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

Gian.Paolo.Calzolari at esa.int Gian.Paolo.Calzolari at esa.int
Fri Mar 1 11:20:54 UTC 2019


Dear,
        after so many e-mail I would like to make the point of the 
situation (as far as I understand it) with the caveat that there shall be 
something wrong in this story as it looks that Peter and I agree on 
something.  :o)

The envisaged approach by Peter is that
A) The secondary header section is SPP will inform that a number of 
secondary-header-types are registered with SANA and the actual contents of 
the secondary header are (somehow) "managed" at SPP service user level 
(Note 1)
B) Secondary Header Types will be registered in SANA with a two level 
approach :
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 

Is this the common understanding for everybody?

Best regards and have a nice week end

Gian Paolo

Note1: In fact the service user of the SPP Packet Service provides the SPP 
service provider with a "pre cooked" space packet in the PACKET.request 
while the service user of the SPP Octet String Service provides the SPP 
service provider with a  "pre cooked" space packet data field and a 
Secondary Header Indicator in the OCTET_STRING.request



From:   "Shames, Peter M \(312B\) via SLS-SLP" <sls-slp at mailman.ccsds.org>
To:     Jonathan Wilmot <Jonathan.J.Wilmot at NASA.gov>, "Burleigh, Scott C 
(312B)" <Scott.C.Burleigh at jpl.nasa.gov>, "Greenberg, Edward (312B)" 
<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>
Date:   28-02-19 17:13
Subject:        Re: [Sls-slp] Call for Use Cases of Space Packet Protocol
Sent by:        "SLS-SLP" <sls-slp-bounces at mailman.ccsds.org>



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> 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 7:43 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,

    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> 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 7:28 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 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> 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 7:03 AM
To: 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: Peter Shames <Peter.M.Shames at jpl.nasa.gov>, Lee Pitts 
<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; Jonathan.J.Wilmot at NASA.gov
Cc: Lee Pitts <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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