<div dir="ltr">Alex is essentially correct. Paul Baran's work WAS aimed at post-nuclear survival but he never got to try his ideas out as they<div>were rejected as unimplementable or uninteresting by a circuit-switching oriented Defense Communications Agency. </div><div><br></div><div>Larry Roberts was clear that the ARPANET was intended to support resource sharing. </div><div><br></div><div>By the time Bob Kahn and I started working on Internet with its focus on command/control, the issue of survivability</div><div>was back on the table. The multi-network design contemplated multiple networks operated by distinct entities</div><div>(in the DoD perspective it was multiple countries or aggregates like NATO) and resilience was important. I went</div><div>so far as to commission a test in which we flew packet radios in Strategic Air Command aircraft, artificially "broke"</div><div>the ARPANET up into fragments and re-integrated them through ground to air packet radio connectivity. I was</div><div>particularly worried about the partitioning of a constituent network which would cause great confusion for the</div><div>routing algorithm (a source gateway might know know to which "half" of the fragmented network a packet should</div><div>be sent. My hazy recollection is that Radia Perlman came up with a way to solve that problem that involved </div><div>creating new autonomous systems out of each "piece" and re-enabling routing algorithms.</div><div><br></div><div>vint</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Feb 14, 2019 at 12:18 PM Alex McKenzie <<a href="mailto:aamsendonly396@gmail.com">aamsendonly396@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">
<div>Miles,</div><div><br></div><div>I believe the emphasis on
survivability came from Frank Heart. Building the early ARPAnet was a
very risky project, in the sense that there was a tight deadline, it
would be easy to see if it worked or not, and most people didn't believe
it would work. Frank's reputation was very much on the line. The
ruggedized IMP cabinet was part of his emphasis on controlling
everything the team could control, to minimize risk. But the particular
risks the ruggedized cabinet was intended to protect against were:</div><div>-
careless site personnel, who cared about their own computers but might
be expected to stick the IMP in a storage closet where maintenance
workers would bump it, and</div><div>- graduate students who might be
inclined to study it, perhaps with destructive results. (Lest this seem
outlandish, the TIP in Hawaii was a sore spot of unreliability when I
was running the NCC - turned out a graduate student was crashing it
every day by taping into its power supply which was just right for his
project. The TIP was NOT in a ruggedized box.)</div><div>The group was not trying to protect against EMP.</div><div><br></div><div>More
generally, if the ARPAnet had been designed to survive a nuclear attack
it would have been necessary to insure that the IMP-to_IMP circuits did
not go through the small number of Telco offices which made up the
Telco backbone. No effort was made to influence the provisioning of
these circuits, and it can be presumed that loss of only a few major
cities would have resulted in most of the leased lines disappearing.</div><div><br></div><div>Cheers,</div><div>Alex</div>
</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Feb 14, 2019 at 10:48 AM Miles Fidelman <<a href="mailto:mfidelman@meetinghouse.net" target="_blank">mfidelman@meetinghouse.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<p>Bernie,<br>
</p>
<p>On 2/14/19 9:28 AM, Bernie Cosell wrote:<br>
</p>
<blockquote type="cite">
<div dir="auto">
<div id="gmail-m_-6802678864709488567gmail-m_777624654623997729aqm-original" style="color:black;font-family:sans-serif">
<div dir="auto">On February 14, 2019 09:13:42 Alejandro Acosta
<a class="gmail-m_-6802678864709488567gmail-m_777624654623997729moz-txt-link-rfc2396E" href="mailto:alejandroacostaalamo@gmail.com" target="_blank"><alejandroacostaalamo@gmail.com></a> wrote:</div>
</div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><br>
</div>
<div id="gmail-m_-6802678864709488567gmail-m_777624654623997729aqm-original" style="color:black;font-family:sans-serif" dir="auto">
<blockquote type="cite" class="gmail_quote" style="margin:0px 0px 0px 0.75ex;border-left:1px solid rgb(128,128,128);padding-left:0.75ex">
<div dir="auto"><br>
</div>
<div dir="auto"> Today I was reading some news about
Internet and in one of them I</div>
<div dir="auto">found the phrase (that all of you have
listened before): "Internet</div>
<div dir="auto">(ARPANET) was intended to survive a nuclear
war", however, as far as I</div>
<div dir="auto">know, this is kind of a myth, right?,
ARPANET was intended as a research</div>
<div dir="auto">network and the "war" part if very far away
from the thuth.</div>
</blockquote>
</div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><br>
</div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif">my take on that
is that there were two lines of thought leading up to the</div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif">ARPAnet. very
very roughly: one was paul baran's, who was thinking</div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif">about how the
military <span style="font-size:12pt">command and control
might be able to continue functioning in the event of </span><span style="font-size:12pt">an attack, and JCR Licklider, who
was thinking</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">about how wide-spread researchers
could share resources, ideas and results </span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">to better collaborate.</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt"><br>
</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">when the ARPAnet got funded by the
DoD, Baran's story was the easier to</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">understand to the average person,
raather than the more diaphanous idea</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">of researcher collaboration. so
Baran's take kinda caught the public</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">imagination, but the reality for
those of us working on it was the it was</span></div>
<div dir="auto" style="font-family:"Times New Roman",Times,"Liberation Serif",serif"><span style="font-size:12pt">{somehow :o)} to be a research
tool. </span></div>
<br>
</div>
</blockquote>
<p>You were involved a lot earlier than I was. Perhaps you could
comment on how much folks thought about fault-tolerance in the
early days. It's always struck me that things like
continuity-of-operations, in the face of node & link outages,
and no-single-point-of-failure, were baked in from the beginning.
You know - all the stuff that would allow the net to survive
everything from backhoes to natural disasters, and coincidentally,
nuclear war. <br>
</p>
<p>On the physical side, the early IMPs were pretty rugged boxes
(not so much C/30s and such). Were any of the IMPs built to
withstand EMP?</p>
<p>Miles<br>
</p>
<p><br>
</p>
<p><br>
</p>
<pre class="gmail-m_-6802678864709488567gmail-m_777624654623997729moz-signature" cols="72">--
In theory, there is no difference between theory and practice.
In practice, there is. .... Yogi Berra</pre>
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