In the left side of this figure are four disk drives with one disk labeled as the "Hub" and the other three disks labeled as "Satellites." The Hub is in the center of the figure with bidirectional arrows connecting the hub to each of the three satellites. This indicates that Oracle Streams supports the capture of data changes at the primary database or downstream at a replica database, enabling you to build this hub-and-spoke network configuration that supports three replica databases.

On the right side of the figure are two disk drives that are being maintained by Oracle Data Guard to provide additional protection for the hub and one of the satellites. This is indicated by two arrows in the center of the illustration, with "Oracle Oracle Data Guard" in the center of each arrow that points to the site with the standby hub and standby satellite.