[CESG] IOAG: Service Catalogue #1 / "packet / file / frame plumbing"

Shames, Peter M (312B) peter.m.shames at jpl.nasa.gov
Tue Sep 27 16:15:25 UTC 2016


Hi Gippo,

Please go look at the SCCS-ADD (or ARD) which have carefully prepared (and reviewed) diagrams that show just exactly what is involved in providing the F-Frame service and an ABA forward file service built on top of it.  You are quite right that "Space/Encapsulation Packets, reliable/unreliable transfer, COP usage" are functions that will need to be built to operate the service and that it will be necessary to also define and build the Service Management (SM) capabilities that will allow these functions to be requested, managed, and configured by the service user.  But that is not all that will be required.

The more significant "plumbing" that I was referencing includes: CFDP protocol processing, SPP packet creating, frame creation (AOS or TC), frame merging & multiplexing into separate VCs, and frame encoding.  All of those functions are defined in the ADD, some assigned to F-Frame (from frame creation down), as a re-usable set of structures, and some to specific services (such as CFDP and SPP).  And all of those functions also need SM capabilities defined.  Furthermore, those functions, as defined in the F-Frame service description, are re-usable and can support both ABA and SSI protocol stacks and end-to-end services.

To say that the "IOAG File services suppose a file is passed from A to B" is to ignore all of the actual plumbing that is required to make this happen.  From a simplistic, "top level", view this may be acceptable, but from a protocol view we really need to understand and define the whole set of protocols in the stack(s) and the gyrations that they go through.  We cannot ignore the plumbing.  So, in order to define a set of services that maximize functionality for the users and minimize the effort on the part of the ESLT (and the users) we took the approach defined in the SCCS-ADD.  You were one of the reviewers and approvers of that document, I assumed you were familiar with it.

I hope you recall that the origins of this F-Frame approach was in the IOAG SISG, in a sub-committee that you, Wolfgang, and I participated in.  The focus there was on space internetworking, but the forward frame service we cooked up was a general one and entirely suitable for the "plumbing" of even these sorts of ABA services.  And that is exactly what is described in the SCCS-ADD.

I think we should stick to the plan of developing the F-Frame first, and building these other services on top of that framework instead of developing another collection of "one-off" SLE-like services.

Regards, Peter



From: Gian Paolo Calzolari <Gian.Paolo.Calzolari at esa.int>
Date: Tuesday, September 27, 2016 at 8:53 AM
To: Peter Shames <peter.m.shames at jpl.nasa.gov>
Cc: CCSDS Engineering Steering Group - CESG Exec <cesg at mailman.ccsds.org>, CESG <cesg-bounces at mailman.ccsds.org>, Nestor Peccia <Nestor.Peccia at esa.int>
Subject: Re: [CESG] IOAG: Service Catalogue #1 / "packet / file / frame plumbing"

Peter,
        I am sure I really understand what you mean for  "packet / file / frame plumbing"?
It looks to me that the description in Catalog 1 for the four files services (two directions x two flavours) do underline that the service provide will have to do quite some work (plumbing?) about Space/Encapsulation Packets, reliable/unreliable transfer, COP usage,
You also say the  CSTS F-Frame is supposed to provide most of this plumbing but yor comment is ot about IOAG Catalog bu rather about the service an agency should select.
In fact the IOAG File services suppose a file is passed from A to B, while F-Frame supposes frames are passed fromA to B.

Regards

Gian Paolo



From:        "Shames, Peter M (312B)" <peter.m.shames at jpl.nasa.gov>
To:        "Nestor.Peccia at esa.int" <Nestor.Peccia at esa.int>, "CCSDS Engineering Steering Group - CESG Exec(cesg at mailman.ccsds.org)" <cesg at mailman.ccsds.org>
Date:        26/09/2016 21:33
Subject:        Re: [CESG] IOAG: Service Catalogue #1
Sent by:        "CESG" <cesg-bounces at mailman.ccsds.org>
________________________________



Nestor,

I know that this is a late input, but after reading the IOAG Svc Cat #1 I have a very real concern that I think needs to be surfaced.  Four new services have been introduced, the "Forward/Return CFDP-File Service Type" and the "Forward/Return PACKETS-File Service Type".  In reading through the descriptions I find that they mention certain SM characteristics, but fail to acknowledge the required presence of a whole lot of "packet / file / frame plumbing" that is missing in most of our current systems.  Of particular concern, from a standards and logistics point of view, is that these new standards require a lot of the "plumbing" that CSTS F-Frame is supposed to provide, but make no mention of that standard.  In fact, the precursor standards, "Forward Synchronous Encoded Frame Service Type" has been dropped, and what is left is just some sort of weak "forward reference" to a CSTS F-Frame service.

I think this is a huge mistake and that we should push back on it.

Here is the logic behind this:

1)       FF-CSTS includes the key services and functions that are required for anything like forward file, or forward packet, or forward DTN to work.
2)       These functions include, quoting from the report "Users shall be aware that IOAG Service Catalog 2 foresees a future CSTS Forward Frame Service that is assumed will provide a forward service for [AOS] and [TC-DLP] frames implementing multiplexing, frame fill and coding in the provider and implementing the full stack down to the physical layer."
3)       In order to implement a forward file or packet service all of these functions, plus frame creation, must be present in the service provider.
4)       It makes little technical sense to create forward file and forward packet services, as new separate services that embed all of these function, instead of creating the FF-CSTS service and then building CFDP and Packet service "plug-ins" on top of that which use this underlying service.

In fact, this approach is exactly how the forward file service is now described in the SCCS-ADD.  I draw your attention to CCSDS 901.1-M-1, sec 5.2.2.2 and sec 6.2.2.2.  In fact, fig 6-4 shows the relationships among SM, CSTS F-Frame, the associated functions that are required, including ranging, and also SLE R-AF, and fig 6-8 (ABA ESLT Forward-File Protocol Building Blocks) shows how F-Frame and Fwd frame are designed to be integrated.  Any sort of forward packet service ought to just be a variant of this.

My recommendation is that CCSDS push back on this IOAG Cat 1 request for two new stand alone services and instead argue that CSTS F-Frame should be done first, and these other new service built upon that base.

Regards, Peter



From: CESG <cesg-bounces at mailman.ccsds.org> on behalf of Nestor Peccia <Nestor.Peccia at esa.int>
Date: Thursday, September 15, 2016 at 3:43 AM
To: CCSDS Engineering Steering Group - CESG Exec <cesg at mailman.ccsds.org>
Subject: [CESG] IOAG: Service Catalogue #1

REMINDER

Please let me have your comments (in particular from the CSS Area) by 22nd Sept 2016 cob.

ciao
nestor

============================
Dear all,

Please  find attached the Service Catalogue #1 that has been approved by the IOAG.

You should be aware that the final approval regarding the editorial updates from NASA is still pending. There is an on-going discussion concerning service management “function” vs. service management “service”.

However, this version is good enough to be processed by the CESG.


[attachment "IOAG Service Catalog One.v2.0-Approved-20160823.pdf" deleted by Nestor Peccia/esoc/ESA]
[attachment "IOAG Service Catalog One.v2.0-Approved-20160823withBars.pdf" deleted by Nestor Peccia/esoc/ESA]

CESG will address this update during our next webex.

Main changes are :
1.        forward / return CFDP file over terrestrial generic file
2.        forward / return packet file service  over terrestrial generic file
3.        Service Management functions


ciao
nestor
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