The core engine of iToM performs the following processing on the raw traceroute data:

Removing Incorrect Traces: This step primarily involves validating the traces. It also detects and removes routing loops.

Resolving Anonymous Routers: A  router that does not respond to a traceroute query is referred to as an anonymous router and is represented by a * in the traceroute output. Anonymous router resolution refers to the task of identifying the occurrences of *'s that belong to the same router in the underlying network. In this step, we use a novel technique from graph data mining field to build an efficient solution to the anonymous router resolution problem.

Resolving IP Aliases: The step involves the task of identifying IP addresses belonging to the same router in the collected data set. Here we use an alias resolution algorithm called Analytical and Probe-based Alias Resolver (APAR). Given a set of path traces, APAR utilizes the common IP address assignment scheme to infer IP aliases within the collected path traces.

Inferring Subnets: Utilizing a technique to infer the subnet relations among the routers in the resulting topology map, we identify IP addresses that are connected over the same connection medium. We believe that the successful inclusion of subnet relations among the routers will yield topology maps that are closer, at the network layer, to the sampled segments of the Internet in router level topology measurement studies.