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<p>The graceful deprecation is a promising idea. In addition to
adding the "not recommended for new design" clause, it would be
helpful to specify the value and position of the virtual fill,
which could be set to match what the EU missions are currently
doing. I assume it is the same as the method in the 131.0-B-3 book
(all zeroes, at the beginning of the codeword), but it would be
good to clarify.<br>
</p>
<p> ----Jon</p>
<div class="moz-signature"><strong>Jon Hamkins</strong><br>
Chief Technologist, Communications, Tracking, and Radar Division<br>
<strong>O</strong> 818-354-4764 (preferred) | <strong>M</strong>
626-658-6220 (does not work at home)<br>
<br>
<strong>JPL</strong> | jpl.nasa.gov</div>
<div class="moz-cite-prefix">On 9/20/2021 8:59 AM, <a
class="moz-txt-link-abbreviated"
href="mailto:Marco.Rovatti@esa.int" moz-do-not-send="true">Marco.Rovatti@esa.int</a>
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:27896_1632153561_6148AFD9_27896_677_1_OFC118F592.F871883E-ONC1258756.003EC241-C1258756.0057D420@esa.int">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<span style=" font-size:10pt;font-family:sans-serif">Dear Andrea,
</span> <br>
<br>
<span style=" font-size:10pt;font-family:sans-serif">All the
reasons identified by Victor's e-mail below, provide a fair
rational for deletion of the Frame Header Error Control field
from the AOS Standard, except the misuse, which cannot be
charged on AOS's bill. </span> <br>
<span style=" font-size:10pt;font-family:sans-serif">The
additional overhead it's also of a lesser concern, since it s
only around 0.1%.</span> <br>
<span style=" font-size:10pt;font-family:sans-serif">In any case,
we have currently several missions in EU that use the AOS
including FHEC field, and more are in the pipeline (e.g. the six
Copernicus Expansion Missions) with the same frame format
configuration. </span> <br>
<span style=" font-size:10pt;font-family:sans-serif">Therefore, as
a first reaction, I would not be in favour of removing the FHEC
field from the AOS book, since by doing this we would make the
new missions non-compliant. </span> <br>
<span style=" font-size:10pt;font-family:sans-serif">Moreover, the
FHEC field is optional, each mission who does not need it, can
opt-out. In this respect, the standard is already providing
sufficient flexibility. </span> <br>
<span style=" font-size:10pt;font-family:sans-serif">So, all in
all, while I see some advantages in removing the FHEC I also see
an equal amount of benefits leaving it in the book. </span> <br>
<br>
<span style=" font-size:10pt;font-family:sans-serif">Nevertheless,
I will survey internally, both on-board and on-ground teams in
ESA to gather an Agency's view averaged across different
departments. </span> <br>
<span style=" font-size:10pt;font-family:sans-serif">I'll let you
know soon. </span> <br>
<br>
<span style=" font-size:10pt;font-family:sans-serif">In any case,
message to SLS-SLP, even if the final decision were to remove
it, I would do it "gracefully". </span> <br>
<span style=" font-size:10pt;font-family:sans-serif">We could in
principle find a way to indicate kind of "not recommended for
new design" clause/note in the next version of 732.0 book and in
5 or 10 years (i.e. one or two review cycles) we will eventually
remove it. </span> <br>
<br>
<span style=" font-size:10pt;font-family:sans-serif">Cheers</span>
<br>
<span style=" font-size:10pt;font-family:sans-serif">Marco </span>
<br>
<br>
<span style=" font-size:10pt;font-family:sans-serif"> </span> <br>
<br>
<br>
<br>
<br>
<span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">From:
</span><span style="
font-size:9pt;font-family:sans-serif"><a
class="moz-txt-link-abbreviated"
href="mailto:Andrea.Modenini@esa.int" moz-do-not-send="true">Andrea.Modenini@esa.int</a></span>
<br>
<span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">To:
</span><span style="
font-size:9pt;font-family:sans-serif">"Space Link Coding &
Synchronization Working Group" <a class="moz-txt-link-rfc2396E"
href="mailto:sls-cc@mailman.ccsds.org" moz-do-not-send="true"><sls-cc@mailman.ccsds.org></a></span>
<br>
<span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Cc:
</span><span style="
font-size:9pt;font-family:sans-serif">"Greg Kazz" <a
class="moz-txt-link-rfc2396E"
href="mailto:Greg.J.Kazz@jpl.nasa.gov" moz-do-not-send="true"><Greg.J.Kazz@jpl.nasa.gov></a>,
"Matthew Cosby" <a class="moz-txt-link-rfc2396E"
href="mailto:Matt.Cosby@Goonhilly.org" moz-do-not-send="true"><Matt.Cosby@Goonhilly.org></a></span>
<br>
<span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Date:
</span><span style="
font-size:9pt;font-family:sans-serif">17/09/2021 11:41</span> <br>
<span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Subject:
</span><span style="
font-size:9pt;font-family:sans-serif">[SLS-CC] Fw: CCSDS 732
section 4.1.2.6 Header Error Control</span> <br>
<span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Sent
by: </span><span style="
font-size:9pt;font-family:sans-serif">"SLS-CC" <a
class="moz-txt-link-rfc2396E"
href="mailto:sls-cc-bounces@mailman.ccsds.org"
moz-do-not-send="true"><sls-cc-bounces@mailman.ccsds.org></a></span>
<br>
<hr noshade="noshade"> <br>
<br>
<br>
<span style=" font-size:10pt;font-family:sans-serif">Dear all,</span><span
style=" font-size:12pt"> </span><span style="
font-size:10pt;font-family:sans-serif"><br>
JPL and GSFC brought to my attention that CCSDS 732, Section
4.1.2.6, specifies a shortened RS code that was originally meant
for uncoded or convolutional only coded telemetry links.</span><span
style=" font-size:12pt"> <br>
</span><span style=" font-size:10pt;font-family:sans-serif"><br>
However (see Victor's email below) it was found that this
specification was often misused, just becoming an additional
overhead for the link. Additionally, the specification itself
appears incomplete, leaving ambiguities to its actual
implementation.</span><span style=" font-size:12pt"> </span><span
style=" font-size:10pt;font-family:sans-serif"><br>
For this reason, JPL and GSFC are proposing to eliminate it.</span><span
style=" font-size:12pt"> <br>
</span><span style=" font-size:10pt;font-family:sans-serif"><br>
Could you please pool your Agencies, and let me know your
position <u>no later than 1st October 2021</u>? <br>
So that C&S WG can then formalise its position to SLP before
next Fall Meeting.</span><span style=" font-size:12pt"> </span><span
style=" font-size:10pt;font-family:sans-serif"><br>
</span><span style=" font-size:12pt"> <br>
</span><span style=" font-size:10pt;font-family:sans-serif"><br>
Kind Regards</span><span style=" font-size:12pt"> <br>
<br>
</span><span style="
font-size:8pt;color:#808080;font-family:Verdana"><b><br>
ESA - European Space Agency</b></span><span style="
font-size:12pt"> </span><span style="
font-size:8pt;color:#00a1e0;font-family:Verdana"><b><br>
Ph.D. Andrea Modenini</b></span><span style="
font-size:8pt;color:#808080;font-family:Verdana"><b><br>
TT&C Communications Systems Engineer</b></span><span
style=" font-size:12pt"><b> </b></span><span style="
font-size:8pt;color:#808080;font-family:Verdana"><br>
TT&C and PDT Systems & Techniques Section (TEC-EST)<br>
RF Systems Division<b><br>
ESTEC</b><br>
Keplerlaan 1, PO Box 299<br>
NL-2200 AG Noordwijk, The Netherlands<br>
<a class="moz-txt-link-abbreviated"
href="mailto:andrea.modenini@esa.int" moz-do-not-send="true">andrea.modenini@esa.int</a>
| </span><a
href="https://urldefense.us/v3/__http://www.esa.int/__;!!PvBDto6Hs4WbVuu7!bNqPG5_9INpete3Q1dj8WlabQwEnJTyFyg0Pe_YmsV5NkjzssPr878pouZTp6dgrsRJFoHQ$"
moz-do-not-send="true"><span style="
font-size:8pt;color:#8f8f8f;font-family:Verdana"><u>www.esa.int</u></span></a><span
style=" font-size:8pt;color:#808080;font-family:Verdana"><br>
T +31 71 56 53439, M +31 6 484 56 527</span><span style="
font-size:12pt"> </span><span style="
font-size:9pt;color:#800080;font-family:sans-serif"><br>
----- Forwarded by Andrea Modenini/estec/ESA on 17-09-21 10:35
-----</span><span style=" font-size:12pt"> <br>
</span><span style="
font-size:9pt;color:#5f5f5f;font-family:sans-serif"><br>
From: </span><span style="
font-size:9pt;font-family:sans-serif">"Sank, Victor J.
(GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC]" <a
class="moz-txt-link-rfc2396E"
href="mailto:victor.j.sank@nasa.gov" moz-do-not-send="true"><victor.j.sank@nasa.gov></a></span><span
style=" font-size:12pt"> </span><span style="
font-size:9pt;color:#5f5f5f;font-family:sans-serif"><br>
To: </span><span style="
font-size:9pt;font-family:sans-serif"><a
class="moz-txt-link-rfc2396E"
href="mailto:Andrea.Modenini@esa.int" moz-do-not-send="true">"Andrea.Modenini@esa.int"</a>
<a class="moz-txt-link-rfc2396E"
href="mailto:Andrea.Modenini@esa.int" moz-do-not-send="true"><Andrea.Modenini@esa.int></a></span><span
style=" font-size:12pt"> </span><span style="
font-size:9pt;color:#5f5f5f;font-family:sans-serif"><br>
Cc: </span><span style="
font-size:9pt;font-family:sans-serif">"Rodriguez, Shannon
(GSFC-5670)" <a class="moz-txt-link-rfc2396E"
href="mailto:shannon.rodriguez-1@nasa.gov"
moz-do-not-send="true"><shannon.rodriguez-1@nasa.gov></a>,
"Kazz, Greg J (JPL-312B)[JPL Employee]" <a
class="moz-txt-link-rfc2396E"
href="mailto:greg.j.kazz@jpl.nasa.gov" moz-do-not-send="true"><greg.j.kazz@jpl.nasa.gov></a>,
"Fong, Wai H. (GSFC-5670)" <a class="moz-txt-link-rfc2396E"
href="mailto:wai.h.fong@nasa.gov" moz-do-not-send="true"><wai.h.fong@nasa.gov></a>,
"Andrews, Kenneth S (JPL-332B)[JPL Employee]" <a
class="moz-txt-link-rfc2396E"
href="mailto:kenneth.s.andrews@jpl.nasa.gov"
moz-do-not-send="true"><kenneth.s.andrews@jpl.nasa.gov></a>,
"Hamkins, Jon (JPL-3300)[JPL Employee]" <a
class="moz-txt-link-rfc2396E"
href="mailto:jon.hamkins@jpl.nasa.gov" moz-do-not-send="true"><jon.hamkins@jpl.nasa.gov></a></span><span
style=" font-size:12pt"> </span><span style="
font-size:9pt;color:#5f5f5f;font-family:sans-serif"><br>
Date: </span><span style="
font-size:9pt;font-family:sans-serif">15-09-21 21:09</span><span
style=" font-size:12pt"> </span><span style="
font-size:9pt;color:#5f5f5f;font-family:sans-serif"><br>
Subject: </span><span style="
font-size:9pt;font-family:sans-serif">CCSDS 732 section 4.1.2.6
Header Error Control</span><span style=" font-size:12pt"> <br>
</span>
<hr noshade="noshade"><span style=" font-size:12pt"><br>
</span>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri">Andrea,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> There is a
shortened 15,11 RS code (q = 1 so shortened to 14,10) in the
CCSDS 732.0-B-3 book section 4.1.2.6 that is specified for use
in the transfer frame header that we believe is a hang over
from the days before the popular use of RS or other more
powerful block codes that get applied to the entire transfer
frame. It is intended for the case of convolution only code
or the case of no error correction code. We have had a few
missions miss use this code and were wondering if CCSDS should
remove it from the 732 book. You can see from the email from
Greg below that JPL has no missions that use this code and
over the last approximately 20 years, GSFC is only aware of it
being used where it was not intended. It is also odd that
this code is only specified in the 732 book and not the 131
books. </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> Being a
shortened code, I find the specification incomplete. As a
shortened code it is necessary to specify where the virtual
fill should go, at the beginning or at the end (or else ware).
In addition, it is not specified what value the virtual fill
nibble (4 bits) should be. Most common would be all zeros,
but it needs to be specified. Without these additional
details, a ground station receiver vendor would have to make
these parameters user selectable. The protection leaves out
the VCID count, it only covers the MCID, VCID and Signaling
Field. Seems to me an error in the VCID counter can make the
frame useless. Using this header code makes the primary
header 8 bytes long which I do not think is specified any
where else. </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> Your
thoughts please and if you agree, can you ask each C&S WG
member to poll their respective agency so at the next meeting
we can discuss the possibility of eliminating it from the
732.0 blue book? </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri">Thanks,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri">Victor</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"><b>From:</b> Kazz, Greg J
(US 312B) <</span><a href="mailto:greg.j.kazz@jpl.nasa.gov"
moz-do-not-send="true"><span style="
font-size:11pt;color:#0082bf;font-family:Calibri"><u>greg.j.kazz@jpl.nasa.gov</u></span></a><span
style=" font-size:11pt;font-family:Calibri">> <b><br>
Sent:</b> Tuesday, September 14, 2021 11:41 AM<b><br>
To:</b> Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND
APPLICATIONS INC] <</span><a
href="mailto:victor.j.sank@nasa.gov" moz-do-not-send="true"><span
style=" font-size:11pt;color:#0082bf;font-family:Calibri"><u>victor.j.sank@nasa.gov</u></span></a><span
style=" font-size:11pt;font-family:Calibri">><b><br>
Subject:</b> Re: [EXTERNAL] Re: Minor wording in CCSDS 732
section 4.1.2.6 Header Error Control</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri">Victor,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri">At least at JPL, no
mission uses the AOS transfer frame header error control. It
would be worthwhile if you ask Andrea that each C&S WG
member poll their respective agency to see if at the next
meeting we could see if it could be eliminated from the 732.0
blue book. </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri">Greg</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style="
font-size:11pt;font-family:Calibri"> </span></p>
<br>
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