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Unformatted text preview: eceived within the specified time).
Whenever the Timer expires (i.e., a CLCW positively acknowledging that the last
Transfer Frame on the Sent_Queue has not been received within the specified time),
FOP-1 checks whether the value of the Transmission_Count has reached the value of
the Transmission_Limit. If it has not, FOP-1 shall increment the count and initiate
retransmission of the Transfer Frames on the Sent_Queue. If it has, FOP-1 shall CCSDS 232.1-B-2 Page 5-8 September 2010 RECOMMENDED STANDARD FOR COMMUNICATIONS OPERATION PROCEDURE-1 select one of two types of possible actions depending on the value of the
1) if TT = 0, FOP-1 generates an ‘Alert’ notification;
2) if TT = 1, FOP-1 suspends the AD Service, which may be resumed later if so
required (see definitions of Suspend_State variable (SS) in 5.1.11 and ‘Resume
AD Service’ Directive in 4.1).
There is only one sort of event which may cause FOP-1 to initiate retransmission of a TypeBC Transfer Frame:
a) The Timer expires (a CLCW positively acknowledging the Type-BC Transfer Frame
has not been received within the specified time).
b) Whenever the Timer expires, FOP-1 checks whether the value of the
Transmission_Count has reached the value of the Transmission_Limit. If it has not,
FOP-1 shall increments the count and initiate retransmission of the Type-BC Transfer
Frame. If it has, FOP-1 shall generate an ‘Alert’ Indication.
5.1.11 SUSPEND_STATE (SS)
The Suspend_State variable is referred to as ‘SS’. It may take one of five values, from ‘0’ to
‘4’. It records the state that FOP-1 was in when the AD Service was suspended (as described
in subsection 0). This is the state to which FOP-1 will return should the AD Service be
resumed. If SS = 0, the AD Service is deemed not suspended.
5.1.12 FOP_SLIDING_WINDOW_WIDTH (K)
The value to which the FOP_Sliding_Window_Width is set is referred to as ‘K’ and may be
changed using the ‘Set FOP_Sliding_Window_Width’ Directive.
The FOP Sliding Window is a mechanism which limits th...
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This document was uploaded on 03/06/2014.
- Spring '14