[Sls-slp] Call for Use Cases of Space Packet Protocol

[Shames, Peter M (312B)]

Hi Jonathan,

I think you missed my point.  There are existing SPP secondary header formats that are already in use.  The ESA has PUS, the CCSDS MAL has theirs (not in wide use, but defined), and JPL has "standard" ways of using the SPP secondary header to transmit time codes.  This last is a sort of "CCSDS standard" in that it is recommended, but not required, in the SPP spec.


4.1.3.2.1.5  If present, the Packet Secondary Header shall consist of either:

a)      a Time Code Field (variable length) only;

b)      an Ancillary Data Field (variable length) only; or

c)      a Time Code Field followed by an Ancillary Data Field.

I believe you must accept this, and suggest that trying to change it at this point will doom you to failure.  There will surely be ESA feedback.

I will point out, however, that ESA effectively adopted option b) for the MAL SPP mapping, and that contains a "Version Number"  in the first field of the Secondary Header.  I have not looked to see if that is sufficiently general that it could be co-opted for this purpose.

Peter


From: SLS-SLP <sls-slp-bounces at mailman.ccsds.org> on behalf of Jonathan Wilmot via SLS-SLP <sls-slp at mailman.ccsds.org>
Reply-To: "Wilmot, Jonathan J. (GSFC-5820)" <Jonathan.J.Wilmot at NASA.gov>
Date: Thursday, February 28, 2019 at 8:00 AM
To: Peter Shames <Peter.M.Shames at jpl.nasa.gov>, Scott Burleigh <Scott.C.Burleigh at jpl.nasa.gov>, "Greenberg, Edward" <Edward.Greenberg at jpl.nasa.gov>, "sls-slp at mailman.ccsds.org" <sls-slp at mailman.ccsds.org>
Cc: Lee Pitts <robert.l.pitts at nasa.gov>
Subject: Re: [Sls-slp] Call for Use Cases of Space Packet Protocol

Peter,

   I understand that "managed" will be the initial approach similar to the compromise for spacecraft ID's being only unique within an assigned spectrum. Something we can do now is maybe have a version indication in the first byte(s) of the secondary header. And although I hate to say it, maybe even use an SDNV?

   Kind regards,

      Jonathan

On 2/28/2019 10:51 AM, Shames, Peter M (312B) wrote:
Hi Jonathan,

I get that you would like this, but that would mean changing all of the existing header structures that are already in wide use.  I think what we should do it to treat this like a "managed parameter" where you have to know which of the formats you are processing.

That said, for any new / future formats you could certainly include some sort of standard "secondary header type" flag, but for current ones I think you must accept the "managed" approach.  Otherwise this will never get off the ground.

Peter


From: SLS-SLP <sls-slp-bounces at mailman.ccsds.org><mailto:sls-slp-bounces at mailman.ccsds.org> on behalf of Jonathan Wilmot via SLS-SLP <sls-slp at mailman.ccsds.org><mailto:sls-slp at mailman.ccsds.org>
Reply-To: "Wilmot, Jonathan J. (GSFC-5820)" <Jonathan.J.Wilmot at NASA.gov><mailto:Jonathan.J.Wilmot at NASA.gov>
Date: Thursday, February 28, 2019 at 7:43 AM
To: Peter Shames <Peter.M.Shames at jpl.nasa.gov><mailto:Peter.M.Shames at jpl.nasa.gov>, Scott Burleigh <Scott.C.Burleigh at jpl.nasa.gov><mailto:Scott.C.Burleigh at jpl.nasa.gov>, "Greenberg, Edward" <Edward.Greenberg at jpl.nasa.gov><mailto:Edward.Greenberg at jpl.nasa.gov>, "sls-slp at mailman.ccsds.org"<mailto:sls-slp at mailman.ccsds.org> <sls-slp at mailman.ccsds.org><mailto:sls-slp at mailman.ccsds.org>
Cc: Lee Pitts <robert.l.pitts at nasa.gov><mailto:robert.l.pitts at nasa.gov>
Subject: Re: [Sls-slp] Call for Use Cases of Space Packet Protocol

Peter,

    If we have agreement I will start rapidly moving in that direction. The schema will be the SOIS EDS and SOIS DoT.  For true interoperability I think we need something in the headers that indicate which one of the secondary headers is being used so it can be parsed at run-time.

   Kind regards,

        Jonathan

On 2/28/2019 10:36 AM, Shames, Peter M (312B) wrote:
Hi Jonathan,

If there is a DEM to SPP mapping that uses the standard SPP headers and adds the DEM as a packet secondary header that would be entirely suitable.

I'd like to encourage something like a two level approach to this:

1.       A registry for each SPP secondary header that is registered, with org, contact person, name of the project, and a pointer to the documentation

2.       An XML schema (or JSON, your choice) that formalizes the secondary header structure, field names, data types, sizes, and definitions

That way people can look it up, understand it, know where to find more info, etc.  And, as I suggested, using the DoT would lend a certain regularity to the typing of the data.

Does his make sense to you guys?

Thanks, Peter


From: SLS-SLP <sls-slp-bounces at mailman.ccsds.org><mailto:sls-slp-bounces at mailman.ccsds.org> on behalf of Jonathan Wilmot via SLS-SLP <sls-slp at mailman.ccsds.org><mailto:sls-slp at mailman.ccsds.org>
Reply-To: "Wilmot, Jonathan J. (GSFC-5820)" <Jonathan.J.Wilmot at NASA.gov><mailto:Jonathan.J.Wilmot at NASA.gov>
Date: Thursday, February 28, 2019 at 7:28 AM
To: Peter Shames <Peter.M.Shames at jpl.nasa.gov><mailto:Peter.M.Shames at jpl.nasa.gov>, Scott Burleigh <Scott.C.Burleigh at jpl.nasa.gov><mailto:Scott.C.Burleigh at jpl.nasa.gov>, "Greenberg, Edward" <Edward.Greenberg at jpl.nasa.gov><mailto:Edward.Greenberg at jpl.nasa.gov>, "sls-slp at mailman.ccsds.org"<mailto:sls-slp at mailman.ccsds.org> <sls-slp at mailman.ccsds.org><mailto:sls-slp at mailman.ccsds.org>
Cc: Lee Pitts <robert.l.pitts at nasa.gov><mailto:robert.l.pitts at nasa.gov>
Subject: Re: [Sls-slp] Call for Use Cases of Space Packet Protocol

Peter and folks

     I agree with Peter's approach and would welcome moving forward with this. Hopefully  before the missions finalize their implementation.

   As I remember, the DEM did not adopt the SPP format but they did contain the same type of meta data that ECSS-PUS and the SPP proposal contain.  The mapping between the Orion DEM and the SPP proposal format has been done and is in use at JSC for the LOP-G prototyping efforts.

  Kind regards,

    Jonathan

On 2/28/2019 10:14 AM, Shames, Peter M (312B) wrote:
Folks,

What we have proposed in the SPP revision is to create a SANA registry for local, agency, or even multi-agency packet secondary headers.  This could include PUS, MAL packet mapping, Jonathan's LOP-G headers, and others.  There is a proposal for a simple registry structure in the draft SPP doc that would allow all of these to be registered.  I suggest that you look at this and propose any needed metadata for the registry.  You could try and engage in some sort of "normalization" effort for the field names, structures, and contents, or at least try and do some sort of evaluation of the kinds of data and the different ways they are named and represented.  I'll bet you will find that they are all over the map.

By the way, the SOIS Dictionary of Terms (DoT) may prove to be useful as a source of standardized terms.

Lastly, as I recall the Constellation DEM did not adhere to the SPP at all.  I may be mis-remembering.

Cheers, Peter


From: SLS-SLP <sls-slp-bounces at mailman.ccsds.org><mailto:sls-slp-bounces at mailman.ccsds.org> on behalf of Jonathan Wilmot via SLS-SLP <sls-slp at mailman.ccsds.org><mailto:sls-slp at mailman.ccsds.org>
Reply-To: "Wilmot, Jonathan J. (GSFC-5820)" <Jonathan.J.Wilmot at NASA.gov><mailto:Jonathan.J.Wilmot at NASA.gov>
Date: Thursday, February 28, 2019 at 7:03 AM
To: Scott Burleigh <Scott.C.Burleigh at jpl.nasa.gov><mailto:Scott.C.Burleigh at jpl.nasa.gov>, "Greenberg, Edward" <Edward.Greenberg at jpl.nasa.gov><mailto:Edward.Greenberg at jpl.nasa.gov>, "sls-slp at mailman.ccsds.org"<mailto:sls-slp at mailman.ccsds.org> <sls-slp at mailman.ccsds.org><mailto:sls-slp at mailman.ccsds.org>
Cc: Peter Shames <Peter.M.Shames at jpl.nasa.gov><mailto:Peter.M.Shames at jpl.nasa.gov>, Lee Pitts <robert.l.pitts at nasa.gov><mailto:robert.l.pitts at nasa.gov>
Subject: Re: [Sls-slp] Call for Use Cases of Space Packet Protocol

Ed, Scott,

   The CCSDS Space Packet is being used at NASA, ESA and CAST as end user application command and telemetry message. It contains information in the primary and secondary headers to allow end user applications to identify the data content and format, and also allow mission architecture specific lower layers to transport user application data within a subnetworks or across networks.

   As part of this discussion I would like to re-submit a proposal to create a secondary header that could be included as an optional header in the SPP Blue book or registered in SANA as a standard SPP secondary header type. (ECSS-PUS headers should also be registered)

Note:  The LOP-G program,  and other missions at  JSC, GSFC, and ARC,  are  currently using the format in the attached proposal.  This is an opportunity for CCSDS to  improve mission interoperability by supporting the SPP uses cases that missions require.

  Kind Regards,

      Jonathan

Jonathan Wilmot
NASA/GSFC
CCSDS SOIS Area Director

On 4/22/2018 12:16 PM, Burleigh, Scott C (312B) wrote:
Ed, I think of the Space Packet as being the thing that the old Constellation project called a Data Exchange Message (DEM).  I think it performs the same function in the stack, and I suspect that it could easily carry all the same metadata that the DEM was supposed to carry.

Scott

From: Greenberg, Edward (312B)
Sent: Sunday, April 22, 2018 7:37 AM
To: sls-slp at mailman.ccsds.org<mailto:sls-slp at mailman.ccsds.org>; Jonathan.J.Wilmot at NASA.gov<mailto:Jonathan.J.Wilmot at NASA.gov>
Cc: Lee Pitts <robert.l.pitts at nasa.gov><mailto:robert.l.pitts at nasa.gov>
Subject: Call for Use Cases of Space Packet Protocol

There seems to be lots of new Use Cases for Space Packets then were considered in the original specification. For example:
·         ESA has PUS
·         Space Station has its own secondary header
·         Orion is looking for a secondary header
Originally the Space Packet was an envelope for data transferred over single link (includes tunneling), now the packet is being looked at for network data transfer, local onboard data transfer (including measurement broadcasting).
It is possible that the role of the packet might change with the use of DTN bundles.
Just to take the broadest view: We currently have two forms of packets, should there be more or should even these be examined to determine if they should be blended  into a new packet design.
Can we get each of you to send in your present and possibly desired Use Cases for our beloved Space Packet so that we could determine its future.








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