...
We selected 4 landmarks in North America for our study( SLAC, BNL, Ampath-Florida,TRIUMF-Canada). We pinged a set of know geographical sites from PingER database in US, Canada and Mexico. We also calculated the physical distances between them. The figure below shows the distribution. It appeared that all hosts were within 80ms of one another of the 4 monitors and 98.84 are < 70ms.