Vint Cerf Keeps Blaming Himself For IPv4 Limit

netbuzz writes "Everyone knows that IPv4 addresses are nearly gone and the ongoing move to IPv6 is inevitable if not exactly welcomed by all. If you've ever wondered why the IT world finds itself in this situation, Vint Cerf, known far and wide as one of the fathers of the Internet, wants you to know that it's OK to blame him. He certainly does so himself. In fact, he does so time and time and time again."

Comments

Things people do...

[Anonymatt]

Is this a backwards opportunity taken for asserting that he is one of the Fathers of the Internet?

Re:Things people do...

[Hognoxious]

We all know it wasn't him. Seriously - is there anyone here who doesn't know who algoreithms are named after?

Glad thats sorted out!

[powerlord]

Cool. Now that we've assigned blame, hopefully we can move forward with FIXING the problem.

Since there is already a fix available (IPv6), if/when this DOES become a problem, THAT problem should be assigned squarely on the shoulders of the people who failed to implement the FIX in a timely enough manner.

Re:Glad thats sorted out!

[hardburn]

Except IPv6 is hierarchical, for that very reason. Routing tables can be much, much smaller than they are on IPv4.

Don't blame him, thank him.

[Matt Perry]

It's a good thing IPv4's address space is 32-bit. Without that limitation we'd never move to IPv6 and get all of the other benefits that it offers.

Re:Don't blame him, thank him.

[Yvan256]

We should have put Gillette in charge of the solution. I'm pretty sure it would have been "fuck everything, we're doing 256-bit". IPv6 won't last long once we start assigning an IP address to everything* such as light bulbs, toasters, etc.

* no, we won't stop to think if we should. We'll only see that we can.

Re:Don't blame him, thank him.

[abigor]

Eh, that's a lot of toasters to use up 3.4*10^38 addresses. If a toaster takes up a square metre (big toaster), you'd have to stack them ten billion high over every single metre of the Earth to use them up.

Is it a software patents issue? (alan cox)

[ciaran_o_riordan]

In a speech around 2004, I remember Alan Cox said that the reason IPv6 wasn't advancing was that big software players were afraid to adopt it before it turns 20 in case there are submarine patents / patent ambush.

Anyone got links to confirm / disprove this theory?

http://en.swpat.org/wiki/Patent_ambush

an alan cox interview

[ciaran_o_riordan]

Here's an interview where he says it:

http://www.velocityreviews.com/forums/t576610-alan-cox-on-software-patents.html

"""Alan Cox: The same has happened with IP version 6. You notice that everyone
is saying IP version 6 is this, is that, and there's all this research
software up there. No one at Cisco is releasing big IPv6 routers.
Not because there's no market demand, but because they want 20
years to have elapsed from the publication of the standard before
the product comes out -- because they know that there will be
hundreds of people who've had guesses at where the standard
would go and filed patents around it. And it's easier to let things
lapse for 20 years than fight the system."""

(More info would be good - any other prominent techs saying this?)

Re:Bogus shortage

[jandrese]

The scary thing is that for every Class A returned to the pool, you only buy like a month of life for IPv4. It's just growing too fast now and we're going to start seeing a lot of stories about people not getting their IP addresses in a year or two. Luckily it won't affect existing customers too badly, but it will be a real limit on growth.

How we got here.

[Animats]

At the time, XNS, the Xerox protocol for Ethernet networks, was in use. It had 24 bits for the network number, and 24 bits for the device ID. Thinking at the time was that each network would be a local LAN, and "internetworking" would interconnect LANs. Xerox was thinking of this as a business system, with multiple machines on each LAN. So XNS had a 48-bit address spade. That's what we call a "MAC address" today.

The telephony people were pushing X.25 and TP4, which used phone numbers for addressing. Back then, phone numbers were very hierarchical; the area code and exchange parts of the number determined the routing to the final switch. "Number portability", where all the players have huge tables, was a long way off.

The problem with a big address space is that memory was too expensive in those days to deal with huge address tables. A big issue was locative vs non-locative address spaces. In a locative address space, there's a hierarchy - you can take some part of the address and make a local decision about what direction to go, even if you don't have enough detailed information to get to the final destination. IP was originally organized like that - routers looked up class A, B, and C networks. A huge, flat address space implemented using multi-level caches was way beyond what you could do in a router back then. Routers used to be dinky machines, with less than one MIPS and maybe 256K of RAM.

There was a lot of worry about packet overhead. Each key press on a terminal sends 41 bytes over a TCP/IP network. That was a big deal when companies had long-haul links in the 9600 to 56Kb/s range. Adding another 24 bytes to each packet to allow for future expansion seemed grossly excessive. Especially since the X.25 people had far less overhead.

So there were good reasons not to overdesign the system. I don't blame Cerf for that.

The foot-dragging on IPv6 is excessive. The big deployment problem was getting it into everyone's Windows desktop. That's been done.

IPV6 is the problem.

[Anonymous Coward]

Choosing 32 bits for IPV4 was reasonable at the time when 56kbps was considered a fast link.
The real problem is that when IPV6 was designed it did not allow IPV4 to be included as a subspace.
so you cannot have an IPV4 address that is a valid IPV6 address.
That means that there is no soft migration path from IPV4 to IPV6.
The people who designed IPV6 did not consider the problems of real world users;
they designed in a vacuum. A properly designed IPV6 would be in widespread use by
now, and the problem would be under control.

Re:IPV6 is the problem.

[Anonymous Coward]

IPv4 was created decades before 56kbps was considered a fast link.

I've heard this complaint before about IPv6 not being backwards compatible, but, and no offence, I've never heard a constructive argument about how it should have been designed. I have my doubts that people who make this complaint have actually sat down and worked through the details of how they would have made IPv6 backwards compatible.

Consider a hypothetical IPvA (short for IPvAwesome) which obsolesces IPv4 and is backwards compatible. We have to imagine that the IPvA address space is bigger than 32 bits, either a fixed larger address space or a variable-length "extension" address stuck in the optional parts of the IP header or something like that. The problem is that no matter what mechanism you choose, every packet you send across the Internet is going to hit a 10 year-old router that's never even heard of IPvA. There's a 100% chance this router will have no idea whatsoever what to do with the parts of the IP header it's never seen before. If you're lucky the router will just drop the packet as being malformed. If you're unlucky maybe it'll do something silly like truncate the packet down to the RFC-specified 32-bit IPv4 address and your reply packets will end up getting routed to China somewhere.

The problem is this: whatever protocol you put in to replace IPv4, most of the infrastructure on the Internet will have no idea what to do with it. That means it's virtually impossible that you'll ever be able to seamlessly bridge between stupid old ignorant IPv4 routers and the more aware routers.

What you could do is have routers that nicely bridge between IPvA and IPv4. So you send out an IPvA packet and it magically finds its way to a router that speaks both IPvA and IPv4 and can nicely bridge between them. That would be cool, and in fact, I've just described to you how 6to4 works.

Truth be told, even you sat down and came up with a new protocol that was designed for nothing else but bridging between codgy old IPv4 routers and some kind (any kind!) of new Internet protocol, I doubt you could do better than IPv6 and its cohorts (6to4, 6over4, 6in4, 4in6, etc.)

Maybe I'm missing something, but if you're going to make this complaint, you're going to have to come up with something better than "they didn't think about backwards compatibility". They did think about backwards compatibility and they did it in the best way possible from what I can tell.

Re:Laches: the doctrine of you snooze, you lose

[Overzeetop]

Never, or in more practical terms, less than 6 years after the expiration of the patent. Patents need not be defended like trademarks, and you can "back sue" for up to 6 years of infringement. There was a recent story on /. about a company that bought a little known patent right before it expired, then went about suing everybody and anybody for infringement *after* the expiration, but going back 6 years for damages.

Re:Why is 127.0.0.1 in a class A?

[Sloppy]

I could explain this to you, but I would have to write a science fiction novel to do it. Well ok, I'll summarize the novel. Just remember this is a selective summary; pretend that all sorts of really cool things are happening and my characters are totally interesting and the plot is fucking fantastic. Can you do that for me, Wowbagger? Ok.

In an alternate universe, the IP4 designers did just as you suggest, and the loopback network was Class C. In this alternate universe, other things went in a different direction too. By 2010 we all have CPUs with thousands of cores, but they all run at 1 MHz and programmers discuss ways to improve the linearization of their code.

And we all have a weird crippled piece of shit operating system, which got popular despite all its limitations. (This may seem hard to believe to us, but remember I'm talking about an alternate reality.) One of its limitations, is that its networking code doesn't deal with port numbers, because the designers thought that was a waste of 16 bits. (Computers in this reality have about as much memory as what we're used to, but there are more addresses and the words are 4 bits wide, so working with 16 bit data is kind of a pain in the ass.) Another of its limitations is that is has no IPC as we currently know it. Fortunately in the 1990s some programmers "invented" IPC by having each process use the loopback network, but since there are no port numbers, each process has to have its own address on the loopback network so that the OS can sort out what process gets what message. This inevitably led to mocking jokes:

"255 loopback addresses ought to be enough for anyone." -- Vint Cert

There were terrible hacks for running hundreds of processes and having them all be able to talk to one another, where a proxy process would emulate a sub-loopback network for 254 other processes and present a single loopback address to the OS. It was such a broken, terrible system, that it delayed the popularization of personal computer networking, so there was no "mainstream" use of the internet and the supply of IP4 addresses lasted much longer. In 2010, there was no non-loopback address shortage; it wasn't expected for another decade.

Then one day a poster named whoasacker got on Hyphencolon and asked, "Why didn't they just use a Class A network for the loopback?" And a poster named Slippery answered, explaining, "In an alternate universe, they did..."