Performance Implications of Unilateral Enabling of IPv6

While some IPv6-enabled Web sites such as Google require an explicit opt-in by IPv6-enabled clients before serving them over the IPv6 protocol, we quantify performance implications of unilateral enabling of IPv6 by a Web site. In this approach, the Web site enables dual-stack IPv4/6 support and resolves DNS queries for IPv6 addresses with the IPv6 addresses of its Web servers, and legacy DNS queries for IPv4 addresses with the IPv4 addresses. Thus, clients indicating the willingness to communicate over IPv6 are allowed to immediately do so. Although the existence of the end-to-end IPv6 path between these clients and the Web site is currently unlikely, we found no evidence of performance penalty (subject to 1sec. granularity of our measurement) for this unilateral IPv6 adoption. We hope our findings will help facilitate the IPv6 transition and prove useful to the sites considering their IPv6 migration strategy.