Re: IPv10.

Bob Braden <> Sat, 12 November 2016 19:45 UTC

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Subject: Re: IPv10.
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From: Bob Braden <>
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Date: Sat, 12 Nov 2016 11:44:56 -0800
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Brian et al,

I have not been paying attention to this thread, but Brian's answer got 
my attention. I was in the room in 1977 when the decision was made to 
use fixed-length 32 bit IP addresses. I did not have a strong opinion at 
the time, but at least two members of the Internet research group, Jon 
Postel and Danny Cohen, strongly urged variable length IP addresses. As 
manager of ARPA's Internet Research program, Vint Cerf made the call for 
fixed length addresses. His argument was that if we were to have any 
hope that the DoD might accept the experimental protocols, TCP must not 
be too complex to program. He thought that variable-length addresses 
would scare off our possible customers.

Incidentally, the OSI folks did adopt variable -length network 
addresses; this was one of the advantages of OSI that later led the IAB 
to suggest that the Internet shou ld consider adapting the OSI 
protocols. Which caused the famous Kobe lynching of the (original) IAB.

Good heavens, 1977 was 40 years ago!

Bob Braden

for a problem, that is IMHO not very clearly,

>> how about ipv4 and ipv6 are incompatible on the wire and this
>> has created a multi-decade ipv6 charlie foxtrot?
> Yes, I suggest mentioning that to Vint, Bob and a few others in 1977,
> so that they can design IPv4 with extensible addresses. People in
> 2016 will be grateful.
>     Brian