| 摘要 |
A first computer sends a sequence of messages to a second computer using remote write operations to directly store each message in a corresponding memory location in the second computer. The second computer retains information denoting the sequence numbers of the messages it receives and processes, and it acknowledges each received message with an asynchronous acknowledgment message. The first computer keeps track of which messages it has sent but for which it has not yet received an acknowledgment. Whenever the first computer determines that it has failed to receive a message acknowledgment from the second computer in a timely fashion, or it needs to reuse previously used message sequence numbers, the first computer undertakes remedial actions to resynchronize the first and second computers. The process begins by prompting the second computer to flush and process all the messages in its receive FIFO, and then comparing sequence number information recorded by the second computer with the sequence numbers of the outstanding, unacknowledged messages sent by the first computer. If the comparison indicates that any messages sent by the first computer were not received and processed by the second computer, those messages are re-transmitted. If necessary, during resynchronization the first computer will activate a different communication interface than the one previously used so as to establish a reliable connection to the second computer. After a success resynchronization, normal "send only" message operation resumes. At predefined times, the sequence number information retained by the second computer is cleared.
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