[Smwg] AI2018-0411014: Update Ref-Framework diagram and add to Interrecommendation...

John Pietras john.pietras at gst.com
Tue Oct 9 13:18:12 UTC 2018

Regarding the question of whether the Simple Schedule addresses offline service packages, one of the ServiceType values is "OFFLINE-TM-PROVISION", which I have always assumed maps to an Offline Service Package. If that is not the case, then what does OFFLINE-TM-PROVISION refer to?

While it is true that the goal (assumption) in general is that offline services don't need to be scheduled, we have made provisions for needs to do such scheduling in networks that are terrestrial WAN constrained. The concept is that Offline Service Packages can be sporadically instantiated (e.g., scheduled) if the need exists, or they can be set up long term (e.g., for the duration of the Service Agreement) if there are no constraints on provisioning of ground bandwidth - the only difference is in the start and stop times of the Offline Service Package. The Functional Resource Reference Model contains different "Configuration Categories" to support "Online" Service Packages (the Space Link Session (SLS) configurations that involve an active space link) and "Offline" Service Packages (the Retrieval configurations for offline/complete return services and the (currently only one) Forward Offline configuration for the Forward File service).

With regard to the question of whether Offline Service Packages are evident in the Simple Schedules, the simple answer (no pun intended) is that if a Provider CSSS doesn't need to *schedule* offline services - i.e., they are available 24/7 - then they don't appear in the Simple Schedule. But if they do need to be scheduled, then they could appear in the Simple Schedule with the ServiceType OFFLINE-TM-PROVISION. However, as currently constructed, the Simple Schedule makes the OFFLINE-TM-PROVISION service part of a "ScheduledActivity" that is essentially defined as a pass or track. By this construction the provision of the offline TM "service" is defined as occurring between the beginningOfActivity and the endOfActivity. Offline playback is often (or even mostly) time-discontinuous with space link session through which the played-back data are acquired. So the EndOfActivity would have to envelope the end of the last period that any of the data is scheduled to be played back. That could result in an "activity" that spans a week even though the duration of the "track" itself is only 15 minutes.

It's also reasonable to question how useful the Simple Schedule-level information is with regard to such offline services. That is, who would care whether such entries appear in a Simple Schedule?


From: SMWG <smwg-bounces at mailman.ccsds.org> On Behalf Of Eddy, Wesley M. (GRC-LCN0)[MTI SYSTEMS, INC.]
Sent: Monday, October 08, 2018 9:46 PM
To: Barkley, Erik J (JPL-3970)[Jet Propulsion Laboratory] <erik.j.barkley at jpl.nasa.gov>; Marcin.Gnat at dlr.de; smwg at mailman.ccsds.org
Subject: Re: [Smwg] AI2018-0411014: Update Ref-Framework diagram and add to Interrecommendation...

Just as a datapoint, I will say that In the SN, scheduling of playbacks is a way to make sure that offline services don't impact simultaneous online services sharing the bandwidth of the ground network WAN links.  That network capacity is treated as a resource by the scheduling system.  There are potentially other ground resources that could have capacity constraints (e.g. I/O bandwidth of a disk array, etc) which might make it preferable to schedule offline services in some cases ... Though I would agree that it does seem counter-intuitive, and there are possibly other decent ways to deal with preventing impact to online services..

From: SMWG <smwg-bounces at mailman.ccsds.org<mailto:smwg-bounces at mailman.ccsds.org>> On Behalf Of Barkley, Erik J (3970)
Sent: Friday, October 5, 2018 6:30 PM
To: Marcin.Gnat at dlr.de<mailto:Marcin.Gnat at dlr.de>; smwg at mailman.ccsds.org<mailto:smwg at mailman.ccsds.org>
Subject: Re: [Smwg] AI2018-0411014: Update Ref-Framework diagram and add to Interrecommendation...

Hello Marcin,

I think we have an additional item for the Berlin meetings - double check the updated reference framework.  I have included this on the agenda for Thursday morning of the meeting week.

Re your questions:

1)      "-  The Service Package has no reference to the Service Agreement (possibly it should have)"   Yes, I think it should.  And perhaps this is something to consider as optional in the common information entities magenta book. No doubt more discussion at the meetings in Berlin.

2)      -    "Simple Schedule does not include at the moment Offline Service Package, or?".  My preference would be to keep the off-line service packages out of the simple schedule definition. The rationale being that the notion of an off-line service package is frankly rather archaic by today's standards (the SSF is really about who is utilizing which aperture and not who is scheduling access to an archive - really I have to schedule access to an archive?).  I believe that if an implementation really needs to note that data retrieval/off-line service packages are scheduled that can be accommodated by adding an appropriate implementation unique extension parameter or parameters but I don't think there is really a widely supported business case here.  Perhaps yet more discussion in Berlin :)

Best regards,

From: SMWG <smwg-bounces at mailman.ccsds.org<mailto:smwg-bounces at mailman.ccsds.org>> On Behalf Of Marcin.Gnat at dlr.de<mailto:Marcin.Gnat at dlr.de>
Sent: Thursday, September 27, 2018 04:46
To: smwg at mailman.ccsds.org<mailto:smwg at mailman.ccsds.org>
Subject: [Smwg] AI2018-0411014: Update Ref-Framework diagram and add to Interrecommendation...

Dear All,

I worked out new FW-references. This is something one calls major rework, I suppose.
Should fit to the current status of our Information Entities. There are two points which came to me when doing:

-          The Service Package has no reference to the Service Agreement (possibly it should have)

-          Simple Schedule does not include at the moment Offline Service Package, or?

Aside, I used some coloring, to group the entities (grey - offline, orange/red - online related, blue - planning and green reporting).

Please have a look at the updated diagram below:
[cid:image001.png at 01D45FA9.84EC56E0]
Also I have uploaded new Interrecommendation Worksheet (which btw. includes newest State Machines as well):

The Visio File for the Model itself:

Best regards

Marcin Gnat

Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)
German Aerospace Center
Space Operations and Astronaut Training | German Space Operations Center (GSOC) | Communications and Ground Stations
Oberpfaffenhofen, 82234 Wessling, Germany

Marcin Gnat | Team Leader Ground Data Systems
Telephone +49 (8153) 28 3201 | Telefax +49 (8153) 28 1456 | marcin.gnat at dlr.de<mailto:marcin.gnat at dlr.de>

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