In this paper we propose a multicast-on-large-demand (MOLD) approach to the flash crowd problem. A MOLD Web server may dynamically open a multicast channel for resources when detecting a very high demand for them, and it reverts back to the normal unicast mode when the flash crowd subsides. A number of mechanisms necessary for realizing the MOLD system are thoroughly discussed. We have implemented the MOLD system in Java and evaluated the performance in a test-bed. Categories and Subject Descriptors C.2 [Computer Systems Organization]: ComputerCommunication Networks; I.6 [Computing Methodologies]: Simulation and Modeling General Terms Measurement, Performance, Design Keywords Flash Crowds, Hypertext Transfer Protocol, Multicast
Rocky K. C. Chang