This is an IBM developed process in which client requests via the internet are routed to the cell that is closest to them geographically.
If one or more mirror sites exist, ping triangulation will then use a process called echo location.
With ping or echo, when a server receives a client request it will send out an ICMP (Internet Control Message Protocol) packet across the internet to the mirror sites.
Doing this determines the site that responds most effectively to the client’s request.
In other words, ping triangulation maps the location of the end-user and every mirror site to see which server is open and closest to the user.