Under the Hood: Network implementation for World IPv6 Launch

What this post added

This post details the implementation of Layer 3 DSR with IP-in-IP tunneling for IPv4 and IP6-in-IP6 tunneling for IPv6 to support World IPv6 Launch. It describes the challenges of moving beyond single Layer 2 domains to Layer 3 clusters and the specific kernel patch developed to enable IPv6 tunneling on fallback devices. The post highlights the importance of IPv6 for future internet scalability and the successful integration of IPv6 into Facebook's infrastructure.