[Sea-sa] Feedback on the current ASL GB Draft

ramon krosley r.krosley at andropogon.org
Mon Jun 4 20:54:11 UTC 2018

Hi Peter,

Thanks for this guidance; it’s always helpful to know where the work is needed.

I agree with your observations on the SOIS material; you should see my running shoes (minimal, but not barefoot).  The work on the SOIS EDS & DoT green book during the last couple of months has produced some highly detailed descriptions of the process for generating device services from SEDS, which I intend to summarize at a higher level of abstraction in the ASL green book.  I think that will address at least some of your concern.



From: Shames, Peter M (312B) <peter.m.shames at jpl.nasa.gov> 
Sent: Monday, June 4, 2018 2:32 PM
To: Roger Thompson <roger.rocketbrain at btinternet.com>; Ramon Krosley <r.krosley at andropogon.org>
Cc: SEA-SA <sea-sa at mailman.ccsds.org>
Subject: Feedback on the current ASL GB Draft
Importance: High


Hi Guys,


Over the last few days I have been reading through the current (or latest) ASL GB draft.   I think that you guys have made great progress and this document is coming together rather nicely.  At this point I am up to page 61, the end of Section 4, or something like 1/3 of the way done.


In the attached version you will see my mark-up notes.  There are a lot of inputs that are simply editorial, and others that are somewhat more substantive.  In the "substantive" column I would put the following:


1.	Most of what is now in Sec 1.1 really, IMHO, belongs in Sec 1.3, Rationale.  This is the expected usage in CCSDS Green Books, but they have been known to vary.
2.	The MOIMS sections that I have reviewed so far. are very good and quite complete.  In fact, they almost seem too complete, but that is another discussion. If everything is done to this level, as it should be to have an "even" appearance, the doc will be huge.
3.	The handling of the interfaces between MOIMS and CSS does not strike me as satisfactory.  The MOIMS MO services must plan for space links, send data over space links, and get data of various kinds from space links.  It just does not seem acceptable to say " telemetry acquisition and telecommand uplink are communications layer functions that do not directly interact at the application layer with MOIMS functions ".  If not MOIMS, then where?  Is there an air gap?  Does some other CCSDS area have responsibility?  In SCCS-ADD parlance it is "applications" that interact with the SLE and CSTS services.  Those application, IMHO, ought to be MOIMS.
4.	The SOIS materials, by contrast, are good, but seem really incomplete.  Notwithstanding that the scope of SOIS is considerably less than that of MOIMS, the treatment of the SOIS functions and services is itself truncated in the extreme.  As much as MOIMS seems a little overblown, SOIS seems totally underinflated.  I think we need to seek parallel construction in each of the sections wherever possible.  See in particular my comments in Sec 2.4.2 and 4.3.
5.	Some of the SOIS limitations are due to the "silverizing" activity that occurred, some of it seems due to a shift in focus by the leadership to implementation approaches and EDS.  Regardless, those SOIS functions and features (support, subnet, wireless) that remain in MB and GB materials really should be adequately covered in this document.
6.	I like the materials in Sec 3.3, but worry a little that we may be putting too much "RASDS 2.0" materials into this document.  There may not really be much choice, because we have agreed to use these extensions and really must explain what we are doing and why, but it is a little concern.
7.	The distinctions in type and representation that are used in Sec 3.3 among unspecified, published, under development, proposed, and "no standard identified" seem, in general, to be not sufficiently distinct to be useful.  I think the important distinction is really only between "do we have a standard" and "do we have any sort of plan for a standard".   Everything else is just so much idle speculation.  Three levels are probably enough: "it exists", "we have a plan for it", and "something could be (might be) here, but isn’t".


I'll keep on plugging away at this.  Do take a look and see if what I have identified seems reasonable or really off base.


Thanks, Peter


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