topology:  caida's skitter

track/depict topology cross-sections 
22 monitors (inc. some root name servers)
forward IP path and round-trip delay 
tens of thousands of dst (mult. lists)
remove targets that complain
150k nodes, 270k links in 5 days (11/99)

architecture
continuous, parallel 52-byte ICMP probes
depending on dst list size, O(1) probes/hr/dst
kernel time stamping

correlate path perf. w events, e.g. BGP
identify critical pieces of infrastructure
case studies of relevant cross-sections