HP-UX Directory Server 8.1 deployment guide

Figure 6-5 Replication traffic in a multi-master environment
6.2.3 Cascading replication
In a cascading replication scenario, a hub supplier receives updates from a supplier server and
replays those updates on consumer servers. The hub supplier is a hybrid; it holds a read-only
replica, like a typical consumer server, and it also maintains a changelog like a typical supplier
server.
Hub suppliers forward master data as they receive it from the original suppliers. Similarly, when
a hub supplier receives an update request from a directory client, it refers the client to the supplier
server.
Cascading replication is useful if some of the network connections between various locations in
the organization are better than others. For example, Example Corp. keeps the master copy of
its directory data in Minneapolis, and the consumer servers in New York and Chicago. The
network connection between Minneapolis and New York is very good, but the connection between
Minneapolis and Chicago is poor. Since the network between New York and Chicago is fair,
Example administrators use cascading replication to move directory data from Minneapolis to
New York to Chicago.
6.2 Common replication scenarios 79