RFC 29

RFC 29: Clocks, Milliseconds and a Little Bit of Drama 🎀

Robert Kahn from BBN wrote this one on 19 January 1970 🧚. It's an RFC-29 note under the Network Working Group. The original doesn't state a category or status, and it doesn't say it obsoletes or updates anything. It's a reply to Bill English's Request for Comments: 28 💜.

Intro vibes ✨

okay so bestie, this note is basically Robert replying to Bill's RFC 28 🫶. The big question it answers is about clocks ⏰.

The Millisecond Clock 🦋

A "millisecond" clock is good enough for most network measurements 💅. Like, honestly, it's giving "this is all you need." Round-trip message transit times are usually at least tens to hundreds of milliseconds 🌸, so a millisecond-level clock has plenty of room to work with.

The IMP has a 16-bit hardware clock 🔥 that ticks every 100 microseconds. It's there for timing internal events inside the IMP, for example while tracing 🙈. Iconic, right?

But here's the twist 😭: most measurements actually use a 25.6 ms. software clock 👑. So the hardware clock is the precise one for internal stuff, and the software clock is the everyday workhorse 💖.

Distribution 🌈

Everyone who got a copy of this note 💜:

A. Bhushan, MIT
S. Carr. Utah
G. Cole, SDS
S. Crocker, UCLA
K. Fry, MITRE
J. Heafner, RAND
B. Kahn, BBN
T. O'Sullivan, Raytheon
L. Roberts, ARPA
P. Rovner, LL
R. Stoughton, UCSB

That's the whole thing, bestie 🌈✨