The fraction of general internet traffic carried over IPv6 continues to grow rapidly. The transition of WLCG central and storage services to dual-stack IPv4/IPv6 is progressing well, thus enabling the use of IPv6-only CPU resources as agreed by the WLCG Management Board and presented by us at CHEP2016. By April 2018, all WLCG Tier 1 data centres will provide access to their services over IPv6. The LHC experiments have requested all WLCG Tier 2 centres to provide dual-stack access to their storage by the end of LHC Run 2.
For several years the HEPiX IPv6 Working Group has been testing WLCG services to ensure their IPv6 compliance. Many Tier 2s are now successfully running their services in dual-stack mode, but there is still a large number who are not. The working group, driven by the requirements of the LHC VOs to be able to use IPv6-only opportunistic resources, continues to encourage wider deployment of dual-stack services and has been monitoring the transition.
We will present the progress of the transition to IPv6. This includes making experiment central services dual stack as well as the storage and data services. The monitoring, accounting and information services that are used by jobs are also being upgraded. Finally, we will assess the timetable for being able to turn off IPv4 completely at a WLCG data centre, this being the point at which the transition can be declared truly complete.