With this transfer notification signal fop 1 signals

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Unformatted text preview: RATION PROCEDURE-1 4.4.2 TRANSFER NOTIFICATIONS FOR TYPE-A (OR AD) SERVICE After each ‘Request to Transfer FDU’ from the Higher Procedures (see 3.2.2.3.2), either immediately or after a delay, FOP-1 shall return to the Higher Procedures either an ‘Accept Response to Request to Transfer FDU’ or a ‘Reject Response to Request to Transfer FDU’ referring to the Request. With this transfer notification signal, FOP-1 signals its acceptance or rejection of the Request. If a ‘Reject Response to Request to Transfer FDU’ is returned, then no other transfer notification signals shall be returned for the Request. However, if FOP-1 is unable to transmit the FDU immediately (for example, because the receiving end has indicated it cannot immediately accept any more data), then FOP-1 will delay signaling to the Higher Procedures its acceptance of the FDU, even though it places the FDU in its Wait_Queue. The Higher Procedures may not issue another ‘Request to Transfer FDU’ until the current one has been accepted or rejected. Whenever FOP-1 has transfer capacity after a period when no extra capacity was available, it checks to see if an FDU is in the Wait_Queue. If so, FOP-1 accepts the FDU, which is then deemed to be under control of FOP-1, and returns an ‘Accept Response to Request to Transfer FDU’. After each ‘Accept Response to Request to Transfer FDU’, but asynchronously from the Response, FOP-1 shall signal to the Higher Procedures either a ‘Positive Confirm Response to Request to Transfer FDU’ or a ‘Negative Confirm Response to Request to Transfer FDU’ referring to the Request. Because there may be a number of FDUs which have been accepted, but not confirmed, the Higher Procedures and FOP-1 need to share a common system of request identifiers for use when referring to a particular Request (and, therefore, to a particular FDU). The ‘Positive Confirm Response to Request to Transfer FDU’ shall notify the Higher Procedures that the FDU was received by the receiving end and acknowledged by a CLCW. If CO...
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This document was uploaded on 03/06/2014.

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