IV. server placement: nameservers by geography clusters of root servers 2/3 of NA dsts have lowest mRtts to servers in US-E family, other 1/3 to US-W majority of European dsts best-served by Europe family, with some in US-E a few Asian dsts favor Europe and US-W family Oceania prefers US-W family note data missing from 3 root servers but likely not result-changing