CCDF of IP path lengths for responding destinations
|IP path length
Use the following link to download the data used to render this graph in ASCII, comma-separated values format here: (CSV output
This graph shows the complementary cumulative distribution function (CCDF)
of path lengths (number of hops) to a destination that responds to probing.
By showing the distribution of path lengths to all responding destinations,
we can get a sense of how closely connected a monitor is to the 'core' of
The complementary cumulative distribution function shows the fraction of
collected data points that are greater than a given value. This is
backwards from how percentiles are given, as those show the percentage
lower than a given value. On this graph, you would find the 80th
percentile at the 0.2 Y value.
The path length is defined as the number of IP hops required to reach the
destination from the Ark monitor. This includes any routing loops that
occur during the probing. These values are only used when a response has
been received from the destination. In other words, incomplete paths are
ignored for the purposes of determining path length.
The shape of the path length CCDF typically doesn't very much from monitor
to monitor, as the distribution of path lengths to randomly selected set of
destinations is mostly determined by the 'core' of the Internet. Routing
loops or large internal networks (on the monitor's side) can shift the
path length values higher, but the range doesn't vary dramatically. If
a monitor's path length CCDF looks suddenly very different from other
monitors', it's quite possible that there's a configuration problem in the