IV. server placement (cont.)

macroscopic topology measurements

CAIDA skitter tool
http://www.caida.org/tools/measurement/skitter
traceroute-like methodology
increments Time-To-Live (TTL)
ICMP echo requests
small (52-bytes) probe packets
slow-paced

probes measure
IP forward path information
round trip time (RTT) to destination
thousands of destinations

resulting data
hundreds of thousands of paths per day, for years
most comprehensive macroscopic Internet topology data