The Maximum Protection mode is referred to as the Guaranteed Zero Data Loss configuration. A primary database operating on the Maximum Protection mode doesn't provide an acknowledgment to the users that the commit is completed until transactions are successfully transferred to at least one standby destination. This setup requires the SYNC redo transport service using the LGWR attribute and guarantees that no data will be lost on the standby database in case of a primary database failure.
Of course, guaranteeing zero data loss comes at a cost. Because the primary database will always wait for an acknowledgment from standby destinations to continue its operation, there will be performance implications on the primary database. However, with 11g, the performance effect of using the SYNC redo transport service is less than the earlier releases. In the previous releases, the primary database doesn't send a redo to the standby database before completing the write to online...