Unformatted text preview: 4.1 DIRECTIVE REQUEST To control the operations of COP-1, the authorized user at the sending end can invoke a
Directive by passing the DIRECTIVE.request primitive to the protocol entity (see
reference ). The type of Directive shall be indicated by the parameter Directive Type of
the DIRECTIVE.request primitive. If the Directive has a parameter, it shall be carried by the
parameter Directive Qualifier.
A DIRECTIVE.request primitive issued by the user shall be translated by the Higher
Procedures to a directive request signal (see 18.104.22.168.2), which is then delivered to FOP-1.
The Directive Types of the DIRECTIVE.request primitive defined here shall also be used as
the Directive Types of the directive request signal given to FOP-1.
In this subsection, the Directive Types used by COP-1 are defined. The Directive Types are
classified into four categories:
a) four ‘Initiate AD Service’ Directives;
b) one ‘Terminate AD Service’ Directive;
c) one ‘Resume AD Service’ Directive;
d) five ‘FOP-1 Setup’ Directives.
Any other Directive will be rejected and reported as an invalid Directive.
Table 4-1 shows the Directive Types and Directive Qualifiers defined for COP-1. For other
parameters used by the DIRECTIVE.request primitive, see reference .
These twelve Directives correspond to Events E23 through E40 in the FOP-1 State Table
1 The FOP-1 Directives include the ‘Terminate AD Service’ Directive. In the ‘Initial’
State (S6) this Directive is not effective in the case that the Suspend_State (SS) is not
equal to zero. When SS is not equal to zero, it means that the FOP-1 AD Service has
been suspended. In this case, the Directive is Accepted and Confirmed but the AD
Service remains suspended (i.e., Suspend_State remains different from zero, the
queues are not purged, etc.). To terminate a suspended AD Service, the service may
first be resumed with a ‘Resume AD Service’ Directive (and then a subsequent CCSDS 232.1-B-2 Page 4-1 September 2010 RECOMMENDED STANDARD FOR COMMUNI...
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- Space Exploration, ........., European Space Agency, CCSDS