| The large-scale behavior of routing in the Internet has gone virtually
without any formal study, the exceptions being Chinoy's analysis
of the dynamics of Internet routing information [Ch93], and recent
work, similar in spirit, by Labovitz, Malan and Jahanian [LMJ97].
We report on an analysis of 40,000 end-to-end route measurements
conducted using repeated "traceroutes" between 37 Internet sites.
We analyze the routing behavior for pathological conditions, routing
stability, and routing symmetry. For pathologies, we characterize
the prevalence of routing loops, erroneous routing, infrastructure
failures, and temporary outages. We find that the likelihood of
encountering a major routing pathology more than doubled between
the end of 1994 and the end of 1995, rising from 1.5% to 3.3%. For
routing stability, we define two separate types of stability,
"prevalence," meaning the overall likelihood that a particular route
is encountered, and "persistence," the likelihood that a route
remains ...
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