<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Good hint, John. <div>It looks as we shall carry out a good comparison of the the homonymous services and determine the real deltas. It may be that in SPP only a Space Packet Multiplexing is required. </div><div>Regards</div><div>Gian Paolo<br><br><div id="AppleMailSignature">Sent from my iPhone</div><div><br>On 27. Jan 2018, at 16:21, John Pietras <<a href="mailto:john.pietras@gst.com">john.pietras@gst.com</a>> wrote:<br><br></div><blockquote type="cite"><div>
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<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Members of the SLPWG,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">I have read through Greg’s summary of his conversation with Takahiro regarding suggested simplifications of the SPP book. One of those suggested changes is the removal of the Packet Service,
which the memo implied was redundant with this Packet Service provided by the Space Data Link Protocols. This is not quite true – the Packet Service that is provided by the SPP provides the additional functionality of muxing/demuxing Packets with different
APIDs into/out of a single VC. <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">Admittedly, I have been away from the day-to-day considerations of space link protocols for many years, but having been a member of the Panel 1 F/G team that wrote the original AOS Blue Book
I can attest to the fact that the ability to flow multiple “packet channels” through a single VC was an important aspect of the protocol stack, at least at the time (late 80s). Unless there is no longer a perceived need to do such packet channel muxing/demuxing,
such a capability would have to be retained in the SPP book or re-integrated into the various SDLP books as appropriate.
<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 will agree that calling both the SPP “Packet Services” and the SLDP “Packet Services” by the same name is confusing and can lead to overlooking this additional functionality of the SPP flavor
of the service. Perhaps a different name to distinguish them would be useful.<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">John Pietras<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:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> SLS-SLP [<a href="mailto:sls-slp-bounces@mailman.ccsds.org">mailto:sls-slp-bounces@mailman.ccsds.org</a>]
<b>On Behalf Of </b>Kazz, Greg J (312B)<br>
<b>Sent:</b> Thursday, January 25, 2018 5:41 PM<br>
<b>To:</b> <a href="mailto:sls-slp@mailman.ccsds.org">sls-slp@mailman.ccsds.org</a><br>
<b>Subject:</b> [Sls-slp] Results of Discussion with Takahiro Yamada on Revising SPP Blue Book<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Dear SLP WG,<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">Happy New Year 2018 !<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">This topic concerns the new project recently approved for revising the Space Packet Protocol (SPP) Blue book.<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">Please read the attached Word file that contains a discussion I had with Takahiro Yamada, the driving force in the CCSDS restructuring of the Packet Telemetry Blue Book. Parts of that book under Takahiro’s
guidance became the Space Packet Protocol, SPP, which we are now tasked to revise and update.<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">I have made several suggestions about removing sections of the existing SPP document and I have asked Takahiro to give us his opinion about it.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I would like to hold a 1 hour telecon on this subject in the very near future. I will set up a doodle poll to determine when the best time will be to discuss this topic. Please look forward to the invitation.
If you don’t see one, please let me know so that I can add you to the list, if I missed you.<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">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Greg<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">CCSDS SLP WG Chairman<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">Greg Kazz<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Principal Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Technical Group Supervisor,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Project Software and End-to-End Information Systems Engineering (312B)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Jet Propulsion Laboratory<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">4800 Oak Grove Dr., M/S 301-490<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">Pasadena, CA 91109</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">1+(818)393 6529(voice)</span><span style="font-size:11.0pt"><o:p></o:p></span></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><span style="font-size:11.0pt"><o:p></o:p></span></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><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Times New Roman","serif""><o:p> </o:p></span></p>
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