The Rich-Club Phenomenon In The Internet Topology

TL;DR

This paper demonstrates that the Internet's Autonomous System topology exhibits a rich-club phenomenon where highly connected nodes are well interconnected, providing insights into network structure and modeling.

Contribution

It identifies and measures the rich-club phenomenon in Internet topology without heuristics, offering a new criterion for network model evaluation.

Findings

Rich nodes form a well-connected core in AS topology.

The rich-club phenomenon differentiates power law topologies.

Comparison with models shows differences in rich-club connectivity.

Abstract

We show that the Internet topology at the Autonomous System (AS) level has a rich--club phenomenon. The rich nodes, which are a small number of nodes with large numbers of links, are very well connected to each other. The rich--club is a core tier that we measured using the rich--club connectivity and the node--node link distribution. We obtained this core tier without any heuristic assumption between the ASes. The rich--club phenomenon is a simple qualitative way to differentiate between power law topologies and provides a criterion for new network models. To show this, we compared the measured rich--club of the AS graph with networks obtained using the Barab\'asi--Albert (BA) scale--free network model, the Fitness BA model and the Inet--3.0 model.