An Optimized Multicast-based Data Dissemination Middleware: A Demonstration

A major problem on the Internet is the scalable dissemination of information. This problem is particularly acute exactly at the time when the scalability of data delivery is most important, e.g., election results on the night of the 2000 United States presidential election, and news during 9/11/2001. The current unicast pull framework simply does not scale up to these types of workloads. One proposed solution to this scalability problem is to use multicast communication. However, allowing multicast communication introduces many non-trivial data management problems, such as caching, consistency, and scheduling. We have been building a middleware that unifies and extends state-of-theart data management methods and algorithms into one software distribution. Its flexible and extensible architecture is built from individual components that can be selected or replaced depending on the underlying multicast transport mechanism or on the application needs. Particular care has gone into the design of the algorithms to optimize the userperceived level of service.