Therefore all arithmetic in the fop concerning the

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Unformatted text preview: e number of Transfer Frames which can be transmitted ahead of the last acknowledged Transfer Frame, i.e., before a CLCW report is received which updates the status of acknowledged Transfer Frames. This is done to prevent sending a new Transfer Frame with the same sequence number as a rejected Transfer Frame. The value ‘K’ shall be set to a value between the following limits: 1 ≤ K ≤ PW and K < 256 where ‘PW’ is the FARM_Positive_Window_Width as defined in subsection 6.1.8, ‘FARM Sliding Window Variables’. CCSDS 232.1-B-2 Page 5-9 September 2010 RECOMMENDED STANDARD FOR COMMUNICATIONS OPERATION PROCEDURE-1 5.2 FOP-1 ACTIONS 5.2.1 GENERAL This section defines the actions used in the FOP-1 State Table (table 5-1). Some of the actions defined here are used in the definition of other actions. NOTE – It should be noted that the COP-1 Frame Sequence Number is an 8-bit field. Therefore, all arithmetic in the FOP concerning the related fields V(S), N(R) and NN(R) should be performed modulo 256. In particular, this should be taken into account when reading the event conditions contained in the FOP-1 State Tables. 5.2.2 ‘PURGING THE SENT_QUEUE’ This action includes: clearing the Sent_Queue by generating a ‘Negative Confirm Response to Request to Transfer FDU’ for each Transfer Frame on the queue and deleting the Transfer Frame. NOTES 1 Purging the Sent_Queue occurs as part of the termination or (re)initialization (see Note 2) of an AD Service. 2 Purging is needed when the AD Service is (re)initiated because the FOP may have reached S6 via a Suspend Indication. 5.2.3 ‘PURGING THE WAIT_QUEUE’ This action includes clearing the Wait_Queue and generating a ‘Reject Response to Request to Transfer FDU’ for the queued FDU. 5.2.4 ‘TRANSMIT TYPE-AD FRAME’ This action includes all the functions necessary to prepare a Type-AD Transfer Frame for transmission. In particular it includes: a) inserting the current value of V(S) into the N(S) field of the Transfer Frame Primary Header and then incrementing V(S); b) adding the master co...
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