World IPv6 Day, 6 June, 2012 is here, and with it many ISPs, websites and manufacturers are now supporting IPv6, the next generation network protocol of the internet.

For many users, though, the questions of what, when and why still await answers.

Everyone in networking knows that they should be switching to IPv6. The Internet Engineering Task Force (IETF) realised that in 1994, when it predicted that IPv4's 4.3 billion addresses wouldn't be enough. Its answer was IPv6. With its 128-bit address space it can have up to 2^128 addresses — that's 40,282,366,920 billion billion billion usable addresses. Even an interstellar internet won't run out of numbers any time soon.

Meanwhile, back on Earth, the regional internet registries (RIRs) in charge of parceling out IP addresses are down to their last old-style IPv4 addresses. Indeed, the Asia Pacific Network Information Centre (APNIC) ran out of IPv4 addresses in April 2011. RIPE NCC, Europe's RIR, will be the next to run out sometime in August. In North America, the last IPv4 address will be assigned in June 2013.

That will be the end of the road for new IPv4 addresses. Technologies like Network Address Translation (NAT) and Classless Inter-Domain Routing (CIDR) that let us run multiple devices behind a single IP address have won us some time, but while neither NAT nor CIDR will be going away soon, they can't delay the IPv4 famine any longer.

Not so straightforward

Yet a straightforward switchover can't happen because IPv4 and IPv6 aren't compatible protocols. Dual network stacks that support both protocols will be necessary for the foreseeable future.

Vint Cerf has described the delay in IPv6 implementation as "understandable but inexcusable". Photo credit: David Meyer

Vint Cerf, one of the fathers of the internet and the man who takes responsibility for IPv4's "inadequate" number of addresses, told CNET News's Stephen Shankland in an interview that he'd "hoped for much earlier implementation [of IPv6]. "It would have been so much easier. But people had not run out of IPv4 and NAT boxes were around (ugh), so the delay is understandable but inexcusable. It is still going to take time to get everyone on board," Cerf said.

Another reason why IPv6 adoption has been so slow is the classic chicken-and-egg problem of which comes first, the technology or the users.

As Bob Hinden, co-inventer of IPv6 and a fellow with Check Point, the network security company, explains: "The problem that IPv6 solves is it provides a larger IP address space than IPv4. However, no one gets the full benefit of IPv6 deployment until everyone supports it. There was little incentive for organisations to adopt IPv6 as long as they could still get IPv4 addresses.

"In essence, organisations delayed investing in IPv6 until they absolutely had to. However, the pool of unallocated IPv4 addresses is close to being exhausted with the last block of free IPv4 addresses assigned on January 2011. IPv4 addresses are now much harder to get for most enterprises, and large blocks needed by ISPs are close to impossible to obtain. So now, organisations are waking up to the need to deploy IPv6, and we're seeing wider acceptance."

Who's on board IPv6 today?

How much wider acceptance of IPv6 is there really? Craig Sprosts, general manager of Fixed Broadband Solutions at Nominum, a network services company in Redwood City, California, has these findings from a survey of 67 ISPs, providing internet service to over 110 million US households. Nominum's survey "found that 97 percent of these companies have implemented or plan to implement IPv6; 23 percent have already done so, 35 percent plan to do so this year and 39 percent plan to do so in 2013 or later".

That sounds good, and there has been growth in IPv6 traffic. Hurricane Electric, an IPv6 ISP and backbone provider with a claimed 58.6 percent of the world's IPv6 networks, states that IPv6 internet traffic has grown over 150 percent since 2011's Global IPv6 Day.

No one gets the full benefit of IPv6 deployment until everyone supports it. There was little incentive for organisations to adopt IPv6 as long as they could still get IPv4 addresses. – Bob Hinden

On the other hand, Burt Kaliski, CTO of VeriSign (operator of the root DNS [Domain Name Service] servers and the .com and .net registries) says that while IPv6 DNS traffic has tripled over the last year, "we're not seeing a significant increase in the percentage of transactions carried over IPv6 for .com and .net and it has been relatively flat over the last year".

No matter how you measure it, IPv6 traffic is still a tiny fraction of the global internet traffic.

Indeed, Leslie Daigle, chief internet technology officer of the Internet Society, confirms that the goal for World IPv6 Day was to provide only one percent of users with IPv6 access. This "is enough traffic to demonstrate that access providers are well advanced in their actual deployment plans. With that, and the fact that content providers are turning on IPv6 and leaving it on for this year's challenge, we have the basis for our statement that: this time it's for real; after June 6 2012, IPv6 is the new normal for Internetworking".

Why only one percent? It's because the Internet Society knows most people aren't ready yet. Daigle explains: "The goal is to reach one percent by June. In many cases, users may need to upgrade or replace hardware and software, such as operating systems or home routers, to use IPv6. Over time, as users upgrade, IPv6 adoption will increase without any changes in the ISP's service or equipment."

So why should you upgrade?

With less than one percent of internet connectivity, you may not find the case for upgrading to IPV6 compelling.

Yet, while the traffic may not be there yet, major websites are moving to dual-stack network solutions. Erik Nygren, chief architect for Akamai, a content delivery network (CDN) company, says: "Akamai has IPv6-enabled over 50 major websites belonging to over 20 of the world's largest web companies that participated in last year's World IPv6 Day event. The company anticipates traffic levels will continue to increase as more customer sites dual-stack in the period following this year's World IPv6 Launch where over one-third of the top 30 registered sites by Alexa rank will be using some of Akamai's IPv6 services."

Nygren continues: "As of May 18 of this year, over 700 US government sites across 21 agencies were permanently dual-stacked using Akamai's services as the company continues to help their customers meet the US federal government mandate (PDF) requiring all public-facing government sites to be enabled for IPv6 by the end of September 2012."

With Facebook, Google and Yahoo also moving to IPv6 there will be...

...sites that IPv6-enabled users can reach. Of course, they'll still be able to reach them by IPv4 as well. As Sampa Choudhuri, a Cisco small business marketing manager, recently blogged, "Your current network running IPv4-based devices won't be obsolete for some time."

However, as John Curran, president and CEO of the American Registry for Internet Numbers (ARIN), North America's RIR, explains: "World IPv6 Launch Day is a lot larger than people understand. IPv6 is the single largest upgrade in the history of the internet. It's not a small decision for the major content providers to turn on IPv6 and leave it on. Going forward, internet users will be forced to go through transition gateways to reach businesses that do not similarly upgrade by adding IPv6 connectivity, with the result being slower connections and services for their customers."

Those transaction gateways, which slow down traffic, already exist. Alain Fiocco, Cisco's Senior Pv6 Program Director, says, "For a real-world example of IPv6's impact on business-to-consumer services, look to online banking. While a common web service, online banking is actually a complex application that, delivered through IPv4, is bogged down jumping translation hurdles to reach an IPv6 household. Therefore, an IPv4 bank risks losing customers [that] consider a speedy, complex and rich online experience an integral part of the business relationship."

For businesses working with other businesses, Fiocco thinks the need is even greater. "Other industries — particularly in B2B — don't have a choice. Manufacturing companies with partners in IPv4-exhausted regions (eg, China, Vietnam) have already made the switch," he says.

Tom Coffeen, IPv6 evangelist for InfoBlox, a US network services company, agrees. "Given the exhaustion of IPv4 in Asia (with Europe to follow in a few weeks) many newly connected (and all future) internet users will be requesting content from IPv6-enabled devices," he says. "Companies are becoming more aware of the risk to competitive advantage brought on by failing to make their public-facing (ie, internet available) content over IPv6. As a result, the logical scope of IPv6 adoption for most companies will be to get their content online via IPv6.

Increased customer loyalty, higher network efficiency and reduced costs can all be powerful byproducts of the IPv6 transition. – Craig Sprosts, Nominum

"Specifically, for many organisations this will mean configuring one or more web servers with IPv6," Coffeen continues. "In most cases this will be done on the same servers that currently support IPv4, leading to a 'dual-stack' configuration. Of course, the supporting network segment, router and/or firewall will need to support IPv6 as well. Companies that rely on web hosting or a CDN will need to make sure those service providers support IPv6."

Besides, as Nominum's Sprosts notes, since "the transition from IPv4 to IPv6 is a necessity to keep the internet running and growing" you might as well make the best of it. "Operators, content providers and enterprises should not ignore the powerful business benefits associated with the 'new' internet. Things like increased customer loyalty, higher network efficiency and reduced costs can all be powerful byproducts of the IPv6 transition," Sprosts says.

In short, there are business reasons for starting your IPv6 move.

When should you upgrade?

"When? That's the 2^128-address question," says Cisco's Fiocco. "As more and more consumers switch to IPv6 — AT&T, Comcast, Time Warner and other service providers now bring new households online via IPv6 as a matter of course — it would make sense for businesses to provide services and content via IPv6 sooner rather than later."

Owen DeLong, Hurricane Electric's IPv6 evangelist, agrees. "The sooner you start, the better you can plan/prepare. Plan on adding IPv6 to your existing capabilities and maintaining dual-stack for several years." He also warns, "Expect to have to touch everything in your network." That isn't easy.

Security in particular needs careful consideration, with IPv6 adding a whole new interface to the internet to manage and monitor.

As Chris Smithee, Strategic Solutions Architect with Lancope, a network performance and security company, explains: "For those looking to transition from IPv4 to IPv6, it is important to know that it does not happen with a flip of a switch. There are certain steps that need to be taken to guarantee success during the switch."

Smithee continues: "To start the transition, many may decide to run dual-stack networks, which allow for the operation of both IPv4 and IPv6 environments across the same hardware, ensuring no disruption to service delivery. During this process, it is paramount that organisations implement network monitoring technologies.

"Technologies like flow-based monitoring and other network monitoring tools allow IT professionals to gain visibility into upgrade points and observe application behaviour. Though many organisations may not see the IPv6 light, it has never been more important to make the switch, in tandem with using available technologies, to preserve the integrity and security of today's computing infrastructure."

That also means making sure your network equipment vendors can deliver the goods. Chris Crotteau, senior technical engineer at Network Hardware Resaler, US-based sellers of second-hand network gear, warns: "Describing a device as IPv6 capable does not necessarily imply that the unit has the needed IPv6 features called for by any particular deployment; that a device can process IPv6 traffic at the same rate as IPv4 traffic; or that the system has sufficient resources available to simultaneously process IPv4 and IPv6 traffic."

Though many organisations may not see the IPv6 light, it has never been more important to make the switch. – Chris Smithee, Lancope

Fiocco, however, suggests that your equipment may be up to the job. "If you bought edge routers or security devices within the last three-four years, saddling up for IPv6 is probably as easy as a software update." Otherwise, you're looking at a refresh of your IT infrastructure.

So, according to Fiocco, "The bottom line: if your client is on IPv6, it's in your business's best interest to switch. And with AT&T alone projecting five million [US] households [on IPv6] by the end of 2012, alongside explosive 4G growth, chances are many clients and consumers are getting there, if they are not already."

While IPv6 may still be a trickle today, it's soon going to be a flood, and the sooner you start making the change the better.

Remember, we really are almost out of IPv4 addresses, and by 2013, most new internet services and websites in Asia, Europe and North America will be only reachable by IPv6.