Week 6

The instructions for the blog post say not to just copy discussion posts over, but we’ve only talked about one thing this week: IPv6 addresses, and the incredibly large number of addresses created with 2^128 bits is very fascinating to me so I’m doing it anyway! (Though with a few different examples than the discussion post).

IPv4 addresses use 2^32 bits to store the information which gives you a little over 4 billion addresses. Since a billion in and of itself can be quite difficult to comprehend, let’s talk about a billion dollars for a second. If you made $100 a minute ($6000/hr) every day of your life, that would equate to $144,000 a day. Even with 4x my annual salary in a single day, it would take you 19 years to get up to just one billion dollars. Expanding on that, we can determine that it would take you 81.7 years to reach the amount of IPv4 addresses we have available. (On a side note, how much is Elon musk making to be evaluated at almost 400 billion dollars? With your *pathetic* salary of $6000/hr, it would take you 7,496 years to reach his net worth...)

With that being said, somehow, we’re starting to run out of IPv4 addresses and IPv6 was created to solve that problem, and they managed to do it in probably one of the most overkill ways possible. They took the 32 bits in the IPv4 address space and added an additional 96 bits on top of it, making the new address space 128 bits total which equates to an impressive 340 Undecillion addresses which is, if you couldn’t guess, an insanely large number. To hopefully put that in perspective, let’s assume Elon started building his wealth in the year 2000, and has since gotten it up to his 400-billion-dollar mark in the last 25 years. That’s 16B/year, 43.8M/day 1.8M/hr. But we’ll be nice and call it 2 million an hour for our math. If you made 2 million dollars an hour, you would need to collect that money for 21 octillion years. What does that mean? The universe is estimated to only be around 14 billion years old. If you watched the universe from its start to right now 1.5 quintillion times over on repeat, you’d be close. But 1.5 quintillion times is still an astronomically huge term that even that is hard to find perspective on.

Let’s try something else. Light can travel approximately 300 million meters per second. This ratio stays the same no matter what prefix you use in front of the numbers, for example, light will travel 300 million millimeters per millisecond, or 300 million micrometers per microsecond, etc. Using this, we can say that light will travel 300 million yoctometers in a yoctosecond. Converting to numbers that make a little more sense, that is 0.3 femtometers (one femtometer is one millionth of a nanometer) in 1 septillionth of a second. To put it into a little more perspective, Visible light starts to be detected by the human eye when light reaches around 400 nanometers or so. To get to one nanometer, light takes 3.3 million yoctoseconds. 1.3 billion yoctoseconds later, light will have travelled the distance of the wavelength necessary for you to start detecting it.

With that being said: If you assign one IPv6 address every yoctosecond (I.E. Assigning 1,000,000,000,000,000,000,000,000 addresses per second) by the time you reach the infra-red spectrum (about 1200 nm) which is what single mode fiber optic cables use for transmission, you will have already passed the entirety of the 4 billion IPv4 addresses. Once light has travelled the width of a human hair (0.1mm) you will have assigned 333.3 billion addresses. By the time light has had a chance to span the width of a pencil lead (~1mm), you will have assigned 3 trillion addresses. By the time it spans the width of a quarter (~2.5cm) we’ll be at 83 trillion. By the time it reaches the height of a smartphone (~10cm) it will be about 333 trillion. By the time we reach the length of a football field, we will have passed 333 quadrillion. Once it passes the diameter of earth we will have assigned 42 sextillion addresses. At the moon we will have reached 1 septillion. To the sun we’ve only got to 500 septillion with a LONG way to go. Fast forward a little bit, to one light year away (about 9.4 trillion kilometers) we will have assigned 31 nonillion addresses. We’re still not even close. Fast forwarding quite a bit at this point, the closest observable galaxy is the andromeda galaxy at around 2.5 million light-years away. Once our light source makes it there, we will be a little under one quarter of the way through our IPv6 address space. If we go back to earth, return to Andromeda for a second time, back to earth a second time, and head back towards Andromeda, about 36% of the way there, we will finally run out of addresses.

TL;DR If you spent the next 10.5 MILLION years assigning 1 septillion (1,000,000,000,000,000,000,000,000) address EVERY SECOND, you would still have to spend an additional 280 thousand some years to run us out of addresses. I think we should be good for a while.