Organizing Multicast Receivers Deterministically According to Packet-Loss Correlation

The ability to trace multicast paths is currently available in the Internet by means of IGMP MTRACE packets. We introduce Tracer, the first protocol that organizes the receivers of a multicast group deterministically while maintaining exact packet-loss correlation for local error recovery, and without requiring any changes to existing multicast routing protocols. Tracer uses MTRACE packets in IGMP to allow a receiver host to obtain its path to the source of a multicast group. Receivers use the multicast path information to determine how to achieve local error recovery and effective congestion control. We compare the tracing approach with prior mechanisms that attempt local recovery. Results of measurements carried out over the CAIRN illustrate the fact that tracing multicast paths is an effective tool to organize receivers based on their packet-loss correlation.