[ih] ARPAnet Type 3 packets (datagrams)

[Vint Cerf]

+ remi despres
+steve casner

John, I am pretty sure that X.25 did not have datagrams in the same  
sense as Cyclades/Cigale or even ARPANET. There was a fast select but  
I thought it came later rather than earlier in the X.25 story?

v

On Nov 25, 2009, at 7:14 PM, John Day wrote:

> Yea, that jibes with my recollection.
>
> And "datagrams" were in the first version of X.25 in 76, or was that  
> Fast Select?
>
>
> At 18:45 -0500 2009/11/25, Vint Cerf wrote:
>> the type 3 packets were explicitly used for real-time packet voice  
>> and later packet video experiments. This would have been in the  
>> 1975 time frame (but Danny Cohen and Steve Casner would know for  
>> sure as they were at ISI; Lincoln Labs was also involved and we  
>> used their packet digitizers/compressors. Duane Adams managed the  
>> packet voice activity during the time I was at DARPA so I am  
>> copying him too. I don't seem to have steve casner's email but I  
>> think he is now at PARC.
>>
>> vint
>>
>>
>>
>>
>> On Nov 25, 2009, at 6:05 PM, Richard Bennett wrote:
>>
>>> I've discussed this issue recently with a key member of the IMP  
>>> team at BBN and he (unsurprisingly) has a very different  
>>> recollection of the facts. A datagram mode was added to the IMP  
>>> and to X.25 switches fairly early. Datagrams appeared on research  
>>> networks well before TCP/IP was defined; CYCLADES had them in 1972.
>>>
>>> The BBN people have not been able to tell me whether the NWG ever  
>>> took advantage of the datagram mode in the IMP; that was outside  
>>> their department.
>>>
>>> RB
>>>
>>> Bob Braden wrote:
>>>>
>>>> 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
>>>> '
>>>>
>>>
>>> --
>>> Richard Bennett
>>> Research Fellow
>>> Information Technology and Innovation Foundation
>>> Washington, DC
>