Re: [v6ops] ULA draft revision #2 Regarding isolated networks

[Philip Homburg <[e-mail]>]

In your letter dated Wed, 28 May 2014 16:24:59 +1200 you wrote:
>I understand the problem. Users are idiots, including us when we
>act as users. I am not arguing that ULAs will prevent all operational
>problems caused by private addressing. I am only arguing that there will
>be private addressing and that ULAs will cause fewer problems than
>RFC1918-for-IPv6 would.

Maybe we can keep a bit of context around what scenario we are talking about.

Say:
1) Small organisation, doesn't get PI space, has to renumber when moving to a different
   ISP. The IPv4 solution is to use NAT. Maybe we can do better for IPv6. Probably
   collisions of ULA space during a merger are not a big deal.
2) Bigger organisation, does have PI space and has a more or less homogenous network.
   No real need for ULA.
3) Big organisation, wants to have a secret network that only communicates through
   application layer gateways. Should be able to pick a proper ULA if they need one.
   Otherwise, though luck. No real need for ULA. It may make source address selection
   a bit easier, but that is only a small part of the puzzle.

I think the only interesting case is 1). Whether or not we make renumbering easy enough
that they don't do NAT is an open question. A large part of that is in software
configuration: is it possible to store the current prefix in such a way that software
can easily pick it up.