  Recently we introduced the rich-club phenomenon as a quantitative metric to
characterize the tier structure of the Autonomous Systems level Internet
topology (AS graph) and we proposed the Interactive Growth (IG) model, which
closely matches the degree distribution and hierarchical structure of the AS
graph and compares favourble with other available Internet power-law topology
generators. Our research was based on the widely used BGP AS graph obtained
from the Oregon BGP routing tables. Researchers argue that Traceroute AS graph,
extracted from the traceroute data collected by the CAIDA's active probing
tool, Skitter, is more complete and reliable. To be prudent, in this paper we
analyze and compare topological structures of Traceroute AS graph and BGP AS
graph. Also we compare with two synthetic Internet topologies generated by the
IG model and the well-known Barabasi-Albert (BA) model. Result shows that both
AS graphs show the rich-club phenomenon and have similar tier structures, which
are closely matched by the IG model, however the BA model does not show the
rich-club phenomenon at all.
