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<p class="MsoNormal"><span style="font-size:14.0pt">Greetings,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Here’s my second question w.r.t. the JAXA RIDs. This one has to do with sequential (which I interpret to mean in-order) delivery with LTP.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">JAXA-PRA1415-09 states:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">Sequential transportation is an essential function to control devices and
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">LTP can provide sequential transportation over single hop with certain parameter of RFC5326.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">This aspect should be described in this document because it is an important potential of LTP.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Is there something about RFC5326 that I missed? The Red-part data of a block is delivered atomically (so data is in-order within the Red Part I suppose) but I don’t think LTP guarantees anything beyond that.
In particular:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:14.0pt;font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:14.0pt">The Red Part of a block might be delivered before, after, or in the middle of Green Data for that block.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:14.0pt;font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:14.0pt">The relative arrival times of Red and Green data from multiple blocks transmitted simultaneously are undefined by the spec.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">The only way I know of to ensure in-order arrival of data would be to use only red data and to wait for the report indicating complete reception of one block before completing transmission of the next (red)
block. That’s possible, but it would be an implementation decision not part of the specification.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Am I missing something here?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">JAXA-PRA1415-10 states:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">To control sequential transportation over multi-hop communication,
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">RFC and Red Book should contain the description of the interface and<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">rule as SAP of LTP like the option of Green-Data.
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">LTP can naturally support single hop sequential transportation,
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:14.0pt">but multi hop transportation needs some handling of hop-to-hop interaction.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">The Delay-Tolerant Payload Conditioning (DTPC) in the BP-for-CCSDS book provides an in-order delivery service. As with the above (09) I don’t think there’s anything in the LTP spec (RFC5326 or LTP-for-CCSDS)
that says anything about providing in-order delivery of LTP blocks (or Green-part segments).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Does anyone interpret these differently? If not then I’m going to suggest adding a NOTE specifically stating that in-order delivery is not an LTP service, but multi-hop (or single-hop, if BP is deployed on
both ends of the link) in-order delivery is achievable with BP and DTPC.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"> --keith<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
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