Oracle Unified Directory replication model relies on 2 logical components, Directory Servers and Replication Servers.
Directory Servers contain user data, pushes changes to replication changed and get updates from replication servers.
Replication Server stores replication changes, they receive changes to directory servers and forward them to the rest of the topology.
By default, you don't need to care about Replication Servers. Replication Servers and internal components managed automatically: a Replication Server is autimatically configured in each OUD DIrectory Server process when replication is configured.
OUD Replication Server and Directory Servers are NOT equivalent to DSEE Suppliers and Consumers. By default, every replicated OUD is a Read-Write Supplier/Master.
When do you need to know about replication servers?
- Primarily, when full network connectivity cannot be guarantied across every instance as every Replication Server must be able to communicate to each other.
- Optionally, Replication Servers and DIrectory Servers can be separated to optimize resource usage in large OUD topologies (10's of instances)
- To enable external changelog service on a standalone OUD instance (for instance in a test environment) as a Replication Server is required is such case.