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Unformatted text preview: ype (TT);
o) Suspend_State (SS).
These variables are described in detail in the following subsections. CCSDS 232.1-B-2 Page 5-1 September 2010 RECOMMENDED STANDARD FOR COMMUNICATIONS OPERATION PROCEDURE-1 5.1.2 STATE The state of FOP-1 may be one of the following:
a) Active (S1);
b) Retransmit without Wait (S2);
c) Retransmit with Wait (S3);
d) Initializing without BC Frame (S4);
e) Initializing with BC Frame (S5);
f) Initial (S6).
This variable represents the state of FOP-1 for the specific Virtual Channel. Each value of
the State variable shall correspond to a column in the FOP-1 State Table (table 5-1).
‘Active’ State (S1) is the normal state of the state machine when there are no recent errors on
the link and no incidents have occurred leading to flow control problems.
The state machine is in the ‘Retransmit without Wait’ State (S2) while the ‘Retransmit’ Flag
is ‘on’ in the CLCW of the Virtual Channel but no other exceptional circumstances prevail.
The state machine is in the ‘Retransmit with Wait’ State (S3) while the ‘Wait’ Flag is ‘on’ in
the CLCW of the Virtual Channel. (Some Transfer Frames must always be retransmitted
when the ‘Wait’ Flag is reset, since the ‘Wait’ Flag is set only when at least one Transfer
Frame has been discarded.) In this state the ‘Retransmit’ Flag will also be set (as a
consequence of the fact that Transfer Frames have been lost).
The state machine is in the ‘Initializing without BC Frame’ State (S4) after receiving an
‘Initiate AD Service (with CLCW check)’ Directive while in the ‘Initial’ State. A successful
CLCW check will result in a transition to S1.
The state machine is in the ‘Initializing with BC Frame’ State (S5) after receiving an ‘Initiate
AD Service (with Unlock)’ Directive or ‘Initiate AD Service (with Set V(R))’ Directive
while in the ‘Initial’ State with BC_Out_Flag = Ready. A successful transmission of the
Type-BC Transfer Frame and a subsequent ‘clean’ CLCW status will result in a transition to
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This document was uploaded on 03/06/2014.
- Spring '14