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<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'>I'm in the middle of a NASA research project and lab
assessment of IPSec for use in space to ground communication. I could use a
little advise from the experts.<o:p></o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'>A (perhaps) unique aspect of our space - ground communication
path is that there are predictable periods of 1-way comm where only the forward
link or return link is available. During these periods we must continue to
communicate over whichever direction is available. One example would be to
continue the return link flow of health and status data to the ground when the
forward link is unavailable.<o:p></o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'>During an earlier phase of this study we
demonstrated that manual keying provides one approach for dealing with periods
of 1-way comm. Existing manual keyed SAs continue to flow and new ones can
initiate provided they match a defined transform set. These SAs never expire.
But there are well known limitations to manual keying that we hope to avoid.<o:p></o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'>IKE-based keying is a goal of the study and there is
an aspect where your expertise and advise would be appreciated. We think we
know that existing IKE-based SAs will continue to allow data to flow over 1-way
links until the associated SA expires. Our current goal is to develop a command
that will allow all SAs to reset their expiration timers before the start of a
1-way comm period. We've been looking over the Openswan source considering
various ways this could be done and have not identified a good approach. I
would appreciate any suggestions you may have before I charge off on
non-productive paths. <o:p></o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Thank
you in advance for any assistance you are able to provide.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Phillip
</span><o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
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