[Smwg] RE: Abstract service request telecon notes
Barkley, Erik J (3970)
erik.j.barkley at jpl.nasa.gov
Fri Jul 3 00:40:17 UTC 2015
I recognize more or less the process you have described and there are definite similarities to what I am most familiar with in terms of business process model, lifecycle, for delivery of TT+C services for the DSN. But there may be other organizations that don't quite do things the same way or perhaps are using a request in sense that does not have the all of the supporting details (such as service agreement, configuration profile, event sequence) etc. in place. For example, assuming we are wildly successful (why not?) it may be that someday we have a normative recommendation includes a request for creation of a service agreement. It may be that there are constraints expressed for each service on an independent basis or at least in some relatively de-coupled manner.
Part of what we are attempting to do here is understand what are the components needed for a service request in the abstract and so this is probably best viewed as an M-2 model. The idea is to understand what and where are the functional points of articulations for requests in general. Its kind of functional resources for service request. At the M-2 level I tend to be satisfied that there is, in the abstract, a constraints function. This then is an essential extensibility point that can be subject to restrictions such as you indicated below (ie, constraints only on the entire package of services).
I think we will know more at our next discussion on this when we see the planning request vs (a more exact DDOR flavored) service package request being compared and contrasted. In both cases there will likely be some sort of constraints, some sort of service configuration function, some sort of ability to reference other information, etc - these are the items of primary interest at the moment.
From: Holger.Dreihahn at esa.int [mailto:Holger.Dreihahn at esa.int]
Sent: Wednesday, July 01, 2015 2:43 AM
To: Barkley, Erik J (3970)
Cc: Colin.Haddow at esa.int; Chamoun, Jean-Pierre (GSFC-458.0)[Affiliate] (jean-pierre.chamoun at nasa.gov); Marcin.Gnat at dlr.de; CCSDS Service Mgmt WG; Unal, Martin P (9020-Affiliate)
Subject: Re: Abstract service request telecon notes
Thanks for the opportunity to join the discussion. Having a second thought about the request and the discussed option to attach constraints to the provided services I was considering the following:
- for the request itself constraints make sense to express flexibility, something like 'I need a an 8-10h pass starting earliest at 12h, latest start at 14h.
- for the services within the pass I am not that convinced (anymore):
\ not all required details might be known at request time
\ according to my experience missions want to prescribe an exact timing when services (uplink, ranging, doppler measurement etc.) are provided within a pass
In our network we now at pass request time the set of required services, the station capability in terms of service provisioning and perform the booking (station allocation plan). However, at that point in time some details for the service provisioning within the pass are not known. Typically at a later stage missions provide (often by providing mission specific events) the details, which allows the production of executable station schedule, which actually refines the station allocation plan into a more detailed schedule which logically contains the service provision times (and parameterisation) of the provided services within a pass. In addition to that there may be the need to update the pass allocation timing at a later stage based on updated orbital predictions.
I would expect that scenario to be typical for network: Resources (station and others) are booked quite in advance. At this time often not all information (e.g. orbital predictions) is available at the finally required precision to actually schedule station services correctly. If that is true, shouldn't we reflect that in the abstract service request, i.e. simplify it to what's needed. In our network the equivalent of the service agreement captures the rules when services are provided within a pass, often this is done by referring mission specific events. Now I do not know exactly, but I would expect the sequence of events to provide a similar sort of functionality.
As such it looks to me we are mixing up two problems: Station (resources) allocation and service scheduling within the allocated passes. Is that necessarily a good idea? I think this is a fundamental point we need to discuss. According to a discussion with Martin the resource allocation request need the outlined flexibility to facilitate better resource exploitation. Services within a pass have to be provided according to precise timings with agreed and validated (parameterised) setup.
The resource allocation is typically an input to mission planning, which results later in the details required to provide the service within the allocated resource booking.
For the constraints of the request itself I would rate composition (black diamond) as the right way of doing it. For service specific constraints (or details, rules or what it will be) I tend to agree that those should be references to, ja, do not know exactly but some (static) configuration like the rules captured by the service agreement.
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From: "Barkley, Erik J (3970)" <erik.j.barkley at jpl.nasa.gov<mailto:erik.j.barkley at jpl.nasa.gov>>
To: "Chamoun, Jean-Pierre (GSFC-458.0)[Affiliate] (jean-pierre.chamoun at nasa.gov<mailto:jean-pierre.chamoun at nasa.gov>)" <jean-pierre.chamoun at nasa.gov<mailto:jean-pierre.chamoun at nasa.gov>>, "Marcin.Gnat at dlr.de<mailto:Marcin.Gnat at dlr.de>" <Marcin.Gnat at dlr.de<mailto:Marcin.Gnat at dlr.de>>, "Colin.Haddow at esa.int<mailto:Colin.Haddow at esa.int>" <Colin.Haddow at esa.int<mailto:Colin.Haddow at esa.int>>, "Holger.Dreihahn at esa.int<mailto:Holger.Dreihahn at esa.int>" <Holger.Dreihahn at esa.int<mailto:Holger.Dreihahn at esa.int>>,
Cc: CCSDS Service Mgmt WG <smwg at mailman.ccsds.org<mailto:smwg at mailman.ccsds.org>>
Date: 01/07/2015 03:38
Subject: Abstract service request telecon notes
Colin, Marcin, JP, Holger,
Attached are the notes from our June 30 splinter session teleconference on engineering an abstract service request. The notes have also been uploaded to the CWE. Corrections and/or comments appreciated.
-Erik[attachment "2015-06-30-AbstractSvcReq-TeleconferenceNotes.docx" deleted by Holger Dreihahn/esoc/ESA]
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