[Css-csts] EXECUTE-DIRECTIVE Possible redefinitions

[Ray, Timothy J. (GSFC-5830)]

Dear Yves,

I like option #1 because I can understand what is needed.

Do you think it might make sense to modify our AbstractType to add a third choice as follows?  I'm thinking that this may not be the only situation in which the 'user' of AbstractType will want the option of 'unused'.

AbstractType                        ::=        CHOICE
{                    unused                                                             NULL
,                     opaqueString                OCTET STRING
,        extendedData                EMBEDDED PDV
}

Or, create two classes of AbstractType as follows:

MandatoryAbstractType                        ::=        CHOICE
{
                     opaqueString                OCTET STRING
,        extendedData                EMBEDDED PDV
}

OptionalAbstractType                        ::=        CHOICE
{                    unused                                                             NULL
,                     opaqueString                OCTET STRING
,        extendedData                EMBEDDED PDV
}


Best regards,
Tim

From: css-csts-bounces at mailman.ccsds.org [mailto:css-csts-bounces at mailman.ccsds.org] On Behalf Of Yves.Doat at esa.int
Sent: Monday, November 01, 2010 1:04 PM
To: css-csts at mailman.ccsds.org
Subject: [Css-csts] EXECUTE-DIRECTIVE Possible redefinitions


Dear all,

I know you are all back in your daily work and quite busy so I will do my best to be short. My question is at the end of the mail.

I started to look at the EXECUTE-DIRECTIVE trying to answer the RID we discussed last week,

RID references: NASA-JVP-15. NASA-JVP-16.

Our requirements:

 1.  Enure a procedure and/or a service using the operation to have the possibility to use the operation withour extension.

 1.  Reuse the AbstractType (proposed definition as follows):
-- This type is used by operations allowing the procedures
-- using them to two possibilities for the definition of the data:
-- 1. opaqueString: direct use. No extension required
-- 2. extendedData: definition of a complex type using a constructed syntax
AbstractChoice                        ::=        CHOICE
{        opaqueString                OCTET STRING
,        extendedData                EMBEDDED PDV
}

 1.  Link the the directive qualifier to the directive identifier.

Possible redefinitions
Option 1:
 Exec-Dir
           Pro's:          - reuse AbstractChoice
                        - simple
                        - if dir-qual is not required we add a requirement to use an empty octet-string
         Con's:         - mixture octet-string & extended is possible.
                - does not link a given dir-qual to a given dir-id: dedicated requirement in the text can solve that.
                       - in case dir-qualif is not required, it cannot be mapped to a NULL value but to an empty Octet String.
        ExecuteDirectiveInvocationOption1        ::=         SEQUENCE
        {        standardInvocationHeader        StandardInvocationHeader
        ,     directiveIdentifier                AbstractChoice
        ,        directiveQualifier                AbstractChoice        -- qualifier of the directive identifier
        ,        extensionParameter                Extended
        }

Option 2:
 Exec-Dir same as option 1 but with a different dir-qualif definition
           Pro's:          - reuse AbstractChoice
                        - simple
                        - if dir-qual is not required we add a requirement to use an empty octet-string
         Con's:         - mixture octet-string & extended is possible.
                - does not link a given dir-qual to a given dir-id: dedicated requirement in the text can solve that.
       ExecuteDirectiveInvocationOption1        ::=         SEQUENCE
        {        standardInvocationHeader        StandardInvocationHeader
        ,     directiveIdentifier                AbstractChoice
        ,        directiveQualifier                CHOIDE -- qualifier of the directive identifier
                {                octetString                [0] OCTET STRING
                ,                null                        [1] NULL
                ,                extended                [2] EMBEDDED PDV
                }
        ,        extensionParameter                Extended
        }


Option 3:
            Pro's:          - does not allows octet-string & extended mixture
         Con's:          - more complex structure (but still workable)
                - AbstractChoice not reused
                - does not link a given dir-qual to a given dir-id. dedicated requirement in the text can solve that.
        ExecuteDirectiveInvocationOption2        ::=         SEQUENCE
        {        standardInvocationHeader        StandardInvocationHeader
        ,        directiveIdentification                CHOICE
                (        octetString                        [0]        SEQUENCE
                        {        directiveIdentifier                OCTET STRING
                        ,        directiveQualifier                CHOICE
                                {        selected                        [0]        OCTET STRING
                                ,        unused                        [1]        NULL
                                }
                        }
        ,                Extended                        [1]        SEQUENCE
                        {        directiveIdentifier                EMBEDDED PDV
                        ,        directiveQualifier                CHOICE
                                {        selected                        [0]        EMBEDDED PDV
                                ,        unused                        [1]        NULL
                                }
                        }
        ,        extensionParameter                Extended
        }

Notes:
- None of the options ensure a proper link between the identifier and he qualifier. We should be able to cover the link by appropriate requirements in the text
- Option 1 is the simplest but may require more requirements for a proper usage.

Could you please let me know from your opinion which option answers the best our discussions from last week.

 1.  Option 1?

 1.  Option 2?

 1.  Option 3?

 1.  New option?

Best regards
Yves
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