[ih] ARPAnet Type 3 packets (datagrams)

[Bob Braden]

My memory was that BBN included type 3 (Uncontrolled or "raw") messages 
in the IMP protocol as an experiment, which they then considered too 
dangerous to use . BBN disabled them at (almost?) all hosts (almost?) 
all the time, I believe.  TCP/IP used standard reliably-delivered IMP 
traffic. But the facility must have been enabled for the packet voice 
experiments shown in that marvelous video.

My memory on this point is hazy, but probably Vint can correct me. When 
Barry Leiner became (D)ARPA Program Manager for the Internet research 
program, he became determined that BBN should try using Type 3 IMP-IMP 
packets for normal TCP/IP flows. He complained to the ICCB/IAB that BBN 
was resisting.  He insisted that the experiment be tried for 24 hours. 
Unfortunately I don't recall that the experiment ever happened;
it is more than possible that BBN stone-walled his demand.

Bob Braden
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