Topology 1: centralized tiered historian topology on a slow/intermittent network

This topology consists of ten tier-1 historians performing simple and summary replication of the same tags independently to two tier-2 historians. This topology is targeted to reflect the requirements of geographically distributed SCADA applications operating on slow and intermittent networks.

The 400 Kbps data transfer limit reflects a typical data transfer speed between remote locations over the Internet. The data transfer from each tier-1 historian to a tier-2 historian is assumed to be through a dedicated 400 Kbps connection; multiple tier-1 historians do not share the same 400 Kbps connection. It is assumed that the 400 Kbps is a bandwidth that can be fully used.