| 摘要 |
PURPOSE:To prevent a throughput or efficiency in a transmission line from being lowered, by resending only a frame in which an error is generated normally, and resending all the frames after the frame in which the error is generated, when the number of erroneous frames exceed a regulated value continuously. CONSTITUTION:In a normal operation, only the erroneous frame is resent, and also at the same time, a system is regulated by a Selective Repeat ARQ possible to perform plural number of resending requests. And when the number of continuous erroneous frames exceed the regulated value, all of the frames after the frame in which the error is generated, are resent by logic link unit sharing a data link. The system is switched to a Go-Back-N ARQ system, then a resending is performed. In this way, data to be resent is the one that is transmitted by logic links 10-12 sharing a channel, and for example, when the error is generated in the logic link 10 which transmits the data belonging to an application program 7, only the data of the logic link 10 is resent, therefore, it is not necessary to resend the data transmitted by other logic links.
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