Directory Proxy Server divides directory information into multiple servers but does not require that the hierarchy of the data be altered. An important aspect of data distribution is the ability break up the data set in a logical manner. However, distribution logic that works well for one client application might not work as well for another client application.
For this reason, Directory Proxy Server enables you to specify how data is distributed and how directory requests should be routed. For example, LDAP operations can be routed to different directory servers based on the directory information tree (DIT) hierarchy. The operations can also be routed based on operation type or on a custom distribution algorithm.
Directory Proxy Server effectively hides the distribution details from the client application. From the clients' standpoint, a single directory addresses their directory queries. Client requests are distributed according to a particular distribution method. Different routing strategies can be associated with different portions of the DIT, as explained in the following sections.
This strategy can be used to distribute directory entries based on the DIT structure. For example, entries in the subtree o=sales,dc=example,dc=com can be routed to Directory Server A, and entries in the subtree o=hr,dc=example,dc=com can be routed to Directory Server B.
In some cases, you might want to distribute entries across directory servers without using the DIT structure. Consider, for example, a service provider who stores entries that represent subscribers under ou=subscribers,dc=example,dc=com. As the number of subscribers grows, there might be a need to distribute them across servers based on the range of the subscriber ID. With a custom routing algorithm, subscriber entries with an ID in the range 1-10000 can be located in Directory Server A, and subscriber entries with an ID in the range 10001-infinity can be located in Directory Server B. If the data on server B grows too large, the distribution algorithm can be changed so that entries with an ID starting from 2000 can be located on a new server, Server C.
You can implement your own routing algorithm using the Directory Proxy Server DistributionAlgorithm interface.