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People get caught up in how many IPv6 addresses exist, as if we will always have enough to go around. Recently Capital One was assigned a /16, enough for every ATM in the US to be its own ISP and make its own customer allocations. We continue to repeat the same mistakes that made people believe we needed v6 in the first place.

We will never run out of IPv6, but I believe in my lifetime you won't be able to get new v6 allocations anymore because they will have all been handed out to the large corporations with deep pockets. Oops, no addresses left - but you can rent one from a cloud provider for a few dollars a month.

Then, we’ll make IPv8, with 2^1024 address, which will be incompatible with IPv6 and IPv4 and all software on release, and will take decades before any appreciable uptake. Addresses will use hexadecimal, as well as the entire 4-byte Unicode table of emoji and Egyptian hieroglyphics, with octet separated by $ and { symbols for heightened readability.

No, we won't do that.

I believe IPv8 does something else:

https://py-ipv8.readthedocs.io/en/latest/

IPv8 dev here. Thnx for mentioning this.

IETF draft standard of IPv8: https://datatracker.ietf.org/doc/html/draft-pouwelse-trustch...

Bonus: "De-DSI" == LLM- based fuzzy search + IPv8

The time the think of deploying IPv8 is BEFORE you've deployed something else.

https://www.youtube.com/watch?v=qYo0lVVH2wU

Yet there will still be comments asking why IPv8 can't be IPv4 with another few sets of digits tagged onto the end, as if that would somehow be compatible with the current implementation of IPv4.

I swear it is easier to argue with flat earthers than with people who want IPv4 but with more addresses.

I just hope that by making the joke, I won't accidentally make fetch happen :-D

A /16 is the first quarter of the network prefix. That is indeed like assigning an IPv4 /8 to General Electric in 1985 and then wondering why, 40 years later, we’re out of address space.

You’re leaning heavily on “like” here. The address spaces are different. That’s the point.

Except, we're not actually "out" out. There is a very active IPv4 transfer / resale market. There is a LOT of unused or underused address space out there. I know one local firm with a completely unused /16 that they have not announced in years.

> Recently Capital One was assigned a /16

So besides the bad design ipv6 is also badly managed?

Wait until you see IPv4

So why does 6 have to repeat 4's historical (and very publically recorded) mistakes?

People thought there was not enough bureaucracy and wonder why it's not improving after adding bureaucracy.

No, it's ARIN that's badly managed.

Capital One would never get a /16 in RIPE.

Thanks, I missed this story. According to https://old.reddit.com/r/ipv6/comments/17yuqvp/til_capital_o..., the largest allocations by RIRs other than ARIN do not exceed /19, and those are for national telecom providers. Who are these ARIN people and how can they be held accountable for their idiotic management of public resources, which appear to be consistently terrible for decades?

> We continue to repeat the same mistakes that made people believe we needed v6 in the first place.

The IPv6 designers already thought of that and prepared for that eventuality. Only 1/8 of all available IPv6 addresses (the ones starting with the bits 001) is available for allocation under the current rules. If and when that gets exhausted, there will still be more than 5/8 of all IPv6 addresses available to be allocated under more strict rules. (See https://www.iana.org/assignments/ipv6-address-space/ipv6-add... and https://www.rfc-editor.org/rfc/rfc3513.html#section-4 for more details.)

Do current routers deal with other addresses correctly? This reminds me a little of the challenges in reclaiming 240.0.0.0/4 [0].

[0] - https://blog.benjojo.co.uk/post/class-e-addresses-in-the-rea...

> Only 1/8 of all available IPv6 addresses (the ones starting with the bits 001) is available for allocation under the current rules.

Yes yes yes, all sorts of really super serious policies were put in place to prevent abuse of IPv4 allocation rules too.

The IPv6 address space is so huge, I, as an individual, was able to get a /44 no questions asked. Back in the 90's, I was able to get a IPv4 /24, no questions asked.

There are only ~16.7 million /24s in IPv4 whereas there are more than 2000 /44 for every person living on planet earth, it’s really a different scale.

/44 is nothing. It’s 16 /48s.

I have a /32 as an individual that I also got no questions asked.

It’s more IPv6 space than I could ever use.

I understand it's "nothing", but it's also more I can ever use!

If we measure it in /64s, yeah, it's definitely more than you could ever use.

However, IPv6 space has to be measured in /48s, and IPv4 in /24s, as those are the smallest possible BGP announcable blocks.

With IPv6 there's also an unwritten rule that RIRs will only assign blocks ending on a nibble boundary (with the exception of RIPE and their /29s that they expand by one bit every time you run out).

So a /44 is on the second smallest nibble boundary, making it the second smallest allocation possible.

Yep! But realistically I'm just one dude with a home network and a few VPSes doing BGP. How many /48s do I need? I was experimenting with traffic engineering so I did announce some /48's out of the /44 but that got old pretty quick.

> But realistically I'm just one dude with a home network and a few VPSes doing BGP. How many /48s do I need?

Well, if the VPSes are in seperate sites, at least one per VPS, which means at least 2, which means that according to allocation policies, at least a /44. :)

It’s really hard to even comprehend how large IPv6 is. I have found that extreme examples tend to help people get there. Here are some I’ve used in the past.

There are enough IPv6 Addresses for 4.77 x 10^28 for every living person.

If each IPv6 address was a grain of sand…

That’s 2.39 × 10^18 of addresses per person, or roughly enough sand sized addresses to equal about 1.8 times the volume of earths ocean per person.

At sand scale all IPv6 addresses would take the volume of 12 sols.

Conversely, all the IPv4 addresses in this sand scale would slightly over fill an oil drum.

From “IPv6 Addresses: Big Numbers, Big Solutions”: https://www.osti.gov/servlets/purl/1365362

Hah - all of those examples use a planet as comparison. The first 16 bits of the address should be reserved to be used by the Planetary Internet Addressing Council (PIAC)

Allocating all addresses to Earth seems very shortsighted.

(Some sarcasm should be assumed.)

It doesn't really matter how you explain large-number math to people who are bad at large-number math (aka all of us) - there's always some bright-spark who misses the point.

The moon can share with the earth, and anything further away needs special encapsulation to deal with hours or more of latency.

It's only minutes for the inner planets. But of course that's already enough to require special treatment.

Well we could argue that this support for trillions of IP addresses is nice, except that IPv6 does not technically work in interplanetary environments due to various hardcoded timeouts.

The first martians are likely to run their own local network and then use a VPN over DTN for their everyday communications by email (and appear coming from a single IPv6 address).

One good thing though: since most of the humanity’s knowledge is going to be packed in an LLM they won’t really actually need internet to learn about things. But lack of videos may be annoying.

I see only one IPv6 timeout, for fragmented packet reassembly, in other words between reception of fragments. So it's a bound on jitter not latency, and I see no reason it couldn't be increased for interplanetary links.

I think it's more useful to comprehend it as 64+64 though.

We can give every person a million local networks, with unlimited devices on each local network. That's more accurate and also easy to think about.

In current practice it's more like a global 61+64. We're all inside the globally routable /3 with ULAs on the side.

Chess has 1e100 possible games but the more practical metric is that the average game involves 40 black moves and 40 white moves.

Similarly, it’s better to think of the depth of a network’s topology. The size of the tree when full is immaterial, especially when the last 64 bits is intended to be so sparse that random address assignment is viable.

I missed the edit deadline and wanted to add:

So instead of talking about there being 2^128 addresses, it’s more useful to talk about there being 4k global regions (/12 RIRs), assigning /32s to ISPs in their region.

Each ISP can assign a /48 to each customer site, which can then subdivide into 256 buildings with 256 VLANs each (or some other balance of the these, eg 8 buildings with 64 floors each and 128 VLANs on each floor) with the hosts selecting randomly (or SLAACly) from the final 64 bits.

Some ISPs where customers are in a single dwelling will only give you a /56.

> It’s really hard to even comprehend how large IPv6 is.

But the allocations for a single device are so large that it's not actually as large as it seems to be. Kinda like usb N only working at N-2 speeds...

One problem of ipv6 is proponents saying there are 2^128 addresses.

It's really hard to comprehend how many unusable ipv6 addresses are.

Having more than 2^16 hosts on a subnet is pretty much impossible. Sticking with "grain of sand" units, but using volumes all from wolfram alpha:

There's 2^80 usable IPs in the entire ipvv6 space, because of the /64 subnets. That's plenty. But for every subnet, that's 40 cubic metres unusable for every subnet, and a sphere 1mm wide of usable addresses.

My ISP give me a /48. I have under 30 addressable devices over 3 vlans. I'm using 40 cubic miles of space. A ratio of about 10 trillion:1

But that's nothing. The IP allocators are happy to give a bank a /16, or in your "grain of sand" measurements 30 times the volume of the moon.

To match my unused:used ratio of 10 trillion to one, chase manhattan would need 2^70 devices, which is billions of addresses per cell.

All the space that fanboys go on about is almost all unusable, so the extreme examples don't really help at all.

The thing is, there are just as many /28 IPv6 ranges as /28 IPv4 ranges. And the experience with IPv4 is that it's those larger ranges that we've run out of the quickest. The whole power of IPv6 is that assigning a huge global business a /32 gives them enough addresses to run more devices that exist on the whole Internet today. But if we're distributing large swaths of IPv6, we'll run out just the same, unless we try to later claw them back like we did with some IPv4 /8 spaces.

Now, of course, a /28 in IPv4 is a tiny range, while a /28 in IPv6 is huge. And there are, of course, a lot of /28s. The fear is only that we may start seeing larger and larger allocations for no good reason whatsoever. Apparently already some random private company (Capital One) has received a /16 IPv6 range - this is an absurd allocation that should simply not be allowed if we don't want to have to move to a new IP version in a few decades.

> does not accurately describe how large the ipv6

It is not the limitation, but router hardware is.

Now problem mostly eased, thanks to Moore law, but 20 years ago router memory need to store prefixes-routes graph was very expensive and have some problems with grow.

For example, I know people, bought very expensive server PC boards (but cheap compared to enterprise networking hardware), with DDR2 capability, because it was fastest at that time and promises large RAM space.

Imagine their frustration, when they seen, this hardware cannot allocate prefixes list for their installation (just not enough RAM) and they have to buy new hardware with DDR3.

This even caused "curse of /24", when some providers decided to just discard /24 prefixes and work only with /16 directly and for smaller allocations use some default route.

And this is just because nature of Internet, which is by definition "network of networks", mean, in ideal case all networks should have peer connections at least to all first circle neighbor networks, but better if have peers to few first circles, plus connections to large local hubs.

And now problem become harder, because of grow of p2p solutions, which by definition avoid hub model and use all peers directly.

BTW, colleague from telecom share latest problem - few days ago appear huge traffic. In very short time found source - after appear new "Stalker" game, their developers made huge number of fixes, so fixes are larger than installation, and they somewhere bought so powerful distribution network, distribution of fixes flooded all connections for few days.

There are attempts to address that like LISP https://www.rfc-editor.org/rfc/rfc9300.html

> I feel like this blog does not accurately describe how large the ipv6 address space even after accounting for it being reduced by 2^64 for the host portion of the address.

One way of thinking about it:

* Stars in the Milky Way: 400 Billion

* Galaxes in the universe: 2 Trillion

So (4x10^11)x(2x10^12)=8x10^23 stars in the universe.

* Size of IPv6 address space: 3.4x10^38

Find the ratio between addresses and stars:

* 3.4x10^38 / 8x10^23

IPv6 offers about 430 trillion times more addresses than estimated stars in the universe. From Tom Coffee's presentation "An Enterprise IPv6 Address Planning Case-Study"

* https://www.youtube.com/watch?v=7Tnh4upTOC4

Perhaps in more human terms: on the surface of the Earth (including oceans), there are 8.4 IPv4 addresses per km^2. Not counting the oceans, that would be 28 IPv4 addresses per km^2 land.

IPv6 gives 10^17 addresses per mm^2 (yes, square millimeter).

In terms of volume, 10^8 IPv6 addresses per mm^3 throughout the Earth.

Another way of looking at it:

*math property: x^y = x^(a+b) = (x^a)x(x^b)

* IPv4 addresses are 32 bits (2^32)

* 2^32 ~ 4.3 billion

* So the IPv4 Internet has ~4.3B devices on it

* IPv6 subnets are 64 bits, /64 (2^64)

So, an IPv6 2^64 subnet is the same as (2^32)x(2^32), which means (4.3B)x(IPv4 Internet). I.e., a single IPv6 subnet can hold the equivalent of four billion (IPv4) Internets.

Except that IPv6 is actually not that large. You effectively can't use networks that are smaller than /64, because stateless autoconfiguration can't use any other prefix size (there's an effort to fix it, but it'll take a decade at best)

You can absolutely use them, you just need static or DHCP addressing just like the old days. But thanks SLAAC for forcing my ISP to give me /64 or bigger so I can always subnet into /96 for example.

How many devices actually support DHCPv6? SLAAC is pretty much the standard way of assigning addresses these days.

Just about anything with a screen these days. The biggest holdout is Android and a bunch of IoT stuff.

SLAAC works on any device that supports DHCPv6, though, so you might as well use it if you don't have any requirements to favour DHCPv6

That was my whole point. There are not 2^128 ipv6 addresses for Individual use but there are 2^64 /64 networks.

If you rent a vps with a ipv6 “address” you will see that you are given a /64 network.

There is no effort to “fix” the bottom 64 bits because it’s not needed. There are enough /56 networks to for the next 500 years and 99% of people can do everything they need with an isp provided /56. IPv4 has survived with 48 bit nat for this long so 64 bit is even more buffer space

> If you rent a vps with a ipv6 “address” you will see that you are given a /64 network.

Unfortunately, I've seen multiple VPS providers that will assign you a single address within a /120 or something ridiculous like that.

I presume whoever runs the network side of things with those VPS providers has never used IPv6 themselves or they must be _extremely_ stingy.

Meanwhile my home ISP (Charter) will gladly give me a /60 if I set my router to ask for one.