Selective broadcast data distribution systems

This paper describes a two tier architecture for high speed data distribution. The architecture consists of a database interface network which distributes information from a central database to a number of servers, and a user interface network which distributes information from the servers to the user terminals. The database interface network uses the selective broadcast technique to distribute data on a high speed channel. Data requested by users are filtered out by the servers and sent to the user terminals through the user interface network. The user interface network can be any conventional local area network for connecting the servers and the user terminals. A very tight upper bound on the mean response time of the system for uniform request distribution is first derived. This is followed by an approximate analysis for general request distributions. Simulation results and design examples showed that selective broadcast technique can provide an order of magnitude smaller response time under normal traffic conditions when compared to the nonselective broadcast technique such as the Datacycle system.