[ih] nice story about dave mills and NTP

[Jorge Amodio]

Excellent story! 

Thanks for sharing Jack.

Cheers
- Jorge (mobile)


> On Oct 1, 2022, at 11:36 PM, Jack Haverty via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> On 10/1/22 16:30, vinton cerf via Internet-history wrote:
>> in the New Yorker
>> 
>> https://www.newyorker.com/tech/annals-of-technology/the-thorny-problem-of-keeping-the-internets-time
>> 
>> v
> 
> Agree, nice story.   Dave did a *lot* of good work.  Reading the article reminded me of the genesis of NTP.
> 
> IIRC....
> 
> Back in the early days circa 1980, Dave was the unabashed tinkerer, experimenter, and scientist.  Like all good scientists, he wanted to run experiments to explore what the newfangled Internet was doing and test his theories.   To do that required measurements and data.
> 
> At the time, BBN was responsible for the "core gateways" that provided most of the long-haul Internet connectivity, e.g., between US west and east coasts and Europe.  There were lots of ideas about how to do things - e.g., strategies for TCP retransmissions, techniques for maintaining dynamic tables of routing information, algorithms for dealing with limited bandwidth and memory, and other such stuff that was all intentionally very loosely defined within the protocols.   The Internet was an Experiment.
> 
> I remember talking with Dave back at the early Internet meetings, and his fervor to try things out, and his disappointment at the lack of the core gateway's ability to measure much of anything.   In particular, it was difficult to measure how long things took in the Internet, since the gateways didn't even have real-time clocks. This caused a lot of concern about protocol elements such as Time-To-Live, which were temporarily to be implemented purely as "hop counts", pending the introduction of some mechanism for measuring Time into the gateways.  (AFAIK, we're still waiting....)
> 
> Curiously, in the pre-Internet days of the ARPANET, the ARPANET IMPs did have a pretty good mechanism for measuring time, at least between pairs of IMPs at either end of a communications circuit, because such circuits ran at specific speeds.   So one IMP could tell how long it was taking to communicate with one of its neighbors, and used such data to drive the ARPANET internal routing mechanisms.
> 
> In the Internet, gateways couldn't tell how long it took to send a datagram over one of its attached networks.   The networks of the day simply didn't make such information available to its "users" (e.g., a gateway).
> 
> But experiments require data, and labs require instruments to collect that data, and Dave wanted to test out lots of ideas, and we (BBN) couldn't offer any hope of such instrumentation in the core gateways any time soon.
> 
> So Dave built it.
> 
> And that's how NTP got started.  IIRC, the rest of us were all just trying to get the Internet to work at all.   Dave was interested in understanding how and why it worked.  So while he built NTP, that didn't really affect any other projects.  Plus most (at least me) didn't understand how it was possible to get such accurate synchronization when the delays through the Internet mesh were so large and variable.   (I still don't).   But Dave thought it was possible, and that's why your computer, phone, laptop, or whatever know what time it is today.
> 
> Dave was responsible for another long-lived element of the Internet.   Dave's experiments were sometimes disruptive to the "core" Internet that we were tasked to make a reliable 24x7 service.  Where Dave The Scientist would say "I wonder what happens when I do this..." We The Engineers would say "Don't do that!"
> 
> That was the original motivation for creating the notion of "Autonomous Systems" and EGP - a way to insulate the "core" of the Internet from the antics of the Fuzzballs.  I corralled Eric Rosen after one such Fuzzball-triggered incident and we sat down and created ASes, so that we could keep "our" AS running reliably.  It was intended as an interim mechanism until all the experimentation revealed what should be the best algorithms and protocol features to put in the next generation, and the Internet Experiment advanced into a production network service.   We defined ASes and EGP to protect the Internet from Dave's Fuzzball mania.
> 
> AFAIK, that hasn't happened yet ... and from that article, Dave is still Experimenting..... and The Internet is still an Experiment.
> 
> Fun times,
> Jack Haverty
> 
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