Since the official IPv6 launch day seven years ago in June 2012 (, the deployment of IPv6 within network providers has rapidly accelerated with an estimated 80-90% deployment of IPv6 within their networks (usually running in parallel with ‘traditional’ IPv4 networking).  However the data volumes using IPv6 over commercial networks is still estimated to be incredibly low. As an example the Amsterdam Internet Exchange (IX) transfers an average of 3.7 Terabits per second, of which less than 3% is IPv6 traffic.

By contrast, research and education networks have not only embraced IPv6 deployment but are seeing substantial increases in traffic using IPv6.

GÉANT implemented IPv6 across the whole network over ten years ago with 100% of the network now fully enabled, and the deployment of IPv6 across NREN networks is rapidly expanding.

In April 2018 the GÉANT network was transferring an average of 20Gbit/s of IPv6 traffic (approximately 6% of total traffic) and only 12 months later this has increased to an average of 110Gbit/s or 22% of total traffic – an increase of 5.5 times

Detailed analysis of this increase is still ongoing, but the IPv6 traffic flows appear to be more consistent and not as subject to either the weekly peaks and troughs of IPv4 traffic or the more seasonal variations across summer and Christmas. This would indicate that this traffic is more closely associated with the many ‘big science’ projects that use GÉANT’s network to transfer and share data – suggesting it is more black hole data than black cat videos!

Whatever the true cause of the rise in IPv6 traffic, it is clear that GÉANT and the NRENs are likely to see even more growth in the future as both big science requirements ramp up and institutional traffic increasingly migrates from v4 to v6.

Annual increase of IPv6 traffic across the GÉANT network.


These changes in both traffic patterns and profiles will help GÉANT better understand the trends in R&E networking and assist in the planning and design of the new GN4-3N network over the next few years.