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[ih] internet-history Digest, Vol 37, Issue 6

Just one problem with that memory Bob.

OSI didn't start until March,1978 and there was no network layer 
group until at least 1980.  (There was a lower layer group, but no 
group to develop protocols for the Network Layer).  There was no 
proposal within OSI for a subnet independent protocol, i.e. an 
internet protocol, nor an indication it wouldn't be IP until after 
83.  It wasn't even decided that the Europeans would allow datagrams 
into OSI in any form until Oct 1983.

Also, IEN 21 is dated January 1978.  The split must have occurred 
well before that because if *my memory serves* ;-) one of the 
discussions in arriving at INWG 96 by Dec 1977 was whether or not the 
protocol chosen could be used over something other than a datagram 
service and for TCP, IP already existed.

Lets not fall into the "effects of T.S. Eliot on Shakespeare" trap.  ;-)


At 16:42 -0800 2009/11/08, Bob Braden wrote:
>Vint wrote:
>  The first documented split of IP from TCP came with TCP v3 which 
>was   published as IEN21 in January 1978. The "internetwork header" 
>showed a   variable length (!) source and destination address field 
>among other   things, separate from the TCP header. This was 
>subsequently revised in   TCP 3.1 in Feb 1978  with IENs 26, 27, 28 
>and again, in June 1978 with   IPv4 and TCPv4 in IENs 40 (TCP) and 
>I recall rather vividly the variable vs fixed length address 
>discussion. Jon Postel and Danny Cohen strongly favored variable 
>length addresses, for architectural reasons.  I assume that Jon 
>slipped them into IEN21. In your DARPA role, you then decreed (and 
>it was perfectly clear to the rest of us that this was 
>non-negotiable) that addresses would be 32 bits and fixed length. 
>Your argument was that it would significantly simplify 
>implementations of the protocols, and that would strengthen the 
>acceptability of TCP/IP in the struggle with OSI. I have often 
>wondered who was right. In the short run, you were probably right 
>about the threat of OSI.  In the long run, would variable length 
>addresses have avoided the IPv4/IPv6 mess?  I can only speculate.
>Bob Braden