Subnet level network topology mapping

Internet topology at the network layer consists of routers and subnets, i.e., point-to-point or multi-access connections. Network measurement studies have focused on router level maps and derived characteristics of routers such as mean degree, degree distribution, clustering coefficient and betweenness. Considering the fact that subnets are also important building blocks of the Internet topology, this paper introduces a complementary view of network topologies named subnet level maps. Subnet level network topology maps represent subnets as vertices and depict routers as links connecting the vertices/subnets. Additionally, we introduce a tool, called exploreNET, for subnet discovery. Although ExploreNET is based on the same principals as our recent work traceNET [21], it differs from traceNET in its utilization in various domains. Particularly, it allows us discover the underlying subnet level topology map of a network rather than the map dictated by routing dynamics. Finally, we present an evaluation of exploreNET by using it to discover and analyze various subnet characteristics including degree distribution, capacity distribution and utilization for six geographically disperse public Internet Service Providers (ISPs).