Cascading Replication - Netscape DIRECTORY SERVER 6.2 - DEPLOYMENT Deployment Manual

Common Replication Scenarios
Figure 6-5 Replication Traffic in a Multi-Master Environment

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 maintains
a change log like a typical supplier server.
Hub suppliers pass the master data on as they received them from the original
masters. For the same reason, when a hub supplier receives an update request
from a directory client, it refers the client to the master server.
Cascading replication is useful, for example, if some network connections between
various locations in your organization are better than others. For example, suppose
the master copy of your directory data is in Minneapolis, and you have consumer
servers in Saint Cloud as well as Duluth. Suppose, too, that your network
connection between Minneapolis and Saint Cloud is very good, but your network
connection between Minneapolis and Duluth is of poor quality. Then, if your
network between Saint Cloud and Duluth is of acceptable quality, you can use
cascaded replication to move directory data from Minneapolis to Saint Cloud to
Duluth.
Chapter 6 Designing the Replication Process 117