On 10/03/2012 09:52 AM, Seth Mos wrote:
Op 3-10-2012 18:33, Kevin Broderick schreef:
I'll add that in the mid-90's, in a University Of Washington lecture hall, Vint Cerf expressed some regret over going with 32 bits. Chuckle worthy and at the time, and a fond memory - K
"Pick a number between this and that." It's the 80's and you can still count the computers in the world. :)
Oops... And that was not quite what Mr Cerf meant to do.
I finally got around to finding a reply Vint Cerf wrote to a thread I started a year or two ago. The url is http://mailman.nanog.org/pipermail/nanog/2010-April/020488.html and quoted below in full for future prosperity. This gives a great behind the scenes view and a clear idea on the thought processes involved and why things evolved the way they did. Interestingly ipv6 is 128 bits, and I personally would have loved to see variable length address structures being implemented, alas. Maybe when ipv6 is in need of replacement... * Begin quote * Hi, Vint Cerf kindly sent through some more explanation. Regards, Mark. Begin forwarded message: Date: Sat, 3 Apr 2010 08:17:28 -0400 From: Vint Cerf <vint at google.com> To: Mark Smith <nanog at 85d5b20a518b8f6864949bd940457dc124746ddc.nosense.org> Cc: Andrew Gray <3356 at blargh.com>, NANOG List <nanog at nanog.org> Subject: Re: legacy /8 When the Internet design work began, there were only a few fairly large networks around. ARPANET was one. The Packet Radio and Packet Satellite networks were still largely nascent. Ethernet had been implemented in one place: Xerox PARC. We had no way to know whether the Internet idea was going to work. We knew that the NCP protocol was inadequate for lossy network operation (think: PRNET and Ethernet in particular). This was a RESEARCH project. We assumed that national scale networks were expensive so there would not be too many of them. And we certainly did not think there would be many built for a proof of concept. So 8 bits seemed reasonable. Later, with local networks becoming popular, we shifted to the class A-D address structure and when class B was near exhaustion, the NSFNET team (I think specifically Hans-Werner Braun but perhaps others also) came up with CIDR and the use of masks to indicate the size of the "network" part of the 32 bit address structure. By 1990 (7 years after the operational start of the Internet and 17 years since its basic design), it seemed clear that the 32 bit space would be exhausted and the long debate about IPng that became IPv6 began. CIDR slowed the rate of consumption through more efficient allocation of network addresses but now, in 2010, we face imminent exhaustion of the 32 bit structure and must move to IPv6. Part of the reason for not changing to a larger address space sooner had to do with the fact that there were a fairly large number of operating systems in use and every one of them would have had to be modified to run a new TCP and IP protocol. So the "hacks" seemed the more convenient alternative. There had been debates during the 1976 year about address size and proposals ranged from 32 to 128 bit to variable length address structures. No convergence appeared and, as the program manager at DARPA, I felt it necessary to simply declare a choice. At the time (1977), it seemed to me wasteful to select 128 bits and variable length address structures led to a lot of processing overhead per packet to find the various fields of the IP packet format. So I chose 32 bits. vint * end quote * -- Earthquake Magnitude: 4.7 Date: Monday, October 29, 2012 23:51:42 UTC Location: Flores region, Indonesia Latitude: -8.1762; Longitude: 123.4122 Depth: 19.60 km