estimation of number of DFZ IPv4 routes at peak in the future

Wed Mar 9 05:43:48 UTC 2011

On Wed, Mar 09, 2011 at 12:44:05PM +0900, Randy Bush wrote:
> i am more of a pessimist.  i suspect that there will be enough v4-only
> destinations out there that multi-homed enterprises fronting onto 
> dual-stack backbones will announce teenie bits of v4 so they can nat64.

	I'll take this one a little further.

	I suspect that as we reach exhaustion, more people will be
forced to break space out of their provider's v4 aggregates, and
announce them, and an unfiltered DFZ may well approach the 'million'
entries some vendors now claim to support.

	Conveniently, we've given them enough ASes to do so, with
four byte support.  At least if our vendors get that working
correctly.

	If we get there, or even close (anything beyond 0.5M), I 
expect we'll see some of the native dual stack networks actually
acquire transport specifically for v6 and start running parallel
4/6 networks to deal with hardware forwarding limitations, particularly
those involving v6.

	Of course, I'd really, really, really love to be wrong here.
It'd be great if v4 traffic fell off quickly enough people wouldn't 
deagg for TE purposes, or v4 growth fell off, and a widespread 
forwarding problem could be avoided.

	--msa