Application layer reachability monitoring for IP multicast

In this paper, we present an application layer mechanism to monitor multicast reachability. First, we justify the need for reachability monitoring systems. Then, we present our monitoring system called sdr-monitor. Sdr-monitor leverages an existing application and provides close to real-time reachability monitoring for the multicast infrastructure. It is the first system that is developed and deployed for monitoring multicast reachability. We present the architecture of the system and then discuss its operation. Finally, we include our evaluations on a data set that we collected using this system. With this analysis, we present long term reachability characteristics of multicast infrastructure during a four year monitoring period between 1999 and 2003 and discuss potential causes for reachability problems.