The upcoming World IPv6 Day is the biggest event in the history of IPv6, a 13-year-old standard of which the primary advantage over IPv4 is an expanded addressing scheme. While IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet, IPv6 uses 128-bit addresses and can connect up a virtually unlimited number of devices: 2 to the 128th power.
The Internet needs IPv6 because it is running out of IPv4 address space. The free pool of unassigned IPv4 addresses expired in February, and in April the Asia Pacific region ran out of all but a few IPv4 addresses being held in reserve for startups. The American Registry for Internet Numbers (ARIN), which doles out IP addresses to network operators in North America, says it will deplete its supply of IPv4 addresses this fall.
DETAILS: Asia out of IPv4 addresses
But as necessary as IPv6 seems, there is a major stumbling block to its deployment: It's not backward compatible with IPv4. That means network and website operators have to upgrade their network equipment and software to support IPv6 traffic, and so far most have been unwilling to do so.
Despite all of the network industry momentum around World IPv6 Day, the protocol is not taking off on the Internet anywhere near as fast as proponents had hoped. A recent survey of Internet traffic compiled by Arbor Networks found that IPv6 represented less than 0.2 percent of all Internet traffic. Indeed, Arbor said IPv6 traffic -- both tunneled and native -- had declined 12 percent in the last six months, even as momentum for World IPv6 Day was building. Arbor gathered this data by surveying six carriers in North America and Europe.
Craig Labovitz, chief scientist of Arbor Networks, says the decline in IPv6 traffic is the result of users replacing inefficient IPv6-over-IPv4 tunnels with native IPv6 traffic, which he says is a sign of IPv6 becoming more production ready.
Although he concedes that the IPv6 migration effort has been unsuccessful to date, Labovitz said he is hoping that World IPv6 Day will change the protocol's momentum.
"My biggest hope for IPv6 Day is that the large content providers will gain enough confidence to leave IPv6 ... on by default,'' he says. "If this happens, we will have broken through the Catch-22 of subscribers/enterprises waiting for content, and content waiting for subscribers/enterprises to deploy IPv6."
If IPv6 adoption continues to lag, Labovitz warns that events may overtake the Internet engineering community.
"Instead of planned and well thought-out evolutionary Internet architecture, we end up with market forces creating a swamp of workarounds, hacks and other problems that add expense, stifle innovation and limit the potential of this fantastic global network," Labovitz predicts.
In contrast to the Arbor Networks data, NTT America reports increasing demand for the new protocol from its telecom, IT, hosting, government and education customers. NTT says 30 percent of its customer ports and 70 percent of its peering ports are now IPv6 enabled.