Database Change Protocol (DCP) is a fundamental replication protocol used in Couchbase Server 3.0, offering enhanced availability, performance, and scalability across geo-distributed data centers. DCP supports critical database functions such as protecting data from failures, maintaining fresh indexes through rapid data replication, and ensuring consistency and high performance through its memory-based streaming capabilities. It utilizes key components like vbucket UUIDs, sequence numbers, and failover logs to provide ordered, restartable, and consistent data replication. This framework allows for significant improvements in operations like incremental backups, low-latency view queries, delta recovery for faster node rebalancing, and durability guarantees through the "ReplicateTo" method. DCP also strengthens cross data center replication (XDCR) by minimizing data loss during regional disasters and efficiently recovering from network issues. Overall, DCP underpins over 200 features in Couchbase Server 3.0, driving its robust data handling and recovery capabilities.