MERLIN: MEasure the router level of the INternet

In this paper, we present a new router-level Internet mapping tool called MERLIN. MERLIN takes advantage of mrinfo, a multicast management tool that collects all IPv4 multicast enabled interfaces of a router and all its multicast links towards its neighbors. Our new probing tool fixes mrinfo technical limitations and eases the deployment of multicast probing campaign. We deploy and evaluate the performance of MERLIN at large scale. We investigate the completeness of MERLIN by providing a lower bound on the proportion of information that it may miss. We also demonstrate that the use of several vantage points is crucial to circumvent IGMP filtering in order to increase the amount of collected routers. MERLIN is a valuable tool for collecting the router-level Internet topology.