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<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Dear SDLS WG members,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">I have lately received a few (internal NASA) questions regarding the order of processing between SDLS and COP, similar to discussions in the WG earlier. Since we already discussed adding clarifying
text in the next SDLS Green Book revision, attached is a diagram I created to illustrate the flow and interactions between protocol sub-layers. If the WG finds this helpful, we could consider it (or something similar) for inclusion along with the clarifying
text.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height:105%"><b><span style="font-size:11.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#545761">Craig Biggerstaff<o:p></o:p></span></b></p>
<p class="MsoNormal" style="line-height:105%"><span style="font-size:11.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height:105%"><span style="font-size:11.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#1F497D"><img width="86" height="48" style="width:.9in;height:.5in" id="_x0000_i1027" src="cid:image003.jpg@01D741C1.4D51F7B0" alt="KBR - Copy"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:105%"><span style="font-size:9.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#545761">KBR | Senior Engineer Specialist, Mission Systems Operations Contract<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:105%"><span style="font-size:9.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#545761">2101 NASA Parkway, Mail Code CD4 | Houston, Texas 77058 | USA<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:105%"><span style="font-size:9.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#545761">Office: +1 281.483.2027 |
<a href="mailto:craig.biggerstaff@nasa.gov">craig.biggerstaff@nasa.gov</a></span><span style="font-size:9.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal" align="center" style="text-align:center;line-height:105%"><span style="font-family:"Times New Roman",serif;color:#1F497D"><o:p> </o:p></span></p>
<div class="MsoNormal" align="center" style="text-align:center;line-height:105%">
<span style="font-family:"Times New Roman",serif;color:#1F497D">
<hr size="4" width="100%" align="center">
</span></div>
<p class="MsoNormal" style="line-height:105%"><span style="font-size:8.0pt;line-height:105%;font-family:"Arial",sans-serif;color:#545761">This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the
intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete
all copies of this message.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt">From:</span></b><span style="font-size:11.0pt"> SLS-SEA-DLS <sls-sea-dls-bounces@mailman.ccsds.org>
<b>On Behalf Of </b>Moury Gilles<br>
<b>Sent:</b> Friday, February 5, 2021 11:44 AM<br>
<b>To:</b> sls-sea-dls@mailman.ccsds.org<br>
<b>Subject:</b> [EXTERNAL] [Sls-sea-dls] TR: CCSDS Order of Processing: Figure 6-3 in CCSDS 232.0 and Figure 3-3 in CCSDS 350.5-G<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="FR" style="font-size:11.0pt;color:#1F497D">Dear SDLS WG member,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="FR" style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">The order of processing between SDLS and the COP in TC has raised questions by implementing projects. To clarify the matter and provide a complete justification, Greg Kazz (SLP WG chairman) proposes
to include an additional paragraph in the SDLS Green Book (355.0-G) (see exchange of mails hereafter). A text along the following lines is proposed to be inserted in front of Figure 3-3 on page 3-10:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">“There are several reasons for this ordering of SDLS and COP functions :</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoNormal" style="mso-list:l0 level1 lfo3"><span style="font-size:11.0pt;color:#1F497D">COP-1, being a go-back-N retransmission protocol, will eventually replay TC frames. SDLS is a function providing anti-replay protection, integrity and confidentiality.
Therefore if FOP is applied before SDLS at the sending end, and SDLS before FARM at the receiving end, SDLS at the receiving end will discard all replayed frames by COP-1, thus defeating the COP.</span><o:p></o:p></li><li class="MsoNormal" style="mso-list:l0 level1 lfo3"><span style="font-size:11.0pt;color:#1F497D">SDLS at the receiving end checks integrity of TC frames by checking the MAC. The MAC is a very powerful error detecting code (in fact much more powerful than
the BCH code). Therefore, SDLS receiving end will discard all TC frames impacted by transmission errors, if the FARM is applied after SDLS. This has two impacts :</span>
<o:p></o:p></li><ul style="margin-top:0in" type="circle">
<li class="MsoNormal" style="mso-list:l0 level2 lfo3"><span style="font-size:11.0pt;color:#1F497D">Accountability of transmission errors vs security related events cannot be made : all errors are detected by SDLS and therefore classified as security events</span><o:p></o:p></li><li class="MsoNormal" style="mso-list:l0 level2 lfo3"><span style="font-size:11.0pt;color:#1F497D">COP-1 will replay those SDLS rejected frames, because the FARM will never see them. Those replayed TC frames will be later rejected as replay by SDLS.”</span><o:p></o:p></li></ul>
</ul>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">SDLS GB (355.0-G-1) is due for 5-year review in 2023. Nevertheless, GB do not have the same stability requirement as Blue Book and could possibly be updated more frequently. The proposal I would
like to submit to the WG is to prepare an update of the GB this year to include this justification and any other clarifications/additions/updates that might be beneficial. Of course the proposed text is to be discussed and tuned so that it fits properly in
that section.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Please do not hesitate to comment on that proposal so that we can initiate or not this GB update.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Gilles Moury<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">SDLS WG chair<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="FR" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Gilles MOURY</span><span lang="FR" style="font-family:"Times New Roman",serif;color:#1F497D">
<br>
</span><span lang="FR" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">CNES Toulouse</span><span lang="FR" style="font-family:"Times New Roman",serif;color:#1F497D">
</span><span lang="FR" style="font-size:11.0pt;color:#1F497D"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="FR" style="font-size:11.0pt">De :</span></b><span lang="FR" style="font-size:11.0pt"> Kazz, Greg J (US 312B) <<a href="mailto:greg.j.kazz@jpl.nasa.gov">greg.j.kazz@jpl.nasa.gov</a>>
<br>
<b>Envoyé :</b> jeudi 21 janvier 2021 18:12<br>
<b>À :</b> Biggerstaff, Craig (JSC-CD42)[SGT, INC] <<a href="mailto:craig.biggerstaff@nasa.gov">craig.biggerstaff@nasa.gov</a>>; Moury Gilles <<a href="mailto:Gilles.Moury@cnes.fr">Gilles.Moury@cnes.fr</a>>; Weiss, Howard <<a href="mailto:Howard.Weiss@parsons.com">Howard.Weiss@parsons.com</a>>;
<a href="mailto:Gian.Paolo.Calzolari@esa.int">Gian.Paolo.Calzolari@esa.int</a><br>
<b>Cc :</b> Shames, Peter M (US 312B) <<a href="mailto:peter.m.shames@jpl.nasa.gov">peter.m.shames@jpl.nasa.gov</a>>; Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <<a href="mailto:victor.j.sank@nasa.gov">victor.j.sank@nasa.gov</a>>; Andres,
Brent (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <<a href="mailto:brent.r.andres@nasa.gov">brent.r.andres@nasa.gov</a>>; Matthew Cosby <<a href="mailto:Matt.Cosby@Goonhilly.org">Matt.Cosby@Goonhilly.org</a>>; Thomas Gannett <<a href="mailto:thomas.gannett@tgannett.net">thomas.gannett@tgannett.net</a>><br>
<b>Objet :</b> Re: CCSDS Order of Processing: Figure 6-3 in CCSDS 232.0 and Figure 3-3 in CCSDS 350.5-G<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="FR"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">That would be in 2023, 3 years from now…since security is on everybody’s plate these days, I highly recommend it get updated this year. It is a Green book, so I would hope we have more discretion and flexibility
in updating them more frequently than the blue books. I understand the rationale for not updating blue books that often.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Thanks!<br>
Greg<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="color:black">From: </span></b><span style="color:black">"Biggerstaff, Craig (JSC-CD42)[SGT, INC]" <<a href="mailto:craig.biggerstaff@nasa.gov">craig.biggerstaff@nasa.gov</a>><br>
<b>Date: </b>Thursday, January 21, 2021 at 8:53 AM<br>
<b>To: </b>"Kazz, Greg J (US 312B)" <<a href="mailto:greg.j.kazz@jpl.nasa.gov">greg.j.kazz@jpl.nasa.gov</a>>, Moury Gilles <<a href="mailto:Gilles.Moury@cnes.fr">Gilles.Moury@cnes.fr</a>>, "Weiss, Howard" <<a href="mailto:Howard.Weiss@parsons.com">Howard.Weiss@parsons.com</a>><br>
<b>Cc: </b>"Shames, Peter M (US 312B)" <<a href="mailto:peter.m.shames@jpl.nasa.gov">peter.m.shames@jpl.nasa.gov</a>>, "<a href="mailto:Gian.Paolo.Calzolari@esa.int">Gian.Paolo.Calzolari@esa.int</a>" <<a href="mailto:Gian.Paolo.Calzolari@esa.int">Gian.Paolo.Calzolari@esa.int</a>>,
"Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC]" <<a href="mailto:victor.j.sank@nasa.gov">victor.j.sank@nasa.gov</a>>, "Andres, Brent (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC]" <<a href="mailto:brent.r.andres@nasa.gov">brent.r.andres@nasa.gov</a>>,
Matthew Cosby <<a href="mailto:Matt.Cosby@Goonhilly.org">Matt.Cosby@Goonhilly.org</a>>, Thomas Gannett <<a href="mailto:thomas.gannett@tgannett.net">thomas.gannett@tgannett.net</a>><br>
<b>Subject: </b>RE: CCSDS Order of Processing: Figure 6-3 in CCSDS 232.0 and Figure 3-3 in CCSDS 350.5-G<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">I agree with incorporating Gilles’ text. The normal opportunity to do this would be the Green Book’s 5-year review/revision cycle.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Best regards,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Craig</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt">From:</span></b><span style="font-size:11.0pt"> Kazz, Greg J (US 312B) <<a href="mailto:greg.j.kazz@jpl.nasa.gov">greg.j.kazz@jpl.nasa.gov</a>>
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<b>Sent:</b> Wednesday, January 20, 2021 6:15 PM<br>
<b>To:</b> Moury Gilles <<a href="mailto:Gilles.Moury@cnes.fr">Gilles.Moury@cnes.fr</a>>; Biggerstaff, Craig (JSC-CD42)[SGT, INC] <<a href="mailto:craig.biggerstaff@nasa.gov">craig.biggerstaff@nasa.gov</a>>; Weiss, Howard <<a href="mailto:Howard.Weiss@parsons.com">Howard.Weiss@parsons.com</a>><br>
<b>Cc:</b> Shames, Peter M (JPL-312B)[JPL Employee] <<a href="mailto:peter.m.shames@jpl.nasa.gov">peter.m.shames@jpl.nasa.gov</a>>;
<a href="mailto:Gian.Paolo.Calzolari@esa.int">Gian.Paolo.Calzolari@esa.int</a>; Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <<a href="mailto:victor.j.sank@nasa.gov">victor.j.sank@nasa.gov</a>>; Andres, Brent (GSFC-567.0)[SCIENCE SYSTEMS
AND APPLICATIONS INC] <<a href="mailto:brent.r.andres@nasa.gov">brent.r.andres@nasa.gov</a>>; Matthew Cosby <<a href="mailto:Matt.Cosby@Goonhilly.org">Matt.Cosby@Goonhilly.org</a>>; Thomas Gannett <<a href="mailto:thomas.gannett@tgannett.net">thomas.gannett@tgannett.net</a>><br>
<b>Subject:</b> CCSDS Order of Processing: Figure 6-3 in CCSDS 232.0 and Figure 3-3 in CCSDS 350.5-G</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Gilles, Craig, and Howie,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt">What Gilles provided me, Victor, and Brent (highlighted below, i.e., his bullet points) was an excellent explanation, as to why the COP has to be applied
<i>after</i> SDLS at the sending end. And because this topic seems to come up again and again at least at NASA and perhaps at other agencies as well, I strongly recommend that we take Gilles’ text below and put it into a new paragraph in front of figure 3-3
on p. 3-10 in CCSDS 350.5-G (June 2018) to augment the rationale for that figure. I believe it will be useful for user’s to understand the rationale for processing between COP and SDLS. Note that figure 3-3 is identical to figure 6-3 in CCSDS 232.0.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt">What does the SDLS WG think of this recommendation ?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Best regards,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Greg</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="color:black">From: </span></b><span style="color:black">Moury Gilles <<a href="mailto:Gilles.Moury@cnes.fr">Gilles.Moury@cnes.fr</a>><br>
<b>Date: </b>Tuesday, January 12, 2021 at 3:57 AM<br>
<b>To: </b>"Kazz, Greg J (US 312B)" <<a href="mailto:greg.j.kazz@jpl.nasa.gov">greg.j.kazz@jpl.nasa.gov</a>><br>
<b>Cc: </b>"Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC]" <<a href="mailto:victor.j.sank@nasa.gov">victor.j.sank@nasa.gov</a>><br>
<b>Subject: </b>[EXTERNAL] RE: CCSDS Order of Processing: Figure 6-3 in CCSDS 232.0</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Dear Greg and Victor,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">All my best wishes for 2021 ! I hope we can meet in person this year !</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">There are several reasons for this ordering of SDLS and COP functions :</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoNormal" style="mso-list:l0 level1 lfo3"><span style="font-size:11.0pt;color:#1F497D;background:yellow;mso-highlight:yellow">COP-1, being a go-back-N retransmission protocol, will eventually replay TC frames. SDLS is a function providing anti-replay
protection, integrity and confidentiality. Therefore if FOP is applied before SDLS at the sending end, and SDLS before FARM at the receiving end, SDLS at the receiving end will discard all replayed frames by COP-1, thus defeating the COP.</span><o:p></o:p></li><li class="MsoNormal" style="mso-list:l0 level1 lfo3"><span style="font-size:11.0pt;color:#1F497D;background:yellow;mso-highlight:yellow">SDLS at the receiving end checks integrity of TC frames by checking the MAC. The MAC is a very powerful error detecting
code (in fact much more powerful than the BCH code). Therefore, SDLS receiving end will discard all TC frames impacted by transmission errors, if the FARM is applied after SDLS. This has two impacts :</span>
<o:p></o:p></li><ul style="margin-top:0in" type="circle">
<li class="MsoNormal" style="mso-list:l0 level2 lfo3"><span style="font-size:11.0pt;color:#1F497D;background:yellow;mso-highlight:yellow">Accountability of transmission errors vs security related events cannot be made : all errors are detected by SDLS and therefore
classified as security events</span><o:p></o:p></li><li class="MsoNormal" style="mso-list:l0 level2 lfo3"><span style="font-size:11.0pt;color:#1F497D;background:yellow;mso-highlight:yellow">COP-1 will replay those SDLS rejected frames, because the FARM will never see them. Those replayed TC frames will be later
rejected as replay by SDLS.</span><o:p></o:p></li></ul>
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<p class="MsoListParagraph"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:0in"><span style="font-size:11.0pt;color:#1F497D">I hope this clarifies the matter.</span><o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:0in"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:0in"><span style="font-size:11.0pt;color:#1F497D">Best regards,</span><o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:0in"><span style="font-size:11.0pt;color:#1F497D">Gilles</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Gilles MOURY</span><span style="font-family:"Times New Roman",serif;color:#1F497D">
<br>
</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">CNES Toulouse</span><span style="font-family:"Times New Roman",serif;color:#1F497D">
</span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt">De :</span></b><span style="font-size:11.0pt"> Kazz, Greg J (US 312B) <<a href="mailto:greg.j.kazz@jpl.nasa.gov">greg.j.kazz@jpl.nasa.gov</a>>
<br>
<b>Envoyé :</b> dimanche 10 janvier 2021 18:52<br>
<b>À :</b> Moury Gilles <<a href="mailto:Gilles.Moury@cnes.fr">Gilles.Moury@cnes.fr</a>><br>
<b>Cc :</b> Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <<a href="mailto:victor.j.sank@nasa.gov">victor.j.sank@nasa.gov</a>><br>
<b>Objet :</b> CCSDS Order of Processing: Figure 6-3 in CCSDS 232.0</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Happy New Year, Gilles !<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Victor Sank and I have a question for you, which I would like to ask you again to confirm my understanding, or correct my thinking.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Why must the FOP on the ground be done after SDLS is applied ? In other words, “why can’t the Frame Sequence Number in the Transfer Frame Primary Header, be input/applied prior to the SDSL ApplySecurity? “ <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">I vaguely remember you saying something like, if the order were reversed (do FOP first, and then SDLS), there would be no way to know why a transfer frame was rejected and therefore the project would not have the accountability it needs
to take the correct action. There would be <i>no definitive</i> accountability as to
<i>why </i>a given<i> </i>transfer frames was rejected i.e., was it first rejected by SDLS because of an intentional cyber attack or was it just a non-cyber related incident detected by SDLS security (e.g., bit flips due to a regular noisy channel). By executing
the FOP-1 and the FARM-1 together as a pair, i.e., back to back as Figure 6-3 shows, you get clean accountability back from SDLS and also from the FARM (if the frame passes SDLS, then the FARM can determine if any other COP rules have been violated or not,
independent of SDLS). <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Is my explanation above also your understanding ?<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Best regards,<o:p></o:p></p>
<p class="MsoNormal">Greg<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Greg Kazz</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Principal Engineer</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Technical Group Supervisor,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">PSSE/EEISE/PPSE (312B)</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Jet Propulsion Laboratory<img border="0" width="1366" height="892" style="width:14.225in;height:9.2916in" id="Picture_x0020_1" src="cid:image004.png@01D741BE.FB886290"></span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">4800 Oak Grove Dr., M/S 301-490</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">Pasadena, CA 91109</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">1+(818)393 6529(voice)</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">1</span><span lang="ES-MX" style="font-size:11.0pt">+(818)393 6871(fax)</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">email: <a href="mailto:greg.j.kazz@jpl.nasa.gov">
greg.j.kazz@jpl.nasa.gov</a> </span><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
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