The data change in the directory server must be propagated to OpenSSO Enterprise in a timely manner to ensure that OpenSSO Enterprise represents the correct data. The data in OpenSSO Enterprise is updated two ways. One way is by receiving notifications from the directory servers, and the other way is by polling the directory servers. For notification, directory servers typically provide persistent search notifications which OpenSSO Enterprise subscribes to. For polling, OpenSSO Enterprise provides configurable parameters to specify the intervals. OpenSSO Enterprise supports persistent search notifications with Sun Directory Server, Microsoft Active Directory, and IBM Tivoli Directory.