Multicast monitoring: Supporting a robust multicast service in the Internet

Multicast provides scalable mechanisms to reach hundreds or thousands of simultaneous receivers in the network. Within the last decade, there has been a significant effort in developing necessary protocols for multicast and integrating multicast into the Internet as a transparent service. During this time, it has been well recognized that the success of multicast highly depends on the availability of good monitoring and management systems. In this dissertation, we have focused on this aspect of the problem. We have identified the characteristics of multicast monitoring tasks and developed mechanisms and protocols to perform a set of critical monitoring tasks.; For any new service in the Internet, one of the first management tasks is to verify the availability of the service and maintain its robustness in the network. This task requires an ability to detect and isolate potential problems in the network. In the first part of our work, we have mainly focused on developing systems/protocols to detect the existence of potential multicast problems in the network. For multicast, problem detection requires monitoring multicast data transfer activity in the network. This monitoring is usually referred to as reachability monitoring. We have first developed an application-layer reachability monitoring system called sdr-monitor . This system has been very useful to the multicast community in detecting potential problems in the network. Next, we have used this experience to develop a more systematic approach (a generic architecture) for multicast reachability monitoring systems. And, finally, we have used this architecture to evaluate and improve an already existing protocol, the Multicast Reachability Monitor (MRM) protocol.; In the second part of our work, we focused on problem isolation for multicast. Since the multicast service depends on forwarding trees that are created dynamically by routers in the network, problem isolation usually requires collecting multicast tree topologies from the network. In our work, we have developed a mechanism, called tracetree, for discovering multicast tree topologies from the network. Tracetree uses the existing multicast forwarding state for topology discovery. Compared to alternative approaches, tracetree is more effective, more scalable and more efficient in discovering tree topologies in the network.