There are three different replication techniques available. They are snapshot replication, merge replication and transactional replication.
Snapshot replication is a single unidirectional push of data. When updated data is fed from the publisher to the subscribers, all of the data is sent each time.
Merge replication is a bidirectional replication that transmits data either in real time, or on a schedule. Merge replication is the only bidirectional replication technique available.
Transactional replication is unidirectional from the publisher to the subscribers. Data can be sent on a schedule or in real time. As data is transmitted to the subscriber, all data changes are processed in the order they were made on the publisher.
