IPv6 carried half of global traffic for a single day in March, according to Google.
The search and ads giant tracks the percentage of its users who access its services over IPv6 on a page that The Register has often seen used as a de facto indicator of all IPv6 uptake when we attend networking and internet governance events.
According to the Big G’s stats, on March 28th, 50.1 percent of the traffic the company detected used IPv6, up from 46.33 percent a year earlier. Google’s data records plenty of days over the last year when IPv6 carried over 49.5 percent of traffic, and a slow climb towards greater prevalence of traffic using the protocol.
Google has a decent view of the internet because its main domain and YouTube are the world’s two most-trafficked websites.
However, other sources don’t currently report IPv6 at 50 percent of visible traffic.
Cloudflare’s Radar service, rates IPv6 as the source of 40.1 percent of HTTP requests. APNIC labs found 43.13 percent of networks it can see are IPv6-capable.
Google’s result is therefore notable, and nice, but not solid proof that IPv6 has finally become dominant.
Internetworking boffins conceived of IPv6 after realizing IPv4’s 4.3 billion available addresses would be insufficient to service the growing number of internet-connected devices. They therefore designed IPv6 around 128-bit addresses, meaning the IPv6 numberspace offers 340 undecillion addresses – 340 followed by 36 zeroes.
That vast quantity of addresses is probably enough to allow humanity to assign a unique identifier to every connected device our species will create between now and the heat-death of the universe – and give an IP address to plenty of the stars that are born and die along the way.
The effectively unlimited availability of IPv6 meant pundits assumed network operators would swiftly adopt the protocol, especially after the pool of available IPv4 addresses dried up in the mid-2010s.
Many therefore regard slow uptake of IPv6 as curious.
As The Register has reported, two main factors retarded IPv6 adoption.
One was that the protocol didn’t add many useful features, so network operators didn’t rush to adopt it.
The other was the advent of network address translation (NAT), which allows many devices to share a single public IPv4 address. Many organizations with IPv4 holdings used NAT to increase their capacity rather than build a new network on IPv6, slowing uptake of the newer protocol.
Some nations, however, passed 50 percent IPv6 adoption years ago. That’s an artefact of the loose governance that prevailed in the early years of the internet’s growth and allowed developed nations to scoop big pools of IPv4 before other countries could stake a claim. Nations like India and China therefore gained insufficient IPv4 resources to serve their populations and drove for IPv6 adoption instead. The 29 nations in Asia and Oceania served by the Asia Pacific Network Information Centre therefore passed 50 percent IPv6 in 2025. The American Registry for Internet Numbers, which serves 29 nations across North America and the Caribbean, reached 50 percent adoption a couple of years earlier. ®