Clustering algorithms for multi-level address hierarchies

Hierarchical addresses are fundamental to the scalability of Internet routing. The explosive of the Internet has strained the initial two-level hierarchy and led to the development of more flexible divisions between levels (CIDR) and larger addresses (IPv6). Equally, important are algorithms and protocols to systematically assign addresses with appropriate hierarchical structure to allow route aggregation. This paper describes and analyzes two algorithms for clustering network nodes into a multi-level address hierarchy. We evaluate the resulting address assignment with respect to routing table size, path length and concentration of traffic. We also explicitly recognize the need for "robustness" or "slack" the assignment to accommodate future changes in topology. Our evaluation includes both single- and multi-domain topologies.