[CESG] IOAG: Service Catalogue #1 / File Services warning (complete)
Scott, Keith L.
kscott at mitre.org
Tue Sep 27 17:08:33 UTC 2016
Right, this is the notion in the ICPA of what Chris Taylor referred to as ‘first-hop / last-hop’ services. If you’ve got a spacecraft that is otherwise SSI-aware but is now in trouble, it might not HAVE DTE capability and the only way to get emergency link-layer commands to it (assuming it was built to do that, which seems reasonable) would be to ship a bunch of frames to some SSI-enabled spacecraft NEAR the troubled one, then blast those frames at the troubled one. My notion is that this is a standardized application that could be present on all (ok, many) SSI-enabled spacecraft, and the standardization bit is in how to express the ‘here’s what to send and here’s how to send it’ part. The content (data + instructions) is shipped to the functioning spacecraft over one of the the SSI networking protocols (BP or IP).
My understanding is that the FF service takes frames, moves them somewhere, combines them with other stuff and/or does whatever needs to be done to form a transmittable serialized stream of bits, and hands that stream off for radiation. If that understanding is correct, if I use bundles as the shipment mechanism, FF service is pretty much a description of the SSI first hop / last hop service. And, I hope that unless there’s a need to be more specific, the forward frame service could use any number of underlying mechanisms for shipment (e.g. TCP/IP suite, BP, etc.)
--keith
From: "Tomaso.deCola at dlr.de" <Tomaso.deCola at dlr.de>
Date: Tuesday, September 27, 2016 at 12:59 PM
To: Peter Shames <peter.m.shames at jpl.nasa.gov>, Gian Calzolari <Gian.Paolo.Calzolari at esa.int>, Keith Scott <kscott at mitre.org>
Cc: "cesg-bounces at mailman.ccsds.org" <cesg-bounces at mailman.ccsds.org>, CCSDS Exec <cesg at mailman.ccsds.org>
Subject: RE: [CESG] IOAG: Service Catalogue #1 / File Services warning (complete)
If I don’t misinterpret Keith’s statement, I think it is about exploiting tunneling capabilities of the bundle protocol so that is able to transport “blindly” CCSDS frames. Obviously we don’t want to flip the CCSDS protocol stack.
Tomaso
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Deutsches Zentrum für Luft- und Raumfahrt (DLR)
German Aerospace Center
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Tomaso de Cola, Ph.D.
Telefon +49 8153 28-2156 | Telefax +49 8153 28-2844 | tomaso.decola at dlr.de<mailto:tomaso.decola at dlr.de>
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From: CESG [mailto:cesg-bounces at mailman.ccsds.org] On Behalf Of Shames, Peter M (312B)
Sent: Tuesday, September 27, 2016 6:35 PM
To: Gian.Paolo.Calzolari at esa.int; Scott, Keith L.
Cc: CESG; CCSDS Engineering Steering Group - CESG Exec(cesg at mailman.ccsds.org)
Subject: Re: [CESG] IOAG: Service Catalogue #1 / File Services warning (complete)
Gotta say I agree with Gippo on the last part of this. I too found that "forward frame service running over bundles" statement very confusing. Was it a typo?
The operating assumption, as documented in SCCS-ADD, is that DTN bundles run on top of CCSDS frames and thus on top of CSTS services, not underneath them.
Peter
From: Gian Paolo Calzolari <Gian.Paolo.Calzolari at esa.int<mailto:Gian.Paolo.Calzolari at esa.int>>
Date: Tuesday, September 27, 2016 at 8:32 AM
To: Keith Scott <kscott at mitre.org<mailto:kscott at mitre.org>>
Cc: CCSDS Engineering Steering Group - CESG Exec <cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>>, CESG <cesg-bounces at mailman.ccsds.org<mailto:cesg-bounces at mailman.ccsds.org>>, Nestor Peccia <Nestor.Peccia at esa.int<mailto:Nestor.Peccia at esa.int>>, Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Subject: Re: [CESG] IOAG: Service Catalogue #1 / File Services warning (complete)
Keith,
try to keep in mind that an IOAG Service is indeed a collection of Space Link Interface Standards & Ground Link Interface Standards.
Moreover, as Nestor underlined, Catalog 1 is for ABA configuration and the CFDP transmission only covers the single hop space to ground (or vice versa).
When you say " I understood the forward file service to have evolved into a mechanism/semantic for zipping a bunch of stuff together (metadata, data, etc.) " I think you refer to the Ground Link Interface Standard under development in CSS; i.e. only to a part of the IOAG Serrvice.
Last but not least I am very puzzled by the statement "forward frame service running over bundles". Catalog 2 states that <<The CSTS Forward Frame Services above is “to be written”. It is assumed that this Service will provide a forward frame service for [AOS] and [TC-DLP] implementing multiplexing, frame fill and coding in the provider and implementing the full stack down to the physical layer>> so having AOS or TC frames running over bundles would reverse our CSCDS Stack where are bundles that - throug e.g. encapsulation service - run over AOS and TC frames.
Regards
Gian Paolo
From: "Scott, Keith L." <kscott at mitre.org<mailto:kscott at mitre.org>>
To: "Shames, Peter M (312B)" <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>, "Nestor.Peccia at esa.int<mailto:Nestor.Peccia at esa.int>" <Nestor.Peccia at esa.int<mailto:Nestor.Peccia at esa.int>>, "CCSDS Engineering Steering Group - CESG Exec(cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>)" <cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>>
Date: 26/09/2016 22:06
Subject: Re: [CESG] IOAG: Service Catalogue #1
Sent by: "CESG" <cesg-bounces at mailman.ccsds.org<mailto:cesg-bounces at mailman.ccsds.org>>
________________________________
Peter,
I think I agree with you. My concern from the beginning has been that I do not want the forward file service to morph into a way to try to do multi-hop forwarding using file transfers as the ‘data link’ mechanism. I understood the forward file service to have evolved into a mechanism/semantic for zipping a bunch of stuff together (metadata, data, etc.) to be used by the end system application (the receiver end of the data transfer), with possibly some application semantics layered on top.
In fact, if the forward-XXX services were generalized just a bit, I think they’d cover the DTN emergency command/telemetry case. Or maybe the DTN emergency commanding service is the forward frame service running over bundles, I hadn’t thought of that until now but I like it. If part of the CSTS forward-frame service states how to tunnel (in my case, FRAMES) to a remote location and then radiate them, and if it can be run over BP as a transport mechanism… It would address an IOAG need, at least.
--keith
From: "cesg-bounces at mailman.ccsds.org<mailto:cesg-bounces at mailman.ccsds.org>" <cesg-bounces at mailman.ccsds.org<mailto:cesg-bounces at mailman.ccsds.org>> on behalf of Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Date: Monday, September 26, 2016 at 3:33 PM
To: Nestor Peccia <Nestor.Peccia at esa.int<mailto:Nestor.Peccia at esa.int>>, CCSDS Exec <cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>>
Subject: Re: [CESG] IOAG: Service Catalogue #1
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<mailto:cesg-bounces at mailman.ccsds.org>> on behalf of Nestor Peccia <Nestor.Peccia at esa.int<mailto: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<mailto: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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