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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 18.104.22.168.2), 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
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.
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This document was uploaded on 03/06/2014.
- Spring '14