topology mapping project: background


skitter
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

result 
a ton of data (millions of paths per day, for years)
most comphrehensive macroscopic Internet topology data in world
(low bar)