The message-based synchronization model is inherently asynchronous. The interaction, however, can either be synchronous, or asynchronous for messaging-based synchronization. During transmission, the client and server submit pending operations and obtain the latest changes.
Inherently asynchronous, data changes from the server to client are automatically sent and applied to client’s local data store, and, similarly, operation executions from the client to server are sent in the background without requiring explicit action from device application. The developer can choose to keep transactions from being uploaded to the server by manipulating state of the submission (as pending).
Message-based services support a mobile application class that consumes message events for data and notifications or actions, and generates events to propagate changes in an always-on network availability scenario.
Message-based synchronization works well in situations that require functionality to send updates to the client intermittently with small data payload. As with replication-based synchronization, message-based synchronization can also store large amounts of data on the device, and data exchange may be more transient, mobile workflow-related, and occurs continuously throughout the life cycle of the application. This paradigm is supported on Windows, Windows Mobile, and iOS device platforms.