After you install the Replication Agent software, you must create one instance of the Replication Agent for each primary database that you want to replicate transactions from.
Each Replication Agent instance is an independent process, with its own instance directories to contain its configuration file, system log files, and script files. In addition, each Replication Agent instance creates some tables and stored procedures in the primary database. Replication Agent for Oracle also creates objects in the Replication Agent System Database (RASD). A Replication Agent instance manages its own connections to the primary data server, primary Replication Server, and RSSD.
You can create and run more than one Replication Agent instance on a single host machine, but each instance must have a unique name and a unique port number.