IP4 Space - the lie

Suzanne Woolf woolf at isc.org
Fri Mar 5 09:21:53 CST 2010

On Fri, Mar 05, 2010 at 12:39:19PM +0000, bmanning at vacation.karoshi.com wrote:
> 	er... what part of dual-stack didn't you understand?
> 	dual-stack consumes exactly the same number of v4 and v6 addresses.
> 	if you expect to dual-stack everything - you need to look again.
> 	either you are going to need:
> 	lots more IPv4 space
> 	stealing ports to mux addresses
> 	run straight-up native IPv6 - no IPv4 (unless you need to talk to 
> 	a v4-only host - then use IVI or similar..)
> 	imho - the path through the woods is an IVI-like solution.

There are several IPv4/IPv6 co-existence technologies under
development that attempt to resolve the asymmetry Bill notes here,
where IPv4 addresses are already scarce and IPv6 addresses may
reasonably be treated as less so. They include IVI, NAT64/DNS64, and
dual-stack lite.

See for example the lightning talk last Wednesday in Austin on AFTR,
ISC's free, open source implementation of dual-stack lite, or the
panel discussion at APRICOT earlier this week.

It's only been in the last couple of years that the IETF and the
vendors have been taking seriously the problem of moving IPv4-IPv6
co-existence mechanisms into the network, away from host-based
dual-stack and into use cases where legacy infrastructure has to
co-exist with the need for growth. But now that they have, there's an
embarrassment of what we can hope turn out to be riches in this
area....or at least a pony amongst the, err, bulk of material.


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