[ih] ARPAnet Type 3 packets (datagrams)

[John Day]

I remember seeing text for both a "datagram" and 
Fast Select.  They may have been contributions. 
But I thought I remembered slightly more than 
placeholder text in the Orange book for datagrams.

And that something was put in under pressure but 
no one ever did it and it was taken out fairly 
soon.

But if it wasn't in the Orange book and it was 
taken out, when was it put in!?  ;-)

The only influence the researchers brought to 
that early debate (I think) was Louis convincing 
them to alight LAPB more closely to HDLC.

At 10:35 +0100 2009/11/26, Rémi Després wrote:
>Le 26 nov. 2009 à 06:34, Vint Cerf a écrit :
>
>>
>>  + remi despres
>>  +steve casner
>
>+ Barry Wessler
>
>>  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?
>
>The first X.25, published in 1976 in the CCITT 
>Orange book, had only virtual circuits (VCs).
>They were soon deployed in Canada (Datapac), in 
>France (Transpac), and the US (Telenet).
>
>Four years later, datagrams were introduced in X.25.
>They were only optional, while VCs remained mandatory.
>Quite different from IMP-to-IMP packets of 
>Arpanet and Internet datagrams, they had some 
>control by customers of packet drop conditions.
>
>In my recollection, they had been added under 
>political pressure from some administrations 
>that didn't operate X.25 networks.
>Four years later, as no X.25 operator had plans 
>to implement them, they were deleted from X.25.
>
>Regards,
>
>RD
>
>>
>>  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
>>>
>>
>>
>>
>>