[CMC] Re: [CESG] SM&C Overlap materials

Shames, Peter M (313B) peter.m.shames at jpl.nasa.gov
Thu Jun 10 12:20:14 EDT 2010


Hi Stuart,

Good to hear from you and thanks for the corrections and clarifications.
Try as I might it is hard to keep up with everything going on in the 6 areas
and 33 working groups.  This sort of direct feedback is useful.

Other comments in-line.

Cheers, Peter



On 6/10/10 8:39 AM, "Stuart Fowell" <Stuart.Fowell at scisys.co.uk> wrote:

> Some factual errors:
> 
> Slide 5:
> 
> 1. SOIS Application Support WG is specifying File Services, not the SOIS
> Subnetwork WG
OK, but this does not change the nature of the service.

> 2. SOIS Subnetwork WG has defined a Synchronisation Service, encompassing a
> Time Distribution function, not a "Time service". This is limited to a single
> on-board subnetwork. SOIS Application Support WG is in the process of
> publishing a Time Access Service, that provides access to an onboard time
> source. It is not specified if and how this is correlated/synchronised within
> the spacecraft (e.g. using the Subnetwork Synchronisation Service) or between
> spacecraft and ground.
> 
And this is another area where what SOIS is doing (in this case in the
Subnetwork WG) really should be coordinated within SOIS with these other
time related services and with whatever gets developed in the SE Time
Correlation and Synchronization WG (the spacecraft to ground piece).

> Slide 9:
> SOIS MTS is merely a profile of AMS together with a recommended mapping onto
> SOIS Subnetwork Packet Service, not distinct from AMS as indicated in slide 9.
> 
MTS used to be a whole separate API and transfer service.  If it is now just
what you say, an application profile for AMS and a recommended mapping, then
it might remove ambiguity to describe it in just that way, as an Onboard AMS
Application Profile and a subnet mapping, rather than as something that
still sounds like it is something separate. See examples such as "IP Over
CCSDS".

> Slides 10 & 11 are unreadable - large black boxes?
> 
Not on the PPT file here. See attached PDF and see if that helps.

> Slide 11:
> I've no idea what "Given SOIS changes, are there other overlaps since this
> 2004 MoU?" means. What SOIS changes?
> 
Between 2004 and now SOIS has undergone a number of shifts in organization
and intended product set.  I was using this existing SOIS - MOIMS MOU, dated
9 May 2004, as a baseline for discussion and did not try and update it to
reflect current reality.  Perhaps it is time for SOIS and MOIMS to revisit
this MOU.  MOIMS SM&C has also made significant changes in the past 6 years.

> In general:
> All SOIS services are onboard only, as per charter and explicit in the name!
> An onboard implementation of SM&C services is treated as a SOIS application
> and can make use of any SOIS service. This goes for CFDP, DTN etc.
> 
I do not think that I ever in any way suggested that SOIS was anywhere but
onboard.  In fact, the only diagrams I have ever used in relationship to
SOIS are SOIS diagrams or this diagram from a SOIS / MOIMS MOU that SOIS
agreed to.  The Figures on pgs 10 & 11 are from this MOU.

Your last comments, however, are a little puzzling.  How is it that SM&C
services, CFDP, and DTN suddenly become "SOIS Applications" as you suggest?
There are certainly a variety of spacecraft and science applications and
protocol elements that are onboard, but how does being onboard a spacecraft
make them "SOIS Applications" excpet in apurely contextual sense?  Just
looking at the SOIS - MOIMS MOU figure on pg 11 it would appear that the SLS
and SIS protocol "services" are on a par with the related SOIS data
transport services, and that SOIS, MOIMS, and other mission specific
applications may use SLS, SIS, SOIS, or MOIMS (or other) services as needed.

> Please talk to SOIS...
>  
OK.  Do we need to have a SOIS telecon to sort through any remaining issues
or misunderstandings?  Do you (and Chris, Nestor & Roger) think we need to
revisit the MOU given the changes in both areas work plans and product sets?
Do we need to further revise the MOU to be a more general document,
something like a SOIS to SM&C, SLS, SIS MOU?

Thanks, Peter


> Stuart D. Fowell BEng MBCS
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> -----Original Message-----
> From: cesg-bounces at mailman.ccsds.org [mailto:cesg-bounces at mailman.ccsds.org]
> On Behalf Of Shames, Peter M (313B)
> Sent: 10 June 2010 16:18
> To: CCSDS Engineering Steering Group - CESG Exec; Mike Kearney; Hooke, Adrian
> J (9000); CMC
> Subject: [CESG] SM&C Overlap materials
> 
> Here is the overlap analysis, specifically of SM&C but involving other areas,
> that I did back in Sept 09.  On pg 18 is the specific set of areas of overlap
> that I identified, cross cutting MOIMS, CSS, SIS, SEA, and SOIS.
> SLS is blissfully left out of this discussion.
> 
> This ought to be a very good focal point for starting a focused overlap
> analysis.  The materials that Erik and the RA SIG developed that focus on the
> Messaging overlaps is an example of how to take this the next step of detail.
> It needs refinement, but is a really good start.
> 
> Once we have these analyses done in any given topic area we can then do the
> harder work of sorting out how to resolve the actual overlaps.
> 
> Regards, Peter
> 
> 
> 
> _______________________________________________________
> 
> Peter Shames
> Manager - JPL Data Systems Standards Program InterPlanetary Network
> Directorate Jet Propulsion Laboratory, MS 301-490 California Institute of
> Technology Pasadena, CA 91109 USA 
> 
> Telephone: +1 818 354-5740,  Fax: +1 818 393-6871
> 
> Internet:  Peter.M.Shames at jpl.nasa.gov
> ________________________________________________________
> "We shall not cease from exploration, and the end of all our exploring will be
> to arrive at where we started, and know the place for the first time"
> 
>                                                                             
>                 T.S. Eliot
> 
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_______________________________________________________

Peter Shames
Manager - JPL Data Systems Standards Program
InterPlanetary Network Directorate
Jet Propulsion Laboratory, MS 301-490
California Institute of Technology
Pasadena, CA 91109 USA 

Telephone: +1 818 354-5740,  Fax: +1 818 393-6871

Internet:  Peter.M.Shames at jpl.nasa.gov
________________________________________________________
"We shall not cease from exploration, and the end of all our exploring
will be to arrive at where we started, and know the place for the first
time"

                                                                            
                T.S. Eliot




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