[CESG] Magenta Book issue: "Profiles"

[Hooke, Adrian J (9000)]

Peter: I think that I agree with you. To mark the event, maybe we should take the rest of the week off?

I do think that the finer-grained "Adaptation" and "Utilization" categories are useful. I never liked the term "Application Profile" because it's too easy to confuse how the protocol is being applied with what the protocol does: that's because the word "Application" has another meaning (as in Application Layer protocol).

I also agree strongly with your assertion that if a specification is implementable, does have interoperability properties, and clearly needs to be tested, then it's a Blue Book. Mike Kearney said this another way in a private note to me earlier, in the context of interoperability testing:

I would advocate that regardless, we get to the point where Blue Books *always* require prototyping and Magenta books *never* require prototyping.  Having a state where Magenta books sometimes do and sometimes don't require prototyping would be a bad thing.  And I still like the idea of reading the book, and if you think it requires prototyping, then it must be blue... if not, it must be magenta.

So the litmus test between Blue and Magenta appears to be as stated above: it is implementable, it does have interoperability properties, and it clearly needs to be tested.

If that's true, then within the Blue category do we have the following? -

CCSDS Recommended Standard (something that internally contains a native specification developed by CCSDS)
CCSDS Recommended Standard: Adaptation Profile (something that adopts/adapts a native specification contained somewhere else)
CCSDS Recommended Standard: Utilization Profile (something that specifies how to use one or more Blue Books to perform a particular function)

It's interesting that we seem to be massaging our "adopt, adapt, develop" mantra here, by squeezing it out to "adopt, adapt, develop, use". The word Adaptation seems particularly right,  since one definition is: a written work (as a novel) that has been recast in a new form; "the play is an adaptation of a short novel".

///a

From: Shames, Peter M (313B)
Sent: Friday, February 04, 2011 11:30 AM
To: Hooke, Adrian J (9000); CCSDS Engineering Steering Group - CESG Exec
Subject: Re: [CESG] Magenta Book issue: "Profiles"

Dear Colleagues,

In the new "new document "ORGANIZATION AND PROCESSES FOR THE CONSULTATIVE COMMITTEE FOR SPACE DATA SYSTEMS"", the Draft CCSDS A02x1y2a (attached), there is considerably more text about "Application Profiles", including discussion of the need for prototyping these "stacks of protocols.  The reasoning behind this is that these types of documents do, in fact, describe something that is intended to be interoperable, for example. "IP Over CCSDS".  Since this is the case, we then need to diligently carry out the same sort of point by point interoperability tests that we do for our usual, single layered standards.

While editing this revision of the document, long overdue to be published, it became necessary to add the clause, in Annex B, pgs B-6, Sec B2.3a:


Application Profiles, in particular, may require prototype implementations and interoperability validation. Whereas these practices do not, in and of themselves, define any new standards, they do define how a set of standards are to be "stacked" in order to provide end-to-end communications services, and this functionality and correct operation must be validated. In these cases a sufficiently detailed test plan must be developed, as would be done for a Blue Book, and interoperability testing must be performed and documented in a Yellow Book test report.



Some of you may recall that we originally created the notion of Application Profiles and Magenta Books precisely to deal with the fact that they are not the same as our usual, normative, One-ISO-Layer-at-a-Time, Blue Books.   Over time we have identified other types of Magenta Books, and now it seems that we are trying to distinguish other types of Blue Books, those that are "Adaptations" of other standards, either developed in CCSDS or external by external standards bodies, and those that are "Utilizations" of other standards.   These distinctions appear to be useful ones, and I agree that MTS, LTP, and DVB-S fit into something we could call an Adaptation category and that IP Over CCSDS fits into what we could call a Utilization category.



In fact, one of our foundational Blue Books, CCSDS 401.0-B-20, "Radio Frequency and Modulation Systems-Part 1: Earth Stations and Spacecraft", has for many years been exactly a Utilization style document.  Much of this document consists of references to external standards, particularly for modulation, (NRZ, BPSK, GMSK, OQPSK, etc), and it does not define any of this within the body of the document, just how, when, and where these external standards are to be utilized.



Where I differ from Adrian, if we are going to introduce this new terminology and the associated distinctions into the "revised yet one more time" ORGANIZATION AND PROCESSES FOR THE CONSULTATIVE COMMITTEE FOR SPACE DATA SYSTEMS, is in whether we should take the position that only "Adaptations" are Blue.  Pretty clearly Adaptations will still need to have interoperability testing done, will need two independent implementations, will need to have two separate exercises of any required licensing, and will also need to have all of their clauses tested.



The exact same situation appears to be the case for Application Profiles, and other "Utilizations".  So, rather than having Application Profiles, or "Utilizations" in general, continue to be a special case of Magenta Books, the only one that requires interoperability testing, I would recommend that we declare that all Applications Profiles, and "Utilizations" in general, are Blue Books.  They are implementable, do have interoperability properties, and clearly need to be tested.   This would tend, I believe, to simplify the whole CCSDS A02x1y2 document structure and make the distinctions between Blue and Magenta rather clearer, since there would no longer be a need to explain why this class of Magenta Books, and only this, need implementations and interoperability testing, but none of the others do.



Bottom line: I support Adrian's proposal but would take it one step further, to add both Adaptation and Utilization categories to the Blue Book track.



Regards, Peter



From: Adrian Hooke <Adrian.J.Hooke at jpl.nasa.gov<mailto:Adrian.J.Hooke at jpl.nasa.gov>>
Date: Fri, 4 Feb 2011 07:24:55 -0800
To: CCSDS Engineering Steering Group - CESG Exec <cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>>
Subject: [CESG] Magenta Book issue: "Profiles"

Area Directors: as you will have observed in recent days, we are having some problems deciding whether documents should be categorized as Blue or Magenta. The latest problems have surfaced with several documents that point to external specifications in a normative way (e.g., SOIS-MTS, SIS-LTP, SLS-DVBS) rather than containing their own normative specifications. This is sometimes done for reasons of copyright, i.e., we can't simply cut-and-paste the text of another standard and make it our own. However, in all of these cases one thing is clear: we are pointing to another normative specification and adopting all of it, or a precise subset/superset of it, as our own normative technical standard. So is it a Blue Book or a Magenta Book?

Some have argued that we are essentially creating an "Application Profile" and as such the document should be Magenta. However, in the current governing documents  http://public.ccsds.org/publications/YellowBooks.aspx  (the "Procedures Manual for the Consultative Committee for Space Data Systems" and the "Restructured Organization and Processes for the Consultative Committee for Space Data Systems") there is no such formal document category as an "Application Profile Magenta Book". The Procedures Manual refers - once - to "application profiles for CCSDS specifications recommended for use in particular mission support configurations". The restructuring book notes - once - that "a Recommended Practice might specify some specific "Application Profiles" of multiple CCSDS Standards that are recommended for use in particular mission support configurations". In the still-draft new document "ORGANIZATION AND PROCESSES FOR THE CONSULTATIVE COMMITTEE FOR SPACE DATA SYSTEMS" there is a bit more proposed text about "Application Profiles", but we haven't agreed on that yet.

Clearly, we need some better guidance to help distinguish between a Recommended Standard and a Recommended Practice in the cases where we are adopting a normative "profile" of another standard. So it may be helpful to invent language to distinguish between:


a)      a profile that specifies how to accomplish a new general function by normative reference to specific normative text in some other specification(s) [e.g., LTP, MTS or DVB-S] and;

b)      a profile that specifies how to support a particular mission class by recommended reference to how some other specification(s) may be used or stacked together [e.g., IP-over-CCSDS].

We could call the former an "Adaptation Profile" that would live in a Blue Book and the latter a "Utilization Profile" that would live in a Magenta Book.

As an interesting aside, it looks like we in fact already have got internationally standardized "Adaptation Profiles" that have been certified Blue: the four Service Classes in section 7 of the CFDP Blue Book are exactly and precisely Adaptation Profiles.  We just happen to have packed them into 727.0-B-4 along with everything else related to file transfer, instead of publishing each one in its own (thin) Blue Book.  And it appears that we're doing the very same thing with Conformance Classes in the AMS book.

What's important here is that by formally recognizing these Adaptation Profiles as legitimate independent Recommended Standards we would make it possible to do flexible things (like incrementally adding more Conformance Classes to AMS or more Service Classes to CFDP)  by publishing thin, easily reviewed new Blue Books as the demands of flight mission operations evolve, without ever having to go back and hack/reissue the original protocol specs.

There are other issues to resolve with Magenta Books (concerning interoperability testing), but for now could you please comment on the above proposal?

///adrian

Adrian J. Hooke
Chairman, CCSDS Engineering Steering Group (CESG)
Space Communications and Navigation Office (SCaN)
Space Operations Mission Directorate
NASA Headquarters
Washington DC  20024-3210

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