[ih] nice story about dave mills and NTP

[Louis Mamakos]

On 2 Oct 2022, at 15:50, Brian E Carpenter via Internet-history wrote:

> I think that's why IPv6 never even considered anything but a hop count.
> The same lies behind the original TOS bits and their rebranding as
> the Differentiated Services Code Point many years later. My motto
> during the diffserv debates was "You can't beat queueing theory."

The IPv4 TTL being a hop count is what enabled one of the most essential
and effective debugging tools for the public Internet: traceroute.  Sure
and eventually killing off looping packets for those routing loops that
don't ever happen, the ones we'd use traceroute to discover..

What's interesting these days is that some network elements actually do
have very precise means to measure how long a packet is queued between
the ingress and egress interface; it's there to support PTP.  Which sort
of brings this back around to the Mills and his NTP.

I think the article got it a little wrong; the genesis of NTP was the
HELLO routing protocol the fuzzball used.  It was a distance vector
routing protocol that did minimum delay routing to the destination.
Eventually, it got pulled out into NTP.  Other fun fact:  the first
NTP RFC was the first (also) published in PostScript, so you could
more fully enjoy the mathematics.

I ended up implementing HELLO for an IP stack I wrote for a UNIVAC 1108,
coincidentally as a class project for a "Special Topics in Networking"
Mills taught at the University of Maryland in the early 1980's while he
was still as Linkabit, before going to UDEL.  That was the start of a
small Fuzzball infestation at UMD for some year, eventually including
a stratum-1 NTP clock.  I'm sure that I was of many who's career was
directly influenced by Dave, and I have really fond memories of a couple
of classes he taught, and later work with him.

Louis Mamakos