The Duplication Manager process in coordination with the Arbiter process runs on the servers to control data shadowing between the servers.

At the physical and data-link layers, an Ethernet-based duplication link provides a TCP communication path between the Duplication Manager of each server to control data shadowing. This TCP/IP link provides the actual data shadowing for software duplication. For hardware duplication, there is an additional fiber optic link between the duplication memory boards that provides the data shadowing.