Re: IP4 Space

[Owen DeLong <owen () delong com>]

On Mar 22, 2010, at 10:27 PM, Mark Newton wrote:

> On 23/03/2010, at 3:43 PM, Owen DeLong wrote:
> > With the smaller routing table afforded by IPv6, this will be less expensive. As a result, I suspect there will be 
> > more IPv6 small multihomers.
> > That's generally a good thing.
>
> Puzzled:  How does the IPv6 routing table get smaller?
Compared to IPv4?  Because we don't do slow start, so, major providers won't be
advertising 50-5,000 prefixes for a single autonomous system.

> There's currently social pressure against deaggregation, but given time
> why do you think the same drivers that lead to v4 deaggregation won't also
> lead to v6 deaggregation?
I think that the same drivers will apply, but, think of IPv6 as a Big 10->1
reset button on those drivers.  Sure, in 30 years, we may be back to
a 300,000 prefix table, but, in 30 years, a 300,000 prefix table will be
well within the hardware capabilities instead of on the ragged edge
we face today.

> (small multihomers means more discontiguous blocks of PI space too, right?)
Yep.  It does.  However, IPv6 gives us a 30-50,000 prefix table now (when
we get there) and 10-30 years to solve either the TCAM scaling issue or
come up with a better routing paradigm.

I think that eventually an ID/Locator split paradigm will emerge that is 
deployable. I think that SHIM6 and the others proposed so far are far
too complex and end-host dependent to ever be deployable.

Likely we will need to modify the packet header to be able to incorporate
a locator in the header in the DFZ and do some translation at the edge.
I haven't fully figured out the ideal solution, but, I think several others
are working on it, too.

Owen