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<p class="MsoNormal">Regarding BSSP and the MIWG RTP proposal:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">These are neither the same, nor are they functionally or operationally equivalent.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><u>We (the DTN and DSN community at JPL) are asking for a formal CCSDS specification for BSSP.</u> It is already in use in KPLO (and the “non-standard” issue Marc mentioned is that they have such a constrained uplink that they do not use
the reliable ARQ part of BSSP), but without a specification, neither the DSN nor any programs may use the BSSP service in the DSN in any sort of formal manner (i.e. with service agreements), nor can it be specified in any contractual documents.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Besides KPLO, we already have two other commercial interests that seem to be planning on using BSSP.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It is not a question choosing between BSSP or RTP/Bundles – BSSP functions as both a real-time streaming service (modulo OWLT), as well as a
<i>reliable </i>streaming service using both reliable and unreliable channels. This capability is not part of the RTP redbook. I haven’t had time to study the RTP proposal – none of us in SIS-DTN even knew about it until last week’s F2F meeting – but at first
glance, the two protocols don’t seem to be competing or overlapping except in the highest level of sending some sort of real-time unreliable video over DTN.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Which reminds me: I believe the RTP/Bundles calls for DTN Multicast. That is also a key protocol for DTKA as well. So getting a multicast spec in place is important. We’ll probably have a need for both BSSP and multicast long before we
try to put LTP2 into use anywhere.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal">Leigh<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">SIS-DTN <sis-dtn-bounces@mailman.ccsds.org> on behalf of "Sanchez Net, Marc (US 332H) via SIS-DTN" <sis-dtn@mailman.ccsds.org><br>
<b>Reply-To: </b>"Sanchez Net, Marc (US 332H)" <marc.sanchez.net@jpl.nasa.gov><br>
<b>Date: </b>Monday, February 13, 2023 at 9:10 AM<br>
<b>To: </b>"sis-dtn@mailman.ccsds.org" <sis-dtn@mailman.ccsds.org><br>
<b>Subject: </b>[EXTERNAL] [Sis-dtn] Notes from the NASA DTN F2F Meeting<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
</div>
<p class="MsoNormal">Hi All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Here are the notes/questions for the SIS-DTN WG that I recorded at the NASA DTN face-to-face meeting.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo3">BPv7<o:p></o:p></li><ul style="margin-top:0in" type="circle">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Leigh Torgerson pointed out that in the assumptions of the proposed RTP book there is the following statement: “<i>arbitrary bundle sizes—the multicast mechanism must not impose arbitrary
limits that are less than the maximum bundle size on the size of bundles.”</i>. The question then becomes whether having a bundle size (10 MB) in the spec restricts other specifications in any way.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Should we add a requirement (maybe a “should” rather than a “shall”) for CLAs to notify BP when transmission with that CLA is possible? This would provide minimal indication of whether
transmission via a CLA is possible.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Compressed Bundle Reporting:<o:p></o:p></li><ul style="margin-top:0in" type="square">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">How that CBR handle bundle fragmentation?<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">Why do we need CBR to define a new extension block with the FSN and flow sequence? PACE is using the service numbers in the transmit EID as the FSN, so they are able to uniquely identify
flows and bundles within the flow without having an extension block.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">Should we have a dedicated reporting mechanism for bundle expiration?<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">Can we make bundle reporting extensible so that missions have the ability to have their reporting reasons?<o:p></o:p></li></ul>
</ul>
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo3">LTPv2<o:p></o:p></li><ul style="margin-top:0in" type="circle">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Will LTPv2 have a way to signal to the receiver the size of the LTP block? This would facilitate memory allocation at the receiver.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Will LTPv2 have a “hook” to get notified when the underlying link is down. This can be used to pause timers, etc.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Will LTPv2 have a way to aggregate report segments and report segment acknowledgements to reduce overhead?<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Will LTPv2 have a ping mechanism for the tx/rx engines to assess whether the link is running?<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Will LTPv2 have a concept of transmission deadline, which causes the tx to stop sending a block if it is not available at the destination by a certain moment? This could be used in
conjunction with the bundle lifetime to cancel LTPv2 sessions proactively.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">APL has reported the following issues related to LTP that we way want to consider in LTPv2<o:p></o:p></li><ul style="margin-top:0in" type="square">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">Unspecified behavior that allows a memory leak and provide a method of denial-of-service attack. See
<a href="https://urldefense.us/v3/__https:/github.com/nasa/HDTN/issues/19__;!!PvBDto6Hs4WbVuu7!f6FjzDT7XX23E-j9wYbs8iSbSA02D4LRrMaXGhkPFZSRLnwv1xxqTyZRV8XQb0cuC9EtYg$">
https://github.com/nasa/HDTN/issues/19</a><o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">LTP should guarantee that a reception report is sent when all data is received, not necessarily in response to a checkpoint. See
<a href="https://urldefense.us/v3/__https:/github.com/nasa/HDTN/issues/23__;!!PvBDto6Hs4WbVuu7!f6FjzDT7XX23E-j9wYbs8iSbSA02D4LRrMaXGhkPFZSRLnwv1xxqTyZRV8XQb0dI3RG5MA$">
https://github.com/nasa/HDTN/issues/23</a> <o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level3 lfo3">LTP should allow the transmit engine to delay sending data segments or reports long enough to receive out-of-order segments that would affect the retransmission behavior. See
<a href="https://urldefense.us/v3/__https:/github.com/nasa/HDTN/issues/22__;!!PvBDto6Hs4WbVuu7!f6FjzDT7XX23E-j9wYbs8iSbSA02D4LRrMaXGhkPFZSRLnwv1xxqTyZRV8XQb0fue9px_w$">
https://github.com/nasa/HDTN/issues/22</a> and <a href="https://urldefense.us/v3/__https:/github.com/nasa/HDTN/issues/24__;!!PvBDto6Hs4WbVuu7!f6FjzDT7XX23E-j9wYbs8iSbSA02D4LRrMaXGhkPFZSRLnwv1xxqTyZRV8XQb0cjiGWWdg$">
https://github.com/nasa/HDTN/issues/24</a>. <o:p></o:p></li></ul>
</ul>
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo3">Others wishes from the community<o:p></o:p></li><ul style="margin-top:0in" type="circle">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">DTN multicast<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Provide mechanisms for in-order delivery, lack of gaps, and lack of duplicates (similar to DTPC, but more modular, any possibly not end-to-end)<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Standard CCSDS format for contact plans<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">DNS-like service to avoid having to manually rely on IANA/SANA registries.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level2 lfo3">Stream of video/voice via DTN. KPLO used a non-standard version of BSSP and yet SIS-MIA might be working on RTP over DTN.<o:p></o:p></li></ul>
</ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">-----------------------------------------------------------------------------------------------------------------------<o:p></o:p></p>
<p class="MsoNormal">Marc Sanchez Net (332H)<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:gray">Telecommunications Engineer</span><o:p></o:p></p>
<p class="MsoNormal" style="background:white"><span style="font-size:10.0pt;color:gray">Jet Propulsion Laboratory<o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:10.0pt;color:gray">Cell:</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222"> </span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"><a href="mailto:(617)%20953-7977">(617)
953-7977</a></span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#0070C0">
</span><span style="font-size:10.0pt;color:gray">|</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#0070C0">
</span><span style="font-size:10.0pt;color:gray">Email:</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#222222"> </span><span style="color:black"><a href="mailto:marc.sanchez.net@jpl.nasa.gov"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:blue">marc.sanchez.net@jpl.nasa.gov</span></a></span><span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:#222222"><o:p></o:p></span></p>
<p class="MsoNormal">-----------------------------------------------------------------------------------------------------------------------<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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