<font size=2 face="sans-serif">Dear CSTS WG,</font>
<br><font size=2 face="sans-serif">Please have a look at Wolfgang's email
below. Feedback is appreciated!</font>
<br>
<br><font size=2 face="sans-serif">Regards,</font>
<br><font size=2 face="sans-serif">Holger</font>
<br>
<br><font size=2 face="sans-serif">Holger Dreihahn<br>
European Spacecraft Operations Centre | European Space Agency | S-431<br>
+49 6151 90 2233 | </font><a href=http://www.esa.int/esoc><font size=2 face="sans-serif">http://www.esa.int/esoc</font></a>
<br><font size=1 color=#800080 face="sans-serif">----- Forwarded by Holger
Dreihahn/esoc/ESA on 03/07/2019 14:09 -----</font>
<br>
<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">"Wolfgang Hell"
<wo_._he@t-online.de></font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">"Holger Dreihahn"
<Holger.Dreihahn@esa.int></font>
<br><font size=1 color=#5f5f5f face="sans-serif">Cc:
</font><font size=1 face="sans-serif">"John Pietras"
<john.pietras@gst.com></font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">02/07/2019 14:49</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">Merging of FRs
dealing with variable length frames</font>
<br>
<hr noshade>
<br>
<br>
<br><font size=3>Hi Holger,</font>
<p><font size=3>can you please forward this material to the CSTS-WG? I'm
copying John directly, because I suspect that he may have some more or
less immediate comments while the other WG members presumably will need
more time to digest this input (as for John's input for the fixed length
frames). Any early feedback WG members might have will of course be helpful.</font>
<p><font size=3>My assumption is that variable length frames will be used
on the forward link only and therefore we do not need to investigate which
parameters are required for the return link.</font>
<p><font size=3>The only Sync and Coding sublayer that may be used in combination
with variable length USLP frames are CCSDS 231.0-B-3 and CCSDS 211.0-B-5,
where the latter addresses the proximity link. My understanding is that
the FR specifications deal only with the Forward Link as emitted by an
ESLT, but not with inter-spacecraft communications. Therefore only CCSDS
231.0-B-3 needs to be taken into account in the FR specification context.
That means that the Sync and Coding layer is the same for both USLP and
TC frames and no merging of separate FR types is needed in that respect.
For the sake of completeness the attached spreadsheet comparing the USLP
and TC cases presents also the managed parameters of the sync and coding
sublayer, i.e., of CCSDS 231.0-B-3.If deemed useful, I can add the VOP-1
managed parameters to the next issue of the spreadsheet. Again, these parameters
are common for variable length USLP and for TC frames.</font>
<p><font size=3>I have applied the following color coding in the spreadsheet:
Those parameters that are identical or reasonably similar so that they
can be used both to monitor and, if applicable, control USLP and TC frame
handling have a green background. Those parameters that apply only to one
frame type have a blue background. A red background indicates that I see
a problem with merging USLP and TC or where I have a problem with the specification
of the managed parameters ar generated by the space link folks.</font>
<p><font size=3>As the next steps I plan to crosscheck my findings and
suggestions against the material generated by John and to suggest an initial
mapping of the parameters to FR types. Hopefully we can reach some related
conclusions on July 9 such that we have a reasonably stable starting point
for reworking some of the FR type specifications.</font>
<p><font size=3>Best regards,</font>
<p><font size=3>Wolfgang</font>
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