value and least costly option.

Mona hopes this article comparing IPv4 and IPv6 has helped you understand the differences between these internet protocols. If you have any questions, leave us a comment below.