US Patent 8675672 Hierarchical cluster tree overlay network

A Hierarchical Cluster Tree (HCT) overlay network reflects underlying physical network topology including inter-node distances (e.g., hop count), and an HCT structure groups nodes based on distance measurements. Local area networks (LANs) are basic building blocks. The network includes first and second level-1 clusters of LANs, each LAN including computerized data processing and/or storage nodes. A distance between LANs in the level-1 clusters is less than or equal to a predefined level-1 maximum distance. The LANs of the first and second level-1 clusters form a level-2 cluster of LANs in which a distance between cluster medoid nodes of the level-1 clusters is less than or equal to a predefined level-2 maximum distance greater than the level-1 maximum distance. Clustering can be extended to higher levels having successively greater maximum distances.