Today is World IPv6 launch day, when several large Internetservices turn on IPv6 addressing - hopefully on a permanent basis.What is IPv6, and what does it mean for you and your gear? June 6, 2012, is World IPv6 Launch Day , when several leading Internet sites and services are permanently enabling access via the Internet's latest addressing format,Internet Protocol version 6, or IPv6. Comcast, Yahoo, MicrosoftBing, Facebook, Google and many others are all on board, along withgear makers like Cisco and D-Link. If everything works out and,likely, most everything will these services will represent theforefront of the next phase of the Internet. Eventually, everything connected to the Internet will be using new-style IPv6addresses. This doesn't mean Facebook, Google, Yahoo and other siteswill suddenly disappear today if you aren't using IPv6. |
Infact, if everything goes well you shouldn't notice any changeat all. But IPv6 is not backwards compatible with the Internet's current addressingscheme, IPv4, and, eventually, you will have to use it, like it or not. What IP addresses do Right now, essentially every machine connected to the globalInternet communicates with other systems using Internet Protocolversion 4, or IPv4. These IPv4 connections happen at a much lowerlevel than, say, connecting to a website or logging in to an onlinegame: IP connections are the building blocks on which all otherInternet connectivity is based.
In a nutshell, when you connect toa website or upload your latest photo, Internet Protocol isresponsible for breaking that data up into pieces, putting anaddress label on every piece, and sending them along towards theirdestination. While the data is en route to or from you, a number ofdifferent systems gateways, proxies, routers, and more lookat the address information on each of those packets, and forwardthe data to the next hop on a chain that will (eventually) lead tothe correct destination. If it everything goes well, all those intervening systems aretransparent. Systems can behave as if there is a direct connectionbetween them, when in fact there could be a large number ofintervening routers and systems.
Those IP address labels are acritical part of how this communications works. Where did the old system come from? The current IPv4 system was created by Bob Kahn and Vint Cerf seen at right and widely known as the "Father of theInternet." The scheme was first presented to the technologycommunity back in 1973. Computers all operate in terms of bits andbytes those infamous ones and zeroes that movie and televisionproducers love to wash across their visuals in order to convey anotion of technical wizardry. Bits can have just two values, andprocessors and memory tend to prefer to deal with bits in chunksthat can be represented as powers of two and that are evenlydivisible by eight (or better still, multiples of eight mostmainstream computer CPUs these days are 64-bit).
So, when Kahn andCerf proposed the first version of Internet protocol, they proposeda 32-bit field for system addresses. At the time the early 1970s 32-bit addresses weretremendously forward-thinking. They were small enough to beprocessed and stored efficiently, but offered enough "addressspace" for unimaginable possibilities. Bits can have twovalues (zero and one) so a 32-bit field can have 2 32 possible combinations theoretically, that meant the IPv4network could handle over four billion (4,294,967,296) systems!That was essentially an infinite number back in the early 70s, whenpersonal computers had a few kilobytes of RAM, time-sharing was theorder of the day, and mainframes and minicomputers had price tagsin the five and six figures and required dedicated support staffsto operate.
There weren't even four billion people on Earth! Even setting aside whole swaths of addresses for network managementand testing purposes, 32-bits still left oodles more addresses thananyone knew how to use. And back in the early days, addresses werehanded out willy-nilly: At one point, Apple Computer hadwhat's called a Class-B address space, which was equivalentto 1/256th of the entire Internet. That's more than manycountries have today. (And, yes, Apple wound up giving back themajority of those addresses.) So what is IPv6? When worldwide use of the Internet exploded in the 1990s coinciding with the birth of the Web it became obvious that,eventually, 32-bit addresses weren't going to offer enoughaddress space. Part of the issue is network management.
Every timeyou subdivide a network, only a portion of the addresses areusable; the rest are lost to gateways and routers and broadcastaddresses. Most of the pressure was from businesses, organizations,and ISPs all over the world rushing to get online and allwanting their own address space. The issue finally came to a headin February 2011, when the International Corporation for AssignedNames and Numbers doled out the final unassigned blocks of IPv4 address space . IPv4 addresses are now a limited, increasingly scarce commodity.Just a month later, Microsoft paidd $7.5 million to acquire a large unused block of IPv4 addresses that hadbelonged to bankrupt telecommunications company Nortel.
By 1996, the IPv6 addressing standard had been finalized. (Yes:IPv6 is already 16 years old!) In essence, IPv6 expands the size ofInternet addresses from 32 bits to 128 bits. That might seem like afour-fold increase in the possible size of the Internet 32 4is 128, right? but that's not the way bits work. Everytime you increase the length of a bit field, you square the number of values it can represent. One bit can represent twovalues that's 2 1.
Two bits can represent four values (2 2 ), three bits can represent eight values (2 3 ), and so on. By the time you get to 2 128 , you've reached340,282,366,920,938,463,463,374,607,431,768,211,456, or more than340 undecillion. There's a bunch more to IPv6 than larger addresses including support for encryption and quality-of-service metrics,better multicasting support, a new datagram format, improvedrouting support, and technology to automatically reconfigure hostsand IP addresses on a network. But the driving force behindadopting IPv6 now is the larger address space. What do IPv6 addresses look like Folks who've been using the Internet for a while are probablyfamiliar with IP numbers: a series of four numbers separated by dots that uniquely identifya device on the Internet.
One address Digital Trends currently uses is 22.214.171.124 this is called dotted-quad or dotted-decimal format. Each number represents eight bits in the 32-bit field inan IPv4 address. As a result, each number will range from zero to255: if you see a dotted-quad (say, on TV) with a number largerthan 255, it's utterly invalid (and therefore fake). While the technically adept can easily remember significant bareIPv4 addresses like 126.96.36.199 , IPv6 addresses have a lot more numbers, so it'll be muchmore important to be able to identify systems and devices on anIPv6 network by name. But so you know what they look like, IPv6addresses can be represented by a sequence of hexadecimal numbersseparated by colons.
(Hexadecimal is base-16, written using thenumerals zero through 9 and the letters A through F. Why base-16?Remember how computers like things that are powers of two anddivisible by eight. Using hex also allows you to represent largenumerical values in fewer characters: four digits in hex canrepreset up to 65,536 in decimal.) So, an IPv6 address might look like this: 0123:4567:89ab:cdef:0123:4567:89ab:cdef Each sequence of four hexadecimal digits is called a"hextet" that's actually short for"hexadectet." Each hextet represets 16 bits, so an IPaddress can have up to eight hextets. However, if a particularhextet starts with a zero, you can omit that leading zero. If asingle hextet (or single sequence of hextets) are all zeros, you can omit them and use a double colon.
In the figure above, the dotted quad IP address is for Digital Trends, but the IPv6 address is for ipv6.weather.yahoo.com. See the sequence of fields that are all zeros? Following the rulesabove, that can be shortened down from this: 2a00:1288:f006:01fe:0000:0000:0000:1000 all the way down to: 2a00:1288:f006:1fe::1000 How IPv6 and IPv4 coexist World IPv6 Launch Day doesn't mean that the entire Internetis turning off IPv4 addressing today and switching entirely to IPv6addressing that would be disastrous! Although IPv6 can use the32 bits in an IPv4 address to make form an IPv6 address, at afundamental level IPv6 is not backward compatible with IPv4. No IPv4 system or device can function on an IPv6network. For the entire Internet to run IPv6, every system anddevice will have to be upgraded to IPv6. That will take many years to hazard a guess, at least a decade.
But the transition isstarting: the significant of today's World IPv6 Launch Day isthat major services hope to permanently enable IPv6 more and more will be doing the same as time goeson. So, the reality remains that the vast majority of the Internet isstill running IPv4, and will continue to do so for some time tocome. For now, networks operating with IPv6 are effectivelyisolated islands within a sea of IPv4 networks. They can use IPv6on their own networks, but if they want to communicate with IPv4networks or, in most cases, even with other IPv6 networks they're going to have to down-convert to IPv4 or tunnelthrough IPv4 networks to communicate.
Effectively, IPv6 networksare running both the IPv4 and IPv6 protocols side by side. The figure above illustrates some simple relationships between somehypothetical networks. Right now, the majority of networks run IPv4and communicate with each other using IPv4 you can seethere's only one case where networks are communicating with each other exclusivelyvia IPv6 meaning they're both running IPv6 internally and communicating with another network without relying on an IPv4network to transfer data between them. Eventually, this diagram will reverse: The IPv6 networks willbecome larger, the links between them will no longer rely on IPv4,and networks that operate exclusively on IPv4 will becomerelatively isolated islands.
Networks and systems that can only useIPv4 will not be able to reach IPv6-only networks and sites and,since the IPv4 Internet is rapidly running out of address space,that day may not be far off. What you'll need to do eventually Here's the good news: IPv6 technology is already 16 yearsold, and network operators have been able to set up IPv6 networkssince 1999. Further, the majority of modern operating systemsalready have built-in support for IPv6: this includes versions ofWindows going all the way back to Windows XP (sort of), mostversions of Mac OS X, as well as iOS and most Linux distributions. Of course, there are caveats.
For instance, IPv6 on Android devices even ones running Ice Cream Sandwich is currently limited toWi-Fi connections, and Apple's Mac OS X tends to prefer IPv4addressing even when a network advertises IPv6 is available. (Thereasons are complicated, but amount to the fact a number of thingsadvertising IPv6 capability like Windows systems sharing theirnetwork connections don't actually provide it). Now the bad news. Most ISPs don't offer IPv6 connectivity totheir customers even if they're starting to use it ontheir own networks so even if you're savvy enough to setup IPv6 on your own, the odds are good that you'll betunneling down to IPv4 as soon as you try to connect to the broaderInternet. And there's more bad news: Remember how IPv6 is not backwardcompatible with IPv4? That applies to every device in theconnectivity chain between you and any destination on the Internet.For a connection to operate completely on IPv6, not only does yourtablet, phone, or computer have to be running IPv6: every devicebetween you and your destination has to be able to handle IPv6traffic as well.
That includes things like Wi-Fi base stations,cable modems, DSL routers, and 3G/4G network providers. Convertingto IPv6 means all those devices will have to be replaced or upgraded to handle IPv6. So, what will you have to do to start using IPv6? For mostconsumers, there's no point worrying about it until theirISPs start to make IPv6 services available. For some folks,that's already a reality: Comcast says it already has onepercent of its customers running IPv6, but other ISPs haven'tbegun to transition customers to IPv6 at all. Once IPv6 service is available, the next step is making sure theoperating systems on their devices supports IPv6, then updating orreplacing things like their broadband routers and Wi-Fi basestations to support IPv6.
In all probability, users will beupgrading to routers and base stations that support both IPv4 andIPv6 that way, they can continue to use devices like gameconsoles, ereaders, cameras, set-top boxes, Internet-capable TVs,and hand-held gaming systems that rely on IPv4 even if thosewon't be able to connect to IPv6-only sites and services. Should you worry? For now, there's no need to panic. Despite the fact that theIPv4 address space has all been allocated, there are still enoughunused IPv4 addresses out there to fuel Internet growth for a while perhaps a few more years. However, IPv4 addresses are gettingscarcer, and the speed of the IPv6 transition could potentiallymake the price of IPv4 addresses rise substantially — thecost of running a server or "being on the Web" could goup.
IPv4 functionality can also be extended with technologies likeNAT routing (which effectively tuck a separate IPv4 address spacebehind a single IPv4 address); however, those approaches have theirlimits and aren't suited to every Internet application. But IPv6 is coming, and one day we'll be talking about IPv4the same way we talk about dial-up Internet today. Image credit: Shutterstock / Sabino Parente.
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