[ih] Origin of "best effort"

[Brian E Carpenter]

I learnt very early on that the Internet offered a "best effort" service
for the delivery of datagrams.

Where did that meme come from, and when?

The earliest trace I found in a quick trawl was 1986 (RFC992). But RFC791
doesn't mention it, and defined TOS, such that all packets were *not* assumed
to be created equal. The 1984 Saltzer et al paper doesn't mention it either.

(RFC768 does say that UDP delivery is "not guaranteed" but that is not
the same thing as "best effort".)

The question is of interest because some analyses of network neutrality,
including a student dissertation I was reviewing yesterday, conflate the
end-to-end principle with best-effort packet delivery.

Regards
     Brian