[Cesg-all] Re: [Css-csa] Current draft of the Space Communication Cross Support Architecture Requirements Document (SCCS-ARD)

[Shames, Peter M (312G)]

Takahiro,

Thank you so much for taking the time to go through this document again.
Your feedback has been very useful.  I do have Skype on my system and we
should have a speakerphone available, but I am not certain of this.  I
have heard from Nestor and others that phone accommodations may be a
problem and that Internet access is also limited.  I will check into this
once I am in Noordwijkerhout and will let you know what might be possible.

As for the meetings themselves, we have a bit of a scheduling problem.  It
appears that the CSA meeting that is on the meeting room schedule for
Tuesday AM (see attached) did not appear in the registration list. As a
result no one signed up for that session.  We do have people signed up for
the Thursday AM & PM sessions.  But the compressed four (4) day work
schedule also has the Boot Camp and the CSA WG scheduled on Thursday in
the afternoon.  I must be there to present the Boot Camp materials for the
first hour.  The CSA WG could meet in the AM and then from from 1430 to
1600 in the afternoon if people are wiling.  Please let me know your
availability.

I did read through your comments and it appears that the primary point you
are making is that there is a significant amount of repetition and
probably more specificity than you think is appropriate. In the interest
of reducing the size of the document I will agree to remove all of the
repetition.  The question of the added specificity is one that I think we
will need to discuss, but I do agree that including the added specificity
does increase the size of the document.

An example of this added specificity is stating a user requirement for TC
frames and then also stating a requirement to do encoding, produce CLTUs,
and (optionally) perform the COP.  The reason for taking this approach is
that there are at least three different specs involved in this, TC (33),
TC sync & channel coding (11), the COP (75) and the SCID (34).  Unless
someone is familiar with all of these and how they are to be stacked up it
may not be obvious that they are all needed nor how they should be used.
We could combine this sort of thing into one requirement with a specific
list of sub-clauses for clarity, but I do not know that this helps with
the size of the document. We could also drop all of the more specific
references, but at some loss of clarity for those not familiar with these
specs.

We also have this issue of people generally wanting "singular" requirement
and not compound ones.  We hear this from the ECSS reviewer (and otehrs)
all the time.  So while I agree that there is an implied amount of
redundancy by using this approach it also brings greater clarity for the
reader.  In your OSCP (10) you provide a good overview of how the space
data link and lower protocols stack up, but that is a Green Book.  This
document may be the best (only) place to provide concrete and normative
guidance of how all of these specs should be stacked and deployed.

I am open to feedback from everyone.  Are we better off reducing the size
of the document, at the risk of not being clear what is really involved in
many of these deployments, or are we better off taking this more complete
approach at the risk of making the document larger?

Best regards, Peter



On 3/20/14 6:55 PM, "Takahiro Yamada" <tyamada at isas.jaxa.jp> wrote:

>Peter,
>
>> The current version of the SCCS-ARD has been loaded to the CWE at in
>>the CSS-CSA Draft Documents folder:
>
>Thank you very much for updating the document. I could finally review it,
>and a copy of the document with my comments is attached here. All of my
>comments are minor and editorial, and I don't think we need a deep
>discussion to resolve them. You can just either accept or reject each of
>them. Please let me know if any of my comments is contentious.
>
>I can participate in any of the CSA WG sessions during the CCSDS meeting
>either by Skype of phone. Please let me know when I should join you.
>
>Best regards,
>Takahiro Yamada

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