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Dispelling the IPv4 Address Shortage Myth
Zocalo writes "While looking up some WHOIS information at RIPE just now I noticed a couple of articles about the IPv4 address space allocation status. IPv4 Address Space: October 2003 is a short summary by RIPE themselves, and IPv4 - How long have we got? is from July 2003, but has lots more detail and pretty graphs!
In short, the "Death of the Internet" due to lack of IP space is a myth, which doesn't bode well for getting IPv6 rolled out any time soon."
I enjoyed both of the articles. The question I have is this. With the number of networks now being NATed and the such, will we ever truly need something like IPv6? It seems like whe I hear about it, the talk is always that every device will have a unique IP address. But what I see is that large deployments of devices needing IP addresses are more and more being done using 192.* or 10.* addresses. Anyone else have more insight?
Random Musings
This message was posted on a mailing list in response to a post that claimed that IPv6 would be widespread by 2005 due to an IPv4 address shortage
NATs, unfortunately, made a need to switch over to IPv6 wholly unnecessary. Such a switchover will probably not happen for at least another ten years. Even ten years ago, we were "running out of" IPv4 space due to incredibly inefficient allocations using the "class based addressing" method - by which your network was deemed to either to likely possess 253 computers, 65,533 computers, or 16,777,213 computers. A specific network was identified by 24, 16, or 8 bits. (The more bits it takes to identify a network, the more networks can exist but at the expense of having fewer unique addresses per network.)
This was quickly determined to be an inordinate waste of addresses and as early as the early 90's folks were predicting we'd rapidly run out of addresses. So class allocations changed a little, and instead of giving an organization with 1000 computers a class B (with 65,533 useable addresses), they'd give them four class C's (with 1012 addresses). This helped stem the tide for a bit and arguably saved the Internet's ass, but it was clear that a more elegant system for identifying networks was needed.
After some backbone technology re-architecting, a new scheme called Classless Internet Domain Routing, or CIDR was introduced, which allowed bit-sized granularity, meaning that a network was identified by exactly as many bits as you needed. Your network could possess 13 computers, or 16,381 computers, and the system could deal with that efficiently. CIDR definitely also helped save the Internet's ass. But the addresses kept on coming; that dang Internet was getting popular very quickly! Pundits started talking about The Great IPv6 changeover, despite the fact that less than one person in 100 on the Internet had an IPv6-enabled operating system.
Then came NATs. While Network Address Translation had been used in many environments, it hadn't really taken off tremendously. Then Linksys released a rather affordable cute little blue box. This piece of hardware let home users plug in several computers to the blue box, configure it with a web interface, jack in their cable/DSL connection and suddenly be sharing Internet access easily with everyone in the house, using one IP address and so fooling the ISP into thinking that there was only one computer using the Internet (many ISPs either don't permit or don't have the infrastructure to give out multiple addresses to a customer). These NATs had a secondary benefit, which was that by default, all incoming connections from the outside are dropped on the floor. I'm not sure Linksys had such "firewalling" in mind when originally designing the device - it's purely a practical issue. I mean, if someone says to a NAT "here's this piece of information" - to who which of the four connected computers should the NAT send it? By default, the NAT will give up and just drop the sorry packet. This means that when you're behind a NAT, you're protected from a whole class of Internet attacks. This realization further drove adoption.
Companies with low IT budgets realized that they wouldn't have to buy extra IP addresses from their ISP (which often came at a premium) and that they could have simple firewalling without a complex configuration. Both companies and people could not see the inherent value in having each of their computers have an Internet-deliverable address, and there was real value (protection) to be had in NOT be addressable from the Internet.
This, again, saved the Internet's ass. Instead of an organization of 1000 needing a class B, wasting hundreds of thousands of IPs, or even four Class Cs, this organization now only needs a single IP address to cover all of its desktops. Now instead of thinking about IP addresses as computer addresses, they have started to become network addresses, which is to say,
La via sola al paradiso incommincia nel inferno
I thought the current issue with IPv4 was not the limited number of ip addresses, but the increased routing tables brought on by classless routing? These days, the central routers on the Internet have routing tables which are huge, which must cost someone somewhere to upgrade them.
IPv6 was supposed to deal with this issue as much as it dealt with the number of ip addresses available, in that it would revert back to a semi class based routing set, with ISPs being assigned a range of addresses.
Thats how I understood it when I asked anyhow.
IPv6 will eventually be adopted, because the way IPv4 addresses are allocated, many regions of the world *do* have a shortage of addresses. In particular, Asia has a serious shortage of IPv4 addresses. In fact, I know of people who run IPv6-only machines in Japan (because there are 6to4 addresses that allow you to reach IPv4 servers with approximately the same functionality as NAT).
Moreover, as people deploy new infrastructure, they may be forced to use IPv6. For example, at some point every cell phone is going to have a routable IP address--and that is definitely going to require IPv6.
So while North American desktop machines are unlikely to be switched to IPv6 any time soon, it will happen in other parts of the world and for other types of hardware.