[ih] nice story about dave mills and NTP

[Jack Haverty]

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