Re: US DoD and IPv6

[Dave CROCKER <[e-mail]>]

On 10/10/2010 2:51 PM, Steve Crocker wrote:
> A compatible solution would have been better, but I don't think IPv4... --
> were designed in a way that permitted a compatible extension.


Oh?

Perhaps:

    1.  Adopt an IPv6 as Steve Deering originally designed it[1]:  A basic 
upgrade to the IPv4 header, with more address bits, an extensibility mechanisms 
for adding fields later, and removal of some bits that weren't needed.

    2.  Define the IPv6 address space as the IPv4 address space, with all zeroes 
for the higher bits.  (In other words, defer more interesting schemes until later.)

    3.  Design header translation devices to map between the two formats.

    4.  Start fielding these implementations.  (That could have started by 1994 
or so.)

The "gateways" between v4 and v6 would initially be notably for having almost no 
work to do and of not losing any information.  In particular, barely qualifies 
as a "dual" stack.

With this approach, "incompatibility" between v4 and v6 would only occur when 
additional addresses, beyond v4's limitations, start to be assigned.

We must deal with the current reality and make it work, but historical 
considerations need to factor in the ambitions that dominated during the many 
years of design.

The community got ambitious in a fashion that smacked of the overreaching that 
is often called second system syndrome (although counting the Arpanet, this was 
really a third system...)

d/

[1]  http://tools.ietf.org/html/draft-deering-sip-00
-- 

   Dave Crocker
   Brandenburg InternetWorking
   bbiw.net