

The Sheer Size of IPV6 - timf
http://pthree.org/2009/03/08/the-sheer-size-of-ipv6/

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tptacek
Well this post sure makes an incisive point about the power of... successive
powers of 2? We could add just 4 bits to IPv4 addresses and address any
reasonable addressing argument, providing 10-20 static IP addresses for every
man, woman, and child on the planet. That's not the challenge.

The challenges are:

* It is extremely painful to migrate from IPv4 to IPv6, not just because of the obvious stuff (like renumbering and upgrading routers) but also because tons of important programs are written to assume an IP address is 4 bytes long, or fits in a scalar data type.

* The argument for enduring that pain is weak. There are 6 billion people in the world, so we can't number them directly. But I haven't had a static IP address in years and years, and if you offered me an address out of 172/8 for my laptop I wouldn't take it. Most of the Internet works fine through NAT, and the trend is towards more NAT-friendliness.

* Any argument about the scarcity of IP addresses is clouded by the fact that IP addresses are doled out OPEC-style by a cartel of standards groups with an ideological bias towards hastening IPv6 adoption. There's no liquid market for netblocks, so we don't know what they're actually worth. Of course, if we had such a market, we'd probably find out that they're not worth all that much to people with laptops, and readily affordable for people with servers.

Put differently, in a vain attempt to steer this back to the topic at hand:
you could make a similar point about the sheer size and flexibility of ASN.1
and X.500 directory naming schemes. But nobody's talking about chucking the
DNS to get that.

~~~
trezor
While I'm not going to dismiss your argument entirely, it basically boils down
to "Migrating to IPv6 is hard. Let's go shopping". Now the question which
would be reasonable to ask is _how_ hard would this migration actually be,
coupled with how needed it actually is.

Right now you might say "There are 6 billion people in the world. Exploiting
the existing address-space more efficiently, coupled with NAT will be 'good
enough'". This may or may not be true as for now.

However, fast forward one generation, 30 years, whatever. Lets
(optimistically? pessimistically?) assume world population is doubled. How
about now? Will squeezing the existing address-space coupled with NAT be
enough?

At this point there will be 3 people per IP address. And most people will
probably have more networked devices than ever, accustomed to being able to
work with data independent of network location.

Sure we can add hacks on hacks to make this viable, but at some point we will
have to toss IPv4 out and accept that there will be a painful migration. At
some point these hacks will cause more pain than a migration away from IPv4.

The question is not as much _if_ we will have to ditch IPv4 but when. If your
argument is that we have too much stuff which relies on current IPv4
configuration now, imagine in 30 years.

In short: Your primary concern is not going to get any better.

~~~
tptacek
First: "IPv6 is hard, let's go shopping" is exactly what happened on the
Internet. Several hundred billion dollars later, nobody much cares about IPv6.

Second, when you make an point like "NAT may or may not be good enough", the
onus is on you to support that point with evidence. Most of the problems NAT-
unfriendly technologies were supposed to solve have instead been solved by
brute force; HD movies move just fine over inefficient HTTP CDNs.

The rest of your comment just ignores my argument, which is that individuals
don't need routable IP addresses for the Internet to work. Many of us never
even use routable IP addresses. 6 billion, 10 billion, 20 billions --- as long
as the next YouTube can get reachable servers online, what do I care whether
my iPencil has a 1918 address?

Networking technologies are "hacks" when they challenge the greybeard
orthodoxy, and they're "sound engineering" when they don't. It's funny how
quickly we forgot that the Internet itself was a pragmatic reaction to OSI
standards. You want to see a "hack"? How about, the NSF decides that
commercial entities shouldn't connect to the NSF backbone, and the entire
Internet splits in two, and I can't get to University sites from Ripco in
Chicago? Guess how long ago that happened? Sorry if I can't get all worked up
over whether my phone can talk to your phone over direct BitTorrent.

~~~
Andys
I feel like we could have just added another byte to IPv4.

It would have been a very simple hack, which makes it more likely to succeed.
Also I love the way I can remember IP addresses off by heart right now - that
is almost impossible with ipv6.

~~~
wmf
The cost of migrating from IPv4 to IPvAndys is more or less equally huge as
the cost of migrating from IPv4 to IPv6. If you're going to pay a huge
migration cost, you might as well do a thorough job of it.

~~~
derefr
There is a really easy way to do it _right now_ , that just involves recoding
some drivers (no hardware needs to be changed): steal the port bytes from TCP
and UDP and use them as two additional bytes of host address. No server is
using all of its ports; turning them into addresses (and requiring a server to
have as many addresses as it has connections open) would flatten the two
spaces together, which seems almost elegant to me.

~~~
tptacek
You realize that if you did this, your computer could only ever open 256
concurrent outbound connections to a single host, right?

If you really were going to upgrade every router and switch on the Internet
and port every single program that used the BSD sockets interface or the Win32
WSA Socket interface, and for some perverse reason you felt you needed a
backwards-compatible frame format, you wouldn't break TCP or UDP to do it.
You'd add a pair of IP options, called "source address extension" and
"destination address extension".

But of course, you wouldn't do this, because if you're going to go through
that much pain, you might as well get the full IPv6 address space.

~~~
Andys
I'm just not sure thats the case. IPv6 has too much of a 'design by committee'
feel to it, which usually means it falls over as a standard in Internet land.

~~~
tptacek
What feels "design-by-committee" about IPv6 to you?

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sam_in_nyc
I think it's pretty amazing that you'd have to have a 52ft x 52ft monitor to
display all of the addresses in IPv4... and that 88% of the pixels on the
screen would represent a device hooked up to the internet, _right now_.

~~~
wmf
That's an oversimplification, since not all assigned addresses are used.

~~~
sam_in_nyc
I guess I'll just have to wait another year to be amazed. :(

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jodrellblank
With 128bit addresses, it makes it the same size as the GUID address space,
and betterexplained.com has this to say:

[http://betterexplained.com/articles/the-quick-guide-to-
guids...](http://betterexplained.com/articles/the-quick-guide-to-guids/)

"Think about how big the Internet is: Google has billions of web pages in its
index. Let’s call it a trillion (10^12) for kicks. Think about every wikipedia
article, every news item on CNN, every product in Amazon, every blog post from
any author. We can assign a GUID for each of these documents.

Now let’s say everyone on Earth gets their own copy of the internet, to keep
track of their stuff. Even crazier, let’s say each person gets their own copy
of the internet every second. How long can we go on?

Over a billion years.

Let me say that again. Each person gets a personal copy of the internet, every
second, for a billion years."

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klahnako
Should have compared cubes instead of squares

