[Sls-slp] LFSR OID frame RIDs affecting USLP, TM, AOS SDLPs

Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] victor.j.sank at nasa.gov
Fri May 21 15:57:07 UTC 2021

In order to make some attempt to standardize the LFSRs and their associated polynomial  in CCSDS, I would suggest that we use a standard for cell labeling that makes a simple association with the polynomial as in MatLab.  If you don’t like the MatLab convention, pick something and lets make it a standard for the NASA documents.  Eventually maybe we can get CCSDS to accept the standard.
              They are a standards organization aren’t they?

From: Kazz, Greg J (US 312B) <greg.j.kazz at jpl.nasa.gov>
Sent: Friday, May 21, 2021 11:31 AM
To: Andrews, Kenneth S (JPL-332B)[JPL Employee] <kenneth.s.andrews at jpl.nasa.gov>
Cc: Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <victor.j.sank at nasa.gov>; Kazz, Greg J (US 312B) via SLS-SLP <sls-slp at mailman.ccsds.org>; Andrea Modenini (external) <Andrea.Modenini at esa.int>
Subject: LFSR OID frame RIDs affecting USLP, TM, AOS SDLPs

Hi Ken,

The SLP WG decided to put both of your diagrams into a new non-normative annex in USLP, TM, and AOS.
The text in the normative part of the link layer books will state:

The TFDZ of an OID Transfer Frame shall be generated by use of a 32-cell Linear Feedback Shift Register (LFSR) with polynomial 1 + D + D2 + D22 +D32, see Annex X.

Where Annex X is TBD and will be added by me to the document.

We have some questions and requests for you:

  1.  Why does the initialization data differ from one figure to the other one?
  2.  The ‘1’ in the figures are misleading to some WG members, please replace ‘1’ with D sub zero i.e., D0 in the figures.
  3.  Consensus of WG was to specify the initialization vector in both of the diagrams

New Info:

Do you concur with these changes ?
If so, the SLP WG will wait for your modifications to those diagrams and thereafter I will insert them into the AOS, USLP, and TM pink sheets.
When might we receive them ?

Best regards,

Greg Kazz
Principal Engineer
Technical Group Supervisor,
Jet Propulsion Laboratory
4800 Oak Grove Dr., M/S 301-490
Pasadena, CA 91109
1+(818)393 6529(voice)
1+(818)393 6871(fax)
email: greg.j.kazz at jpl.nasa.gov<mailto:greg.j.kazz at jpl.nasa.gov>

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