$)C<span style=" font-size:10pt;font-family:sans-serif">Hi,</span>
<br>
<br><span style=" font-size:10pt;font-family:sans-serif">yes, I also assume
that for typical space links they would be quite similar in terms of efficiency.
I think the question is also about implementation complexity: is it 'easier'
to implement NAK-based re-transmission at high-data rates in hardware with
maybe limited resources?</span>
<br>
<br><span style=" font-size:10pt;font-family:sans-serif">Regards,<br>
Felix</span>
<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"><Tomaso.deCola@dlr.de></span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">To:
</span><span style=" font-size:9pt;font-family:sans-serif"><Jeremy.Mayer@dlr.de>,
<Felix.Flentge@esa.int>, <chkoo@kari.re.kr></span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Cc:
</span><span style=" font-size:9pt;font-family:sans-serif"><sis-dtn@mailman.ccsds.org></span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Date:
</span><span style=" font-size:9pt;font-family:sans-serif">04/04/2022
12:35</span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Subject:
</span><span style=" font-size:9pt;font-family:sans-serif">RE:
[Sis-dtn] Positive reception claim vs. Negative reception claim in LTP
Report Segment preparation and processing</span>
<br>
<hr noshade>
<br>
<br>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:11pt;font-family:Calibri">Hi
All,</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">I
tend to agree with Jeremy, from a pure ARQ effectiveness view point, using
ACK or NACK for signalling (or detecting) losses pretty much depends on
the channel model you are assuming underneath. I!/m quite sure in the
scientific literature you can find many papers about using either approach.
For typical space links, probably using ACK or NAK does not bring significant
differences from a performance standpoint. As to the optical and Ka-band
communication links, again, I!/d say it depends on the channel model and
more concretely on how packet losses are distributed after channel coding
and CRC control at frame level. In particular, it may depend on the specific
reliability measures implemented at the physical layer (e.g., long interleavers,
long codewords, etc!&), hence possibly resulting in an almost error-free
channel (with some sporadic erasures) or in a more correlated loss pattern.
At the end, I don!/t think we can come up with an ideal ARQ solution that
works at best for all possible channels!&</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">My
0.02 cents,</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">Tomaso</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"> </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:12pt;font-family:sans-serif"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:11pt;font-family:Calibri"><b>From:</b>
SIS-DTN <sis-dtn-bounces@mailman.ccsds.org> <b>On Behalf Of </b>Jeremy
Pierce-Mayer via SIS-DTN<b><br>
Sent:</b> Montag, 4. April 2022 12:09<b><br>
To:</b> Felix.Flentge@esa.int; chkoo@kari.re.kr<b><br>
Cc:</b> sis-dtn@mailman.ccsds.org<b><br>
Subject:</b> Re: [Sis-dtn] Positive reception claim vs. Negative reception
claim in LTP Report Segment preparation and processing</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:sans-serif"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri">Hi
Cheol, Felix,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri">The
efficiency of positive vs. negative claims is <b>highly</b> dependent upon
the behaviour of the underlying link. If a link has long periods of successful
communication punctuated by brief (complete) fading events, then NACK may
be better. If a link is more erratic, then the calculations become a bit
harder and are highly dependent on the ratio and duration of successful
vs lost packets/frames. </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri">In
most !0reliable!1 space links, fading is pretty intermittent (until your
elevation reduces), so ACK/NACK should be pretty similar. I think Ka/optical
might upset this balance though!& We!/ll see.</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri">Thanks,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Calibri">Jeremy</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"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:11pt;font-family:Calibri"><b>From:</b>
SIS-DTN <</span><a href="mailto:sis-dtn-bounces@mailman.ccsds.org"><span style=" font-size:11pt;color:blue;font-family:Calibri"><u>sis-dtn-bounces@mailman.ccsds.org</u></span></a><span style=" font-size:11pt;font-family:Calibri">>
<b>On Behalf Of </b>Felix Flentge via SIS-DTN<b><br>
Sent:</b> Monday, April 4, 2022 12:08 PM<b><br>
To:</b> </span><span style=" font-size:11pt;font-family:sans-serif">18C6H8</span><span style=" font-size:11pt;font-family:Calibri">
<</span><a href=mailto:chkoo@kari.re.kr><span style=" font-size:11pt;color:blue;font-family:Calibri"><u>chkoo@kari.re.kr</u></span></a><span style=" font-size:11pt;font-family:Calibri">><b><br>
Cc:</b> </span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:11pt;color:blue;font-family:Calibri"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:11pt;font-family:Calibri"><b><br>
Subject:</b> Re: [Sis-dtn] Positive reception claim vs. Negative reception
claim in LTP Report Segment preparation and processing</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:sans-serif"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial">Ah,
yes, of course you are right.</span><span style=" font-size:12pt;font-family:sans-serif">
<br>
</span><span style=" font-size:10pt;font-family:Arial"><br>
We will look into the negative ACK as part of our LTPv2 prototyping activity.</span><span style=" font-size:12pt;font-family:sans-serif">
<br>
</span><span style=" font-size:10pt;font-family:Arial"><br>
Regards,</span><span style=" font-size:12pt;font-family:sans-serif"> </span><span style=" font-size:10pt;font-family:Arial"><br>
Felix</span><span style=" font-size:12pt;font-family:sans-serif"> <br>
<br>
<br>
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
From: </span><span style=" font-size:9pt;font-family:Arial">"</span><span style=" font-size:9pt;font-family:sans-serif">18C6H8</span><span style=" font-size:9pt;font-family:Arial">"
<</span><a href=mailto:chkoo@kari.re.kr><span style=" font-size:9pt;color:blue;font-family:Arial"><u>chkoo@kari.re.kr</u></span></a><span style=" font-size:9pt;font-family:Arial">></span><span style=" font-size:12pt;font-family:sans-serif">
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
To: </span><span style=" font-size:9pt;font-family:Arial"><</span><a href=mailto:Felix.Flentge@esa.int><span style=" font-size:9pt;color:blue;font-family:Arial"><u>Felix.Flentge@esa.int</u></span></a><span style=" font-size:9pt;font-family:Arial">></span><span style=" font-size:12pt;font-family:sans-serif">
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Cc: </span><span style=" font-size:9pt;font-family:Arial">"</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">"
<</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">></span><span style=" font-size:12pt;font-family:sans-serif">
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Date: </span><span style=" font-size:9pt;font-family:Arial">04/04/2022
11:58</span><span style=" font-size:12pt;font-family:sans-serif"> </span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Subject: </span><span style=" font-size:9pt;font-family:Arial">RE:
Re: [Sis-dtn] Positive reception claim vs. Negative reception claim in
LTP Report Segment preparation and processing</span><span style=" font-size:12pt;font-family:sans-serif">
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Sent by: </span><a href=mailto:chkoo@kari.re.kr><span style=" font-size:9pt;color:blue;font-family:Arial"><u>chkoo@kari.re.kr</u></span></a><span style=" font-size:12pt;font-family:sans-serif">
</span></p>
<div align=center>
<hr noshade></div>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:sans-serif"><br>
<br>
<br>
Hi Felix, <br>
<br>
I think current LTP spec quite works well with negative claim also. Consider
below reception claim according to the LTP spec but negative claim. <br>
<br>
lower bound = 0 <br>
upper bound = 7000 <br>
negative reception claim count = 1 <br>
offset = 1000 <br>
length = 2000 <br>
<br>
it means a receiver is requesting block of segements which starts at 1000
and length is 2000, i.e., 1000 ~ 2999, for retransmission. <br>
A sender can safely remove 2 blocks, i.e., 0 - 999 and 3000 - 7000. I think
it is simpler, lower overhead and *importantly* easier to calculate (acutally
no painful for localizing the target segment position). <br>
<br>
Cheol </span></p>
<p style="margin-top:450pt;?(*
(OO
e., 0 - 999 and 3000 - 7000. I think
it is simpler, lower overhead and *importantly* easier to calculate (acutally
no painful for localizing the target segment po</span>"><span style=" font-size:9pt;color:#0062e1;font-family:Arial"><b>---------
</b></span><span style=" font-size:9pt;color:#0062e1;font-family:sans-serif"><b>?x:;</b></span><span style=" font-size:9pt;color:#0062e1;font-family:Arial"><b>
</b></span><span style=" font-size:9pt;color:#0062e1;font-family:sans-serif"><b>8^@O</b></span><span style=" font-size:9pt;color:#0062e1;font-family:Arial"><b>
---------</b></span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:9pt;font-family:sans-serif"><b><br>
:83=;g6w</b></span><span style=" font-size:9pt;font-family:Arial">
: <</span><a href=mailto:Felix.Flentge@esa.int><span style=" font-size:9pt;color:blue;font-family:Arial"><u>Felix.Flentge@esa.int</u></span></a><span style=" font-size:9pt;font-family:Arial">></span><span style=" font-size:9pt;font-family:sans-serif"><b><br>
9^4B;g6w</b></span><span style=" font-size:9pt;font-family:Arial">
: "</span><span style=" font-size:9pt;font-family:sans-serif">18C6H8</span><span style=" font-size:9pt;font-family:Arial">"
<</span><a href=mailto:chkoo@kari.re.kr><span style=" font-size:9pt;color:blue;font-family:Arial"><u>chkoo@kari.re.kr</u></span></a><span style=" font-size:9pt;font-family:Arial">></span><span style=" font-size:9pt;font-family:sans-serif"><b><br>
B|A6</b></span><span style=" font-size:9pt;font-family:Arial"> : "</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">"
<</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">></span><span style=" font-size:9pt;font-family:sans-serif"><b><br>
9^@:3/B%</b></span><span style=" font-size:9pt;font-family:Arial">
: 2022-04-04 (</span><span style=" font-size:9pt;font-family:sans-serif">?y</span><span style=" font-size:9pt;font-family:Arial">)
17:40:24</span><span style=" font-size:9pt;font-family:sans-serif"><b><br>
A&8q</b></span><span style=" font-size:9pt;font-family:Arial"> : Re:
[Sis-dtn] Positive reception claim vs. Negative reception claim in LTP
Report Segment preparation and processing</span><span style=" font-size:12pt;font-family:sans-serif">
</span><span style=" font-size:10pt;font-family:Arial"><br>
Hi Cheol,</span><span style=" font-size:9pt;font-family:Arial"> </span><span style=" font-size:10pt;font-family:Arial"><br>
<br>
interesting question. One thing I can think of is that the positive claims
would allow you to free memory earlier while for negative claims you need
to wait until the end of a session.</span><span style=" font-size:9pt;font-family:Arial">
</span><span style=" font-size:10pt;font-family:Arial"><br>
<br>
Regards,</span><span style=" font-size:9pt;font-family:Arial"> </span><span style=" font-size:10pt;font-family:Arial"><br>
Felix</span><span style=" font-size:9pt;font-family:Arial"> <br>
<br>
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
<br>
From: </span><span style=" font-size:9pt;font-family:Arial">"</span><span style=" font-size:9pt;font-family:sans-serif">18C6H8</span><span style=" font-size:9pt;font-family:Arial">
via SIS-DTN" <</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">>
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
To: </span><span style=" font-size:9pt;font-family:Arial">"</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">"
<</span><a href="mailto:sis-dtn@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">>
</span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Date: </span><span style=" font-size:9pt;font-family:Arial">04/04/2022
10:15 </span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Subject: </span><span style=" font-size:9pt;font-family:Arial">[Sis-dtn]
Positive reception claim vs. Negative reception claim in LTP Report Segment
preparation and processing </span><span style=" font-size:9pt;color:#5f5f5f;font-family:Arial"><br>
Sent by: </span><span style=" font-size:9pt;font-family:Arial">"SIS-DTN"
<</span><a href="mailto:sis-dtn-bounces@mailman.ccsds.org"><span style=" font-size:9pt;color:blue;font-family:Arial"><u>sis-dtn-bounces@mailman.ccsds.org</u></span></a><span style=" font-size:9pt;font-family:Arial">>
</span></p>
<div align=center>
<hr noshade></div>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:sans-serif"><br>
</span><span style=" font-size:10pt;font-family:Arial"><br>
Greetings,</span><span style=" font-size:9pt;font-family:Arial"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial">This
is Cheol. I am developing an LTP reference implementation. During reading
the LTP specification (RFC-5326), the preparation of reception claim in
Report Segment makes me confusing about why it is positive claim not negative
claim for segments that were not received successfully (i.e., NAK).</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial">For
reference, CFDP!/s NAK PDU has the negative claim structure when it is
requested to report missing PDUs. Does anyone know about the background
of choosing the positive claim for NAK operation in LTP?</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial">I
think negative claim is simpler and more efficient in terms of overhead
for sender and receiver both.</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial">I
like to listen experts!/ opinion on LTP operation and honestly hope it
to be changed in newly coming LTP spec.</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:10pt;font-family:Arial">Cheol</span></p>
<p style="margin-top:0px;margin-Bottom:240px"><span style=" font-size:10pt;font-family:Arial"><br>
<br>
_______________________________________________<br>
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</u></span><a href="https://protect2.fireeye.com/v1/url?k=933edf14-cca5b51c-933bae9a-ac1f6bdccbcc-93bc8ad36316533d&q=1&e=24a03daf-8e73-4317-a689-3216c529ea83&u=https%3A%2F%2Fmailman.ccsds.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fsis-dtn"><span style=" font-size:10pt;color:blue;font-family:Arial"><u>https://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-dtn</u></span></a><span style=" font-size:9pt;font-family:Arial"><br>
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<br>
</span></p>
<p style="margin-top:0px;margin-Bottom:240px"></p>
<p style="margin-top:0px;margin-Bottom:240px"></p>