(Strength1): By combining peering richness and geographic information,
this graph clearly reveals the highly
connected nature of ASes.
Of the top 15 ASes, 14 are based in the U.S., and one is based
in Canada. While ISPs
in Europe and Asia have many peering relationships with ISPs in
the U.S. there are few links directly between ISPs in
Asia and Europe.
(Issue1): Each AS headquarters reflects an administrative home, not
geographical location of actual infrastructure. (which is typically
national or global).
(Issue2): Graph does not reflect current conditions. More studies are needed to determine an appropriate sampling rate. (CAIDA hopes to have a daily update available by December 2000.)
(Issue3): Graph only represents forward IP topology information, with
IP addresses mapped to origin ASes using a BGP routing table. Other information
about peering sessions is not reflected.
(Issue4): IP layer only, does not capture
lower layer (e.g., ATM, physical fiber) information.
(Issue5): Graph doesn't address any performance or workload
precluding comparison of ISPs in these dimensions.