A previous post, on “Barabási – Albert preferential attachment and the Internet“, gave a plot of the Internet, as a sparsity map of its regular adjacency matrix, with the axes ordered by each ASes eigencentrality:
Each connection in the BGP AS graph is represented as a dot, connecting the AS on the one axis to the AS on the other. As the BGP AS graph is undirected, the plot ends up symmetric. The top-right corner of this plot shows that the most highly-ranked ASes are very densely interconnected. The distinct outline probably is indicative (characteristic?) of a tree-like hierarchy in the data.
Who are these top-ranked ASes though? Are they large, well-known telecommunications companies? The answer might be surprising.