[ih] UDP Length Field?

[Vint Cerf]

Bob Kahn might know, but my recollection is that they did not do "get a
block" "got a block" since they were single packet transmissions. No
retransmissions.
less clear about where they went in a queue to next hop.
v


On Thu, Dec 3, 2020 at 3:37 PM Jack Haverty via Internet-history <
internet-history at elists.isoc.org> wrote:

> Thanks, Steve, I vaguely remember that there were some highly restricted
> experiments reluctantly authorized, but not anything widespread.   E.g.,
> an obvious experiment would have been to use uncontrolled mode for all
> the core gateways and other gateways attached to ARPANET, but AFAIK that
> was never authorized.
>
> Also, I don't remember ever knowing in detail exactly how "uncontrolled"
> packets were actually handled by the IMP code, or what was experienced
> in any experiments that were done.   E.g., did uncontrolled packets "go
> to the front of the queue" bypassing normal traffic?  Did they interfere
> with other traffic, e.g., by preempting buffer space, or just get
> discarded when resources were unavailable?  In experiments, what were
> latencies, drop rates, et al like for UDP datagrams?   How did the
> ARPANET behave during such experiments?   Etc.
>
> /Jack
>
> On 12/2/20 4:33 PM, Stephen Casner wrote:
> > On Wed, 2 Dec 2020, Jack Haverty via Internet-history wrote:
> >
> >> There was an "uncontrolled mode" of operation possible within the
> >> ARPANET, which wouldallow a user computer to send packets bypassing all
> >> of the reliability mechanisms.   That could be used to deliver datagram
> >> Internet service.   However, the ARPANET managers (at DCA and BBN) were
> >> extremely reluctant to permit hosts (e.g., gateways) to use that mode,
> >> for fear that the uncontrolled traffic would crash the ARPANET.   I
> >> recall being involved in several "discussions" about using ARPANET
> >> uncontrolled mode for Internet experiments, but I don't remember any
> >> permissions ever being granted.
> > We definitely did get permission to use this for packet voice
> > experiments between ISI and LL, for example.  What I recall is that
> > initially we were required to arrange with BBN for a specific
> > experiment time between specific hosts and the uncontrolled mode (Type
> > 0, Subtype 3 -- BBN 1822 p. 3-17) would be enabled only for those
> > hosts.  But later I believe our packet voice hosts were enabled all
> > the time.
> >
> >                                                         -- Steve
>
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