> Matthieu Latapy, Clémence Magnien and Frédéric Ouédraogo
traceroute is a tool that gives the internet path followed by your packets towards a given destination, under the form of a series of IP addresses. Consider a given set of destinations, and let us call the result of a traceroute towards each of these destinations a round of measurement. One may quess that, after a reasonable number of such rounds, no or very few new IP addresses will be discovered by new rounds. One would basically have seen all that can be seen between the computer running traceroute and these destinations.
The plot above shows that this does not happen. We sampled 3000 random IP addresses which answered to ICMP Echo Request and ran a round of measurement every 15 minutes (approximately 100 times a day). We report the number of distinct IP addresses seen since the beginning (in black) and the number of IP addresses which were present at all rounds (in blue) as a function of the number of rounds of measurements we ran.
Surprisingly enough, the number of observed IP addresses still grows after 2100 rounds (3 weeks of continuous measurement). Moreover this growth is not neglectible: in the last 100 rounds, the number of observed IP addresses increases by 2.6 %. Likewise, the number of stable addresses continuously decreases.
One may wonder if this is due to dynamic addresses in our destination set; to check this, we kept only destinations which were present during 90% of the rounds and were always observed immediately after the same IP address. We obtained similar plots.One may then guess that the observed growth is due to routers sending wrong (random?) addresses. However, this would lead to special structures in the graph, which we did not observe. It actually seems that the observed growth is due to the growth of the internet itself.