Study of Internet autonomous system interconnectivity from BGP routing tables

Abstract

Recently, several authors have proposed models based on power-laws to characterize Internet topologies . Most of these works use the BGP (Border Gateway Protocol) tables published by Oregon Route Views. The adjacency matrix containing AS (autonomous system) connectivity is built from a BGP table. Having access to BGP routing tables from several geographical sites gives a broader vision of ASs connectivity, since several ASs and links may be hidden for an AS due to routing processes policies, while they may be visible to other ASs. We compare BGP tables of different sizes and enrich the adjacency matrix with the union of them. This comparison is based on the AS degree connectivity , clustering coefficient and path length. Our initial results, published in [Proceedings of HPSR2003, Torino, Italy, June 2003], show an increment of 16% in the number of links and 0.7% in the number of ASs and show that a medium-size AS can get a vision similar to a repository such as Route Views. Most of the recent works analyze whether power-law distributions, also called scale-free models, arise on Internet topologies for the whole AS-level graph. However, few ones study whether the AS connectivity of the Internet core follows a power-law distribution. Here we use well-known heuristics to identify AS peeringship and split the Internet core from small regional ISPs and end customers. We will see that the Internet core does not fit a power-law well.