Capturing ghosts: predicting the used IPv4 space by inferring unobserved addresses

摘要: The pool of unused routable IPv4 prefixes is dwindling, with less than 4% remaining for allocation at the end June 2014. Yet adoption IPv6 remains slow. We demonstrate a new capture-recapture technique improved estimation size "IPv4 reserves" (allocated yet addresses or prefixes) from multiple incomplete data sources. A key contribution our approach plausible both observed and unobserved-yet-active (ghost) address space. This significantly improves community's understanding space exhaustion likely pressure adoption. Using "ping scans", network traces server logs we estimate that 6.3 million /24 subnets 1.2 billion are currently in use (roughly 60% 45% publicly routed respectively). also show how utilisation has changed over last 2--3 years provide an up-to-date potentially-usable