We have a configuration like this: C1-B1-------B2-C2 and persistent queues enabled. We have also tried enabling the exclusive consumer feature. First client C1 starts to send messages to queue, and C2 reads the messages from queue. Then I remove the network plug on broker B1 severing the connection between the brokers. When I reconnect the cable all messages that were produced while the connection was lost get delivered, but their ordering is not FIFO. Some messages get delivered in wrong sequence, perhaps they are being lost and then resend?