> Keith Moore writes:
>  > > Quick question - you have been nay-saying on local-use addressing
>  > > for as long as I can recall, but do you truly have an alternate
>  > > proposal that will work for intermittently-connected/disconnected
>  > > sites, 
>  > 
>  > disconnected sites - should use some sort of PI space - either
>  > globally-unique or probably-unique
> 
> So I have a question: what does "disconnected"
> really mean?  Does it mean people who do not have
> any internet access whatsoever and never will? 

IMHO a truly disconnected network would have no connectivity to any
other net, at least at the present time.  If such a network were to
acquire Internet access it should renumber, much as if it were a site
moving from one ISP to another.

there's another useful category of site that has no connectivity to the
global/public Internet but does wish to connect to other sites, some of
which might connect to the global/public Internet.

> Or
> does it mean people who want parts of their
> network to be either physcially or through
> firewalling to be disconnected from some or all of
> the net?

no, it doesn't mean that.  of course if you want an entire network to be
isolated you can treat that as a disconnected network.  but usually you
want to allow some degree of external access to or from some of the
hosts on the network. if you do that, you should have global addresses
for all of those hosts even if you filter traffic to and from most of
them. otherwise you can't really expect apps to work between the
"privileged" hosts and the"unprivileged" ones - especially if those apps
also involve external hosts.

> If it's the former, maybe I'm heretical but do we
> really much care? 

yes, because isolated v4 networks that picked an arbitrary prefix and
then later connected to the rest of the net did cause and experience
problems.  we want them to be able to make a smooth transition.  also,
some networks that lack connectivitity to the global internet will still
want to interconnect with other networks.

> If it's the latter... a /48 gives 16 bits of
> subnets. Surely that's enough to carve out a
> network or two for their disconnect networks. And
> even if they changed providers... so what?  If
> it's a disconnected network using the old prefix
> certainly doesn't _hurt_ anything until... you
> want to connect it, but if you want to connect a
> disconnected network you needed to renumber
> anyway!

not true.  in order to understand whether there's a potential
address conflict you need to consider the transitive closure of all
connections available to all hosts on the network.  if the same address
refers to different hosts anywhere in the network then it can still
cause problems for apps doing referrals even if the meaning of that
address is well-defined for every individual host.

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