The Store-and-Forward (SAF) service enables WebLogic Server to deliver messages reliably between applications that are distributed across WebLogic Server instances. If the destination is not available at the moment the messages are sent, either because of network problems or system failures, then the messages are saved on a local server instance, and are forwarded to the remote destination once it becomes available.
SAF agents are responsible for store-and-forwarding messages between local sending and remote receiving endpoints. A SAF agent can be configured to have only sending capabilities, receiving capabilities, or both. JMS SAF only requires a sending agent on the sending side for JMS messages. Whereas, WSRM SAF requires both a sending agent and a receiving agent.
For more information about JMS Unit-of-Order, see Using Message Unit-of-Order.