Due to a formatting error, the 11th paragraph of the story, "Usenix: Google deploys IPv6 for internal network," contains incorrect information about the number of addresses on IPv6 networks. That paragraph has been changed and now reads:

To assign IPv6 numbers to devices, Google followed the guidelines in the Internet Engineering Task Force's RFC 5375. Each campus or office got a /48 address block, which meant that it was allotted 2 to the 80th power addresses. In turn, each building got a /56 block of those addresses (or about 2 to the 72nd power addresses) and each VLAN (Virtual Local Area Network) received a /64 block, or about 2 to the 64th power addresses. To assign numbers to specific devices, the engineers used the Stateless Address Auto-Configuration capability (SLAAC), which allows the devices to assign numbers to themselves. This approach eliminated the need to manually assign numbers to each device. It was also necessary in that at least some operating systems do not yet support DHCPv6, the version of Dynamic Host Configuration Protocol server-based addressing mechanism for IPv6 networks.