[Sls-sea-dls] FW: [EXTERNAL] RE: Extending the 1st Header Pointer in AOS to 16 bits to cover max Transfer Frame length

[Thomas Gannett]

Yes, forget the corrigendum and make all the changes via pink sheets.

On Wed, May 10, 2023 at 3:04 PM Kazz, Greg (US 312B) <
greg.j.kazz at jpl.nasa.gov> wrote:

> Hi Tom,
>
>
>
> We also have one more additional change to AOS, which will require a new
> version 5 of AOS SDLP. This change was OKed by the SLP WG by polling last
> year, but I didn’t put it into the document pipeline, which is my bad.  So
> now, perhaps you don’t need to treat the Frame Header Error Control change
> in 4.1.2.6 as a Technical Corrigendum with change bars, but simply sweep
> that change along into this new Version 5 AOS book, since changing the
> First Header Pointer to 16 bits is clearly normative. Both SLP and C&S also
> concurred on this change as well.
>
>
>
> I have attached the change to the First Header Pointer field within the
> M_PDU header in the file attached in section 4.1.4.2.
>
>
>
> Please let me know if you have any questions about this. I will generate a
> resolution for the SLS area to enable this change.
>
>
>
> Thanks,
>
> Greg
>
>
>
> *From: *Moury Gilles <Gilles.Moury at cnes.fr>
> *Date: *Friday, May 13, 2022 at 8:13 AM
> *To: *"Kazz, Greg (US 312B)" <greg.j.kazz at jpl.nasa.gov>
> *Cc: *"Andrea.Modenini at esa.int" <Andrea.Modenini at esa.int>, "Sank, Victor
> J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC]" <
> victor.j.sank at nasa.gov>, "Rodriguez, Shannon (GSFC-5670)" <
> shannon.rodriguez-1 at nasa.gov>, Ignacio Aguilar-Sanchez <
> Ignacio.Aguilar.Sanchez at esa.int>
> *Subject: *[EXTERNAL] RE: Extending the 1st Header Pointer in AOS to 16
> bits to cover max Transfer Frame length
>
>
>
> Dear Greg,
>
> No objection to extending the AOS FHP field to 16-bit in order to extend
> AOS transfer frame maximum length to 65536 octets which is coherent with
> very high rate payload TM links (up to 1Gbps) which use AOS SDLP.
>
> Best regards,
>
> Gilles
>
>
>
> Gilles MOURY
> CNES Toulouse
>
> *De :* SLS-SLP <sls-slp-bounces at mailman.ccsds.org> *De la part de* Kazz,
> Greg (US 312B) via SLS-SLP
> *Envoyé :* mercredi 11 mai 2022 19:39
> *À :* Kazz, Greg (US 312B) via SLS-SLP <sls-slp at mailman.ccsds.org>
> *Cc :* Andrea.Modenini at esa.int; Sank, Victor J. (GSFC-567.0)[SCIENCE
> SYSTEMS AND APPLICATIONS INC] <victor.j.sank at nasa.gov>; Rodriguez,
> Shannon (GSFC-5670) <shannon.rodriguez-1 at nasa.gov>
> *Objet :* [Sls-slp] Extending the 1st Header Pointer in AOS to 16 bits to
> cover max Transfer Frame length
>
>
>
> Dear SLP WG,
>
>
>
> I’ve been asked by Andrea Modenini, the chair of the C&S WG, to poll you
> concerning their proposal below to utilize the 5 reserve bits in the M_PDU
> header of the AOS Transfer Frame in order to extend the 1st Header
> Pointer from 11 bits (2048 octet Maximum AOS Transfer Frame Size) to 16
> bits (65536 octet maximum AOS transfer frame). Note: USLP transfer frame
> maximum is also 65536 octets.
>
>
>
> Please provide me with your opinion by end of day May 17.
>
>
>
> Here is the proposal from Victor Sank and Shannon Rodriguez at NASA/GSFC:
>
>
>
> We agree that First Header Pointer must be able to point to first packet
> header that is in the Packet Zone of the transfer frame.  Even through the
> packets can be very long,  limited to a length of 65536 octets, and may
> cover several transfer frames, the problem is where in the frame the next
> packet starts.  The 11 bit first header pointer is the limitation since it
> would not be able to point far into the frame.  But there are 5 bits of
> reserved that can be used with the 11 bit, giving 16 total and covering
> what we need.
>
>               We would have to couple the extension of transfer frame
> lengths with making use of the reserved 5 bit in the M_PDU Header.  There
> is also an option that can be used.  If there is objection to extending the
> first header pointer to 16 bits, we could still allow longer transfer
> frames with the restriction that the packets used with these transfer
> frames are (temporarily) limited to 2048 octets.  In the future if/when
> CCSDS agrees to the 16 bit first header pointer, the restriction would be
> removed.
>
>
>
> CCSDS732.0-B-3 shows an M_PDU Header with the first header pointer as 11
> bits but also shows 5 bits of reserved.  If we use the 5 bit we have 16 and
> can point to 65536.
>
> [image: cid348906*image003.png at 01D86530.39956FC0]
>
>
>
> Best regards,
>
> Chair SLP WG
>
>
>
> Greg Kazz
>
> Principal Engineer
>
> Technical Group Supervisor,
>
> 312B Project Protection, Project Software, and End to End Information
> System Engineering
>
> Jet Propulsion Laboratory
>
> 4800 Oak Grove Dr
> <https://www.google.com/maps/search/4800+Oak+Grove+Dr?entry=gmail&source=g>.,
> 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
>
>
>
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