[cssm] SACP: configuration of tranfer services

Tue Feb 2 14:21:38 UTC 2021

Hi Marcin,

As I would see it, and as I think we had it in the old Blue-1 book, the service instance identifiers and the parameters you feel are missing are part of the service package, not the SA or CP. Your 3 spacecraft configurations would be 3 configuration profiles. The SP request may identify a specific station or antenna; at any rate, the SP itself will identify the aperture and the service instances, and at least port IDs.
There was a discussion which I don’t think was ever fully resolved, about service instance identifiers. The original concept had them being dynamically defined for each service package. But the “stop-gap” SICF approach ended up with people getting used to “permanent” SI IDs and being reluctant to change that. Certainly I think it would be unhelpful to have to reproduce the same config multiple times just to use different SI IDs for different apertures.
Basically what you suggest in your second and third bullets looks about right, modulo discussion on permanence of SI IDs.

I think the FRM parameters identified as just “reporting” mean they cannot be changed during production. Clearly they have to be set somewhere, i.e. “by management”, as part of setting up the service packages.

Anthony

From: SMWG <smwg-bounces at mailman.ccsds.org> On Behalf Of Marcin.Gnat at dlr.de
Sent: 26 January 2021 15:32
To: smwg at mailman.ccsds.org
Subject: [cssm] SACP: configuration of tranfer services

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Dear SMWG,

In course of some implementation work and discussion with my developers, I came to the point where I think we shall have some closer discussion soon (in one of our teleconferences and definitely later during spring meetings).

The protagonist: configuration (profile) of the transfer service (known currently under nicknames “SLE configuration” or “SICF”).

The place and time: somewhere in snowy Bavaria during Winter 2020/2021, Corona situation.

The Synopsis: during implementation of VEEEEEERY remotely similar profiles into DLR’s new scheduling system, my developers asked me how they shall treat the Service Instance Identifiers in the profile. When I looked at their initial implementation, I noticed, that they did put the complete configuration (service) profile in “one piece”, according to the current list from FRM and to what I told them. It does not correspond to the full flexibility of the actual planned SACP (this was not the intention). Anyhow, I realized two things:

  1.  Not all of SLE parameters were there (GVCID, Port and User identifiers, etc…)
  2.  Defined as such now, projects would need to define multiple configuration profiles, being actually the same, differing only with Service Instance Identifier, for each Service Instance. In our case, for example for TerraSAR mission, we have actual 3 spacecraft configurations for the antenna, but in total 32 service instances for different stations, antennas and cortexes. This maybe does not multiply 1x1, but at least we would need 32 configuration profiles (I can almost hear the project people coming to get me)!

Okay, this is to some extent my own fault, as I burdened the implementation of “some kind of configuration profile” to my developers, and maybe did not thought about it in front. But it shows I think also some shortcomings we have with the concept (maybe it will shape up still).

To the first point, I quickly noticed, that – even I made a list of parameters based on FRM – actually not all parameters are really exposed. When looking to the export of Holger out of FRM and the schema files, I noticed than there is number of parameters which are marked only as “reporting” thus in first place not visible to SACP (hence my omission). And so, all Initiator and Responder Id’s as well as PortId’s and the GVCID’s are marked as “reporting” or “read-only” if you like. How are we going to set them? Shouldn’t they be also configurable, similar like Service Instance ID?

From this:
[cid:image001.png at 01D6F974.59E0DE00]

To this:
[cid:image002.png at 01D6F974.59E0DE00]

Second topic is the actual (operational) separation of the antenna configuration and the transfer services configuration. Currently (at least at DLR) this looks like this:
[cid:image003.png at 01D6F974.59E0DE00]

There are few antenna configurations (which may be effectively also identical throughout different antennas) and number of SLE configurations (Service Instances). To be fully honest, the multiplication of the SLE config is just due to the different Responder ID and Port ID’s, resulting also in separate Service Instance ID, the rest of the config is typically the same (for a specific RCF or FCLTU service).

How do we want to handle that with our current concept of SACP?

I know we had some brief discussions on that, and there is some three page (chapter 3.4.2) information on intended use in the TechNote of John. It speaks relatively high level about two options, reusing SICF files (kind of an extension to the actual SACP config) and also by dynamically setting the abovementioned parameters.

First option says, that SICF files shall be there, and the Responder and Provider ID’s and Ports shall be fixed in Service Agreement and for specific Site and Mission, and later on only these shall be used. It does not actually however says anything on how actual SICF is bound to the specific Service Package nor Service Package Request nor Configuration Profile. We have Ports and their ID’s, but how do I know which SICF shall I use? Shall there be also predefined ONE fixed SICF?

Second option of using the extended/abstract parameters in Service Package  may allow for dynamic provision of the so called “scheduledSocket” which would be just the ProviderPort. So far so good, but still I miss the rest of the SLE/CSTS configuration, especially wrt to what I wrote above.

Here is where the I lost the trace of the hunted game. And maybe we need here some discussion. 😊

I was thinking – just to came into with some proposal – of the following (better ideas are welcome!):

-          To not destroy everything else we already somehow managed to set up wrt SMURF, SPDF and SACP…
-          …We could use extended list (as at the beginning) in the Service profile, with Service Instance ID, PortID’s, GVCID’s etc., having predefined some parameters (i.e. Buffer sizes), whereas leaving all of these “variable ones” undefined. That way we would have limited number of Configuration Profiles (a set of few generic ones for the spacecraft, universally engageable in every station).
-          When booking the Service Package (sending the Request) we could “overwrite” the previously mentioned parameters using AbstractParameter Class (for example “InitiatiorID” and “ServiceInstanceID” and “GVCID”). The same would be true for SPDF – the values there would be shown in AbstractParameter class (and for example additionally station defined PortID would be provided). This would allow to use all of our Books / Formates as they are, and have individual SLE configuration for each pass/service package.
-          The disadvantage of the above method would be, that there would need to be some kind of automated generation of Service Instance ID and GVCID on user side and the ProviderPort on provider side. Otherwise we come into danger of crazy users/providers not filling these parameters, or filling them wrongly or even filling them different.

Okay… I’m done for today 😉

Cheers
Marcin
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