Understanding federated repositories

The Sametime prerequisites require you to identify at least one LDAP server for use with the server components. But in some cases, you may want multiple LDAP servers to be used for authentication. In the federated repository option, several different LDAP directories, each containing separate lists of users, would behave as a single directory from a Sametime perspective. Sametime would authenticate all users regardless of which directory they are in and give them the same status. It is critical that users do not appear in more than one directory with the same identity, as this could cause authentication issues.

It is important to note that this is not the same as having multiple LDAP servers representing the same directory and providing redundancy for each other. You cannot configure redundancy with multiple LDAP servers within Sametime, as Sametime expects each LDAP server to be unique. You would have to use a network load balancer and a single DNS hostname...