Archipelago Monitor Statistics

CCDF of IP path lengths for responding destinations

• percentile	10th	25th	50th	75th	90th	Max
  IP path length	12	15	17	20	23	35

  

Use the following link to download the data used to render this graph in ASCII, comma-separated values format here: (CSV output)

Description

This graph shows the complementary cumulative distribution function (CCDF) of path lengths (number of hops) to a destination that responds to probing.

Motivation

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 Internet.

Background

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.

Analysis

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 local network.