What does ZAB mean in UNCLASSIFIED

ZooKeeper Atomic Broadcast (ZAB) is an asynchronous atomic broadcast protocol based on zookeeper that provides sequentially consistent atomic broadcast service for distributed systems.

ZAB is used by distributed applications to ensure consensus among nodes. It also establishes total order broadcast primitive which ensures reliable message ordering across nodes in a cluster.

ZAB works by having each node agree upon a sequence number before sending any data out to the network, thus ensuring that messages are sent out in the same order at each node in the cluster. This sequence number is incrementally increased so that no two messages have the same sequence number, thus guaranteeing total ordering.

ZAB is a robust, stable and fault tolerant system which makes it suitable for use in mission critical applications such as online banking or medical information systems. Additionally, it has low latency making it very fast and efficient when dealing with real-time tasks such as streaming media or transaction processing.

Yes, there are other alternatives such as Paxos and Raft protocols but they are not as reliable or efficient as ZAB due to their higher latency and overhead costs associated with implementing them across multiple nodes in a cluster.