<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">In the FWIW category, I remember that network partitions (between the East and West Coasts) occurred, not often but often enough to be noticeable, until the 3rd cross-country line went in. Then they were pretty much a rarity, if they occurred at all. Illinois was one of the jumping off points between East and West, so perhaps we just noticed them more.<div class=""><br class=""></div><div class="">John<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Feb 16, 2019, at 11:25, Steve Crocker <<a href="mailto:steve@shinkuro.com" class="">steve@shinkuro.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_quote"><div class="gmail_attr">My brother forwarded the appended thread. It reminded me that I had previously been unsuccessful at joining this list, but I am now on the list.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">Over the years I have heard many times from many different people and also seen in print the idea that the Arpanet was motivated and built for nuclear survivability. Moreover, Steve Lukasik, the director of (D)ARPA for several of the critical years, included this as one of his reasons for signing the checks for the Arpanet.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">I think it will be helpful to make a couple of distinctions regarding network survivability. Let me offer two dimensions and at least two levels of disruption for each.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr"><b class="">Equipment outage</b>: When a link or a router becomes unusable, it's necessary to route around the loss. It makes a big difference if only a few links or routers are down versus a significant fraction are down. In normal circumstances, it is expected some lines and some routers will be out of service from time to time. In contrast, if there is an attack, the outages might be substantial and perhaps purposefully coordinated.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr"><b class="">Traffic level</b>: In normal operation, the total traffic is within the capacity of the network. In extraordinary times, the traffic level surges beyond the capacity of the system. Surges happen for various reasons. There might be a very popular web site, e.g. the Victoria Secrets incident, or a DDoS attack.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">Arguably the Arpanet design addressed survivability for the case when a small number of links or routers were out and traffic levels were normal. Alex colorfully describes Frank Heart's concerns for the risks to individual IMPs placed in the very risky environments of universities.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">The Arpanet design did not address the issue of large scale outages nor did it include strategies for dealing with overload. In contrast, a serious design to address post-nuclear operation would have had to address the combination of substantial loss of equipment and a huge spike in urgent traffic.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">In the conversations I've had with Lukasik on this matter, he says he had in mind the technology could lead to designs that would have that level of survivability, and that it was helpful to include this in defending the funding for the network. And, as Vint says, subsequent projects explored reconstitution in the event of certain kinds of disconnections. However, I believe the level of outages explored in those projects were well below the levels that would have occurred in a large scale nuclear confrontation.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">In 2017, I ran this question past Larry Roberts. His short reply was he would have had to connect each IMP to four others instead of only two or three others.</div><div class="gmail_attr"><br class=""></div><div class="gmail_attr">Steve</div><div class="gmail_attr"><br class=""></div>
<br class="">
-------- Forwarded Message --------<br class="">
Subject: Re: [ih] When the words Internet was design to survive a <br class="">
nuclear war appeared for the first time?<br class="">
Date: Thu, 14 Feb 2019 12:30:36 -0500<br class="">
From: Vint Cerf <<a href="mailto:vint@google.com" target="_blank" class="">vint@google.com</a>><br class="">
To: Alex McKenzie <<a href="mailto:aamsendonly396@gmail.com" target="_blank" class="">aamsendonly396@gmail.com</a>><br class="">
CC: internet history <<a href="mailto:internet-history@postel.org" target="_blank" class="">internet-history@postel.org</a>><br class="">
<br class="">
<br class="">
<br class="">
Alex is essentially correct. Paul Baran's work WAS aimed at post-nuclear <br class="">
survival but he never got to try his ideas out as they<br class="">
were rejected as unimplementable or uninteresting by a circuit-switching <br class="">
oriented Defense Communications Agency.<br class="">
<br class="">
Larry Roberts was clear that the ARPANET was intended to support <br class="">
resource sharing.<br class="">
<br class="">
By the time Bob Kahn and I started working on Internet with its focus on <br class="">
command/control, the issue of survivability<br class="">
was back on the table. The multi-network design contemplated multiple <br class="">
networks operated by distinct entities<br class="">
(in the DoD perspective it was multiple countries or aggregates like <br class="">
NATO) and resilience was important. I went<br class="">
so far as to commission a test in which we flew packet radios in <br class="">
Strategic Air Command aircraft, artificially "broke"<br class="">
the ARPANET up into fragments and re-integrated them through ground to <br class="">
air packet radio connectivity. I was<br class="">
particularly worried about the partitioning of a constituent network <br class="">
which would cause great confusion for the<br class="">
routing algorithm (a source gateway might know know to which "half" of <br class="">
the fragmented network a packet should<br class="">
be sent. My hazy recollection is that Radia Perlman came up with a way <br class="">
to solve that problem that involved<br class="">
creating new autonomous systems out of each "piece" and re-enabling <br class="">
routing algorithms.<br class="">
<br class="">
vint<br class="">
<br class="">
<br class="">
On Thu, Feb 14, 2019 at 12:18 PM Alex McKenzie <<a href="mailto:aamsendonly396@gmail.com" target="_blank" class="">aamsendonly396@gmail.com</a> <br class="">
<mailto:<a href="mailto:aamsendonly396@gmail.com" target="_blank" class="">aamsendonly396@gmail.com</a>>> wrote:<br class="">
<br class="">
Miles,<br class="">
<br class="">
I believe the emphasis on survivability came from Frank Heart.<br class="">
Building the early ARPAnet was a very risky project, in the sense<br class="">
that there was a tight deadline, it would be easy to see if it<br class="">
worked or not, and most people didn't believe it would work.<br class="">
Frank's reputation was very much on the line. The ruggedized IMP<br class="">
cabinet was part of his emphasis on controlling everything the team<br class="">
could control, to minimize risk. But the particular risks the<br class="">
ruggedized cabinet was intended to protect against were:<br class="">
- careless site personnel, who cared about their own computers but<br class="">
might be expected to stick the IMP in a storage closet where<br class="">
maintenance workers would bump it, and<br class="">
- graduate students who might be inclined to study it, perhaps with<br class="">
destructive results. (Lest this seem outlandish, the TIP in Hawaii<br class="">
was a sore spot of unreliability when I was running the NCC -<br class="">
turned out a graduate student was crashing it every day by taping<br class="">
into its power supply which was just right for his project. The TIP<br class="">
was NOT in a ruggedized box.)<br class="">
The group was not trying to protect against EMP.<br class="">
<br class="">
More generally, if the ARPAnet had been designed to survive a<br class="">
nuclear attack it would have been necessary to insure that the<br class="">
IMP-to_IMP circuits did not go through the small number of Telco<br class="">
offices which made up the Telco backbone. No effort was made to<br class="">
influence the provisioning of these circuits, and it can be presumed<br class="">
that loss of only a few major cities would have resulted in most of<br class="">
the leased lines disappearing.<br class="">
<br class="">
Cheers,<br class="">
Alex<br class="">
<br class="">
On Thu, Feb 14, 2019 at 10:48 AM Miles Fidelman<br class="">
<<a href="mailto:mfidelman@meetinghouse.net" target="_blank" class="">mfidelman@meetinghouse.net</a> <mailto:<a href="mailto:mfidelman@meetinghouse.net" target="_blank" class="">mfidelman@meetinghouse.net</a>>> wrote:<br class="">
<br class="">
Bernie,<br class="">
<br class="">
On 2/14/19 9:28 AM, Bernie Cosell wrote:<br class="">
<br class="">
> On February 14, 2019 09:13:42 Alejandro Acosta<br class="">
> <<a href="mailto:alejandroacostaalamo@gmail.com" target="_blank" class="">alejandroacostaalamo@gmail.com</a>><br class="">
> <mailto:<a href="mailto:alejandroacostaalamo@gmail.com" target="_blank" class="">alejandroacostaalamo@gmail.com</a>> wrote:<br class="">
><br class="">
>><br class="">
>> Today I was reading some news about Internet and in one of<br class="">
>> them I<br class="">
>> found the phrase (that all of you have listened before): <br class="">
>> "Internet<br class="">
>> (ARPANET) was intended to survive a nuclear war", however, as<br class="">
>> far as I<br class="">
>> know, this is kind of a myth, right?, ARPANET was intended as<br class="">
>> a research<br class="">
>> network and the "war" part if very far away from the thuth.<br class="">
><br class="">
> my take on that is that there were two lines of thought<br class="">
> leading up to the<br class="">
> ARPAnet. very very roughly: one was paul baran's, who was<br class="">
> thinking<br class="">
> about how the military command and control might be able to<br class="">
> continue functioning in the event of an attack, and JCR<br class="">
> Licklider, who was thinking<br class="">
> about how wide-spread researchers could share resources, ideas<br class="">
> and results<br class="">
> to better collaborate.<br class="">
><br class="">
> when the ARPAnet got funded by the DoD, Baran's story was the<br class="">
> easier to<br class="">
> understand to the average person, raather than the more<br class="">
> diaphanous idea<br class="">
> of researcher collaboration. so Baran's take kinda caught the<br class="">
> public<br class="">
> imagination, but the reality for those of us working on it was<br class="">
> the it was<br class="">
> {somehow :o)} to be a research tool.<br class="">
><br class="">
You were involved a lot earlier than I was. Perhaps you could<br class="">
comment on how much folks thought about fault-tolerance in the<br class="">
early days. It's always struck me that things like<br class="">
continuity-of-operations, in the face of node & link outages,<br class="">
and no-single-point-of-failure, were baked in from the<br class="">
beginning. You know - all the stuff that would allow the net to<br class="">
survive everything from backhoes to natural disasters, and<br class="">
coincidentally, nuclear war.<br class="">
<br class="">
On the physical side, the early IMPs were pretty rugged boxes<br class="">
(not so much C/30s and such). Were any of the IMPs built to<br class="">
withstand EMP?<br class="">
<br class="">
Miles<br class="">
<br class="">
<br class="">
<br class="">
-- In theory, there is no difference between theory and <br class="">
practice.<br class="">
In practice, there is. .... Yogi Berra<br class="">
<br class="">
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