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Unformatted text preview: 232.1-B-2 Page 4-4 September 2010 RECOMMENDED STANDARD FOR COMMUNICATIONS OPERATION PROCEDURE-1 Table 4-4 lists the reasons for the ‘Alert’ notification. The Reason Code is carried by the
parameter Notification Qualifier of the Async_Notify.indication primitive.
NOTE – In addition to the Reason Code, an implementation may choose to include
parameters giving the FOP Event number that caused the ‘Alert’ and the FOP
State at the time of the Event. The additional information may assist the higher
Table 4-4: Reasons for the ‘Alert’ Notification Reason Reason
Code Allowed number of transmissions exhausted for a Type-AD Transfer Limit or T1
• In case a CLCW arrives which negatively acknowledges a frame
when Transmission_Limit is set to 1, FOP-1 generates an
‘Alert[limit]’. • In case the Timer expires and the value of the Transmission_Count
has reached the value of the Transmission_Limit, FOP-1 generates
an ‘Alert[T1]’. (Note: This ‘Alert’ Indication cannot occur if the
Timeout_Type variable is set to ‘1’.) Allowed number of transmissions exhausted for a Type-BC Transfer T1
Frame derived from a Directive (e.g., ‘Initiate AD Service’ Directive with
‘Unlock’ or with ‘Set V(R)’).
Lockout detected. Lockout CLCW with ‘Retransmit’ Flag = 0 and N(R) = NN(R) has arrived, when Synch
last CLCW showed ‘Retransmit’ Flag = 1.
All Transfer Frames sent are acknowledged but ‘Retransmit’ Flag = 1. Synch An attempt to acknowledge Transfer Frames is made during the Synch
initializing phase corresponding to State (S4).
CLCW with invalid N(R) has arrived. NN(R) CLCW with ‘Wait’ Flag = 1 and ‘Retransmit’ Flag = 0 has arrived. CLCW CLCW with invalid pattern of bits has arrived. CLCW FOP-1 and Lower Procedures are out of synchronization (Lower LLIF (Lower
Procedures rejects Transfer Frame even though appropriate ‘Out’ Flag Layer
is set to ‘Ready’).
A ‘Terminate AD Service’ Directive has arrived CCSDS 232.1-B-2 Page 4-5 Term September 2010 RECOMM...
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