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Understanding Internet Protocol (IP) Addresses

The Internet began its life as a Defense Advanced Research Project Agency (DARPA) initiative to create a global fault-tolerant communications network. This early project was called “ARPANET”. The designers of the network created a communication protocol for use on this network called “Internet Protocol” (IP). At the center of Internet Protocol are IP addresses. Much like a postal address an IP address defines the location of the device on the internet for data delivery.

Internet Protocol v4 addresses (IPv4) consist of a 32-bit binary address:

IP Address

Binary is difficult for most humans to read, so the binary representation is shortened into “octets” by converting the binary (base-2) digits to decimal (base-10).

The 32-bit address space provides for about 4.3 billion unique IP addresses. The original designers of ARPANET thought that would be plenty of addresses for a global network. Unfortunately they underestimated how popular commercial adoption of the internet would eventually become. The pool of public IP addresses became exhausted sometime around 2019. To deal with this problem, IPv6 was developed in the 90s and became an official standard in 2017.

Internet Protocol v6 addresses (IPv6) consist of a 128-bit binary address:

IP Address

IPv6 addresses are also in binary form and can be expressed in eight groups of hexadecimal (base-16) numbers separated by colons. These groups are called “quartets”. Quartets are much easier than binary for readability, but are a bit more difficult than 32-bit octets. Copy and paste is a useful tool when working with IPv6 addresses.

The designers of IPv6 wanted to avoid the address exhaustion problem of IPv4. The 128-bit IPv6 address space has 340,282,366,920,938,463,463,374,607,431,768,211,456 unique IP addresses. That’s enough for every square inch of planet earth to have its own unique IP address – with a huge amount left over!

IPv4 and IPv6 will co-exist on networks for the foreseeable future. If you use a modern smartphone, you use IPv6 every day. Current LTE/5G networks require IPv6 support as standard. Thanks to the designers of IPv6, no matter how many connected devices we desire, we will always have enough IP addresses to support them.


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