Sampling ISP Backbone Topologies.

Large computer networks are too large to emulate or actually reproduce in conventional lab environments. Graph generation/reduction techniques have been a valuable tool to solve this limitation. However, current techniques focus on local features (e.g. router out-degree, clustering coefficient, traffic difference between edges for building a hierarchy) that do not preserve router-level backbone geographical/hierarchical features or the end-to-end delay between any arbitrary points. This letter proposes a geographical-based reduction mechanism that enables emulation in lab settings while preserving the global features of typical backbone networks. The performance evaluation is based on six inferred ISP backbone maps.