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Re: 240/4

  • From: Alain Durand
  • Date: Tue Oct 16 13:53:37 2007

240/4 is tainted. The fact that some code exist somewhere to make it work is
good, but the reality is that there are tons of equipment that do not
support it. Deploying a large network with 240/4 is a problem of the same
scale as migrating to IPv6, you need to upgrade code, certify equipment,

Randy pointed out rightly, this is not only your network that needs
upgrading, this is all the networks who communicate with you that needs

So, classifying 240/4 as public use is unrealistic now and will remain
unrealistic in the near future.

Classifying it as private use should come with the health warning "use this
at your own risk, this stuff can blow up your network". In other words, this
is for experimental use only.

    - Alain.

On 10/16/07 9:42 AM, "Randy Bush" <[email protected]> wrote:

> vince,
> thanks for your presentation on 240/4.  i agree with it all.  two points
> do not hard-code address boundaries and special addresses, as we are
> likely to regret doing so.  two sub-lessons, ula and any other bright
> ideas.  "Those who cannot remember the past are condemned to repeat it."
> -- George Santayana
> my first thought on how to use it revolved around the idea that the
> devices inside my site are more diverse than those on the transit
> internet.  therefore, if i can use 240/4 internally, certainly we will
> all be able to transit it.  where this died was the realization that, if
> i want to transit 240/4, i am expecting all the devices in *your*
> network to be able to handle 240/4, which is not reasonable.  so i guess
> i come down on the private use side of the how-to-use decision.  i would
> be interested in hearing counter-arguments.
> again, thanks for the preso and the work.  and i presume my ciscos will
> soon be able to handle 240/4 at no additional hardware cost. :)
> randy

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