Supporting the Need for Inter-Domain Multicast Reachability
Kamil Saraç, Kevin C. Almeroth · 2000
Internet multicast is transitioning from the flat, virtual topology known as the Multicast Backbone (MBone) to a hierarchical, globally deployed service. This transition introduces a number of important management issues. In particular, it is believed that the success of multicast on a large scale partly depends on the availability of good management tools. In this paper, we address the specific management problem of monitoring multicast reachability. We first define the semantics of multicast reachability and how they differ from unicast reachability. We then motivate the importance of being able to monitor multicast reachability. Based on this discussion, we have developed a system, called sdr-monitor, to monitor reachability on a global scale. Using sdr-monitor we have collected almost a year of reachability data. In analyzing the data, we first process it to remove artifacts caused by using sdr. We then analyze the data to calculate a percentage of reachability in the multicast infrastructure. While we find that the current infrastructure is significantly unstable, the main reasons are likely the newness of inter-domain multicast and the challenge of developing "in-the-network" services on top of IP.