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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Marc, thanks for sending this on. A couple of thoughts in-line below.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Scott<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b>From:</b> SIS-DTN <sis-dtn-bounces@mailman.ccsds.org> <b>On Behalf Of </b>Sanchez Net, Marc (US 332H) via SIS-DTN<br><b>Sent:</b> Monday, February 13, 2023 9:10 AM<br><b>To:</b> sis-dtn@mailman.ccsds.org<br><b>Subject:</b> [Sis-dtn] Notes from the NASA DTN F2F Meeting<o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><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:l2 level1 lfo3'>BPv7<o:p></o:p></li><ul style='margin-top:0in' type=circle><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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:l2 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></ul></ul><ul style='margin-top:0in' type=disc><li class=MsoListParagraph style='margin-left:0in;mso-list:l1 level1 lfo4'>Would this be a requirement that implementations would have to satisfy in order to be considered BPv7 compliant? Isn’t it strictly an implementation consideration? How would it contribute to interoperability?<o:p></o:p></li></ul><ul style='margin-top:0in' type=disc><ul style='margin-top:0in' type=circle><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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:l2 level3 lfo3'>How that CBR handle bundle fragmentation?<o:p></o:p></li></ul></ul></ul><ul style='margin-top:0in' type=disc><li class=MsoListParagraph style='margin-left:0in;mso-list:l1 level1 lfo4'>I would think that fragmentary bundles are simply bundles; they should be reported to the nodes that created them, that is, the nodes that generated the fragments.<o:p></o:p></li></ul><ul style='margin-top:0in' type=disc><ul style='margin-top:0in' type=circle><ul style='margin-top:0in' type=square><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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:l2 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:l2 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:l2 level1 lfo3'>LTPv2<o:p></o:p></li><ul style='margin-top:0in' type=circle><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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:l2 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:l2 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:l2 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:l2 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:l2 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:l2 level3 lfo3'>Unspecified behavior that allows a memory leak and provide a method of denial-of-service attack. See <a href="https://github.com/nasa/HDTN/issues/19">https://github.com/nasa/HDTN/issues/19</a><o:p></o:p></li><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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://github.com/nasa/HDTN/issues/23">https://github.com/nasa/HDTN/issues/23</a> <o:p></o:p></li><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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://github.com/nasa/HDTN/issues/22">https://github.com/nasa/HDTN/issues/22</a> and <a href="https://github.com/nasa/HDTN/issues/24">https://github.com/nasa/HDTN/issues/24</a>. <o:p></o:p></li></ul></ul><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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:l2 level2 lfo3'>DTN multicast<o:p></o:p></li><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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></ul></ul><ul style='margin-top:0in' type=disc><li class=MsoListParagraph style='margin-left:0in;mso-list:l1 level1 lfo4'>Having more options on the DTPC feature menu has been an open item for many years. DTPC is just a prototocol that ought to be stackable like any other protocol. If the DTPC spec says that the layer above it can only be the end-to-end user application, then the spec should be revised.<o:p></o:p></li></ul><ul style='margin-top:0in' type=disc><ul style='margin-top:0in' type=circle><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 level2 lfo3'>Standard CCSDS format for contact plans<o:p></o:p></li><li class=MsoListParagraph style='margin-left:0in;mso-list:l2 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:l2 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></div></body></html>