We describe Fair Layered Increase/Decrease with Dynamic Layering (FLID-DL), a new multi-rate congestion control algorithm for layered multicast sessions. FLID-DL generalizes the receiver-driven layered congestion (RLC) control protocol introduced by Vicisano, Rizzo, and Crowcroft, ameliorating the problems associated with large IGMP leave latencies and abrupt rate increases. Like RLC, FLID-DL is a scalable, receiver-driven congestion control mechanism in which receivers add layers at sender-initiated synchronization points and leave layers when they experience congestion. FLID-DL congestion control coexists with TCP flows as well as other FLID-DL sessions and supports general rates on the different multicast layers. We demonstrate via simulations that our congestion control scheme exhibits better fairness properties and provides better throughput than previous methods.
A key contribution that enables FLID-DL and may be useful elsewhere is Dynamic Layering (DL), which mitigates the negative impact of long IGMP leave latencies and eliminates the need for probe intervals present in RLC. We use DL to respond to congestion much faster than IGMP leave operations, which have proven to be a bottleneck for prior work.
To appear in NGC 2000.