legacy /8

Paul Vixie vixie at isc.org
Sun Apr 11 15:57:53 CDT 2010

> From: David Conrad <drc at virtualized.org>
> Date: Sun, 11 Apr 2010 10:30:05 -1000
> > unless a market in routing slots appears, there's no way for the direct
> > beneficiaries of deaggregation to underwrite the indirect costs of same.
> And that's different from how it's always been in what way?

when 64MB was all anybody had, deaggregation was rendered ineffective by
route filtering.  what i've seen more recently is gradual monotonic
increase in the size of the "full table".  if the systemic cost of using
all of ipv4 includes a 10X per year step function in routing table size
then it will manifest as instability (in both the network and the market).

as you have pointed out many times, ipv6 offers the same number of /32's
as ipv4.  however, a /32 worth of ipv6 is enough for a lifetime even for
most multinationals, whereas for ipv4 it's one NAT or ALG box.  so, i'm
thinking that making ipv4 growth happen beyond pool exhaustion would be a
piecemeal affair and that the routing system wouldn't accomodate it
painlessly.  the rate of expansion of "other people's routers" seems to
fit the growth curve we've seen, but will it fit massive deaggregation?

> My tea leaf reading is that history will repeat itself.  As it was in the
> mid-90's, as soon as routers fall over ISPs will deploy prefix length (or
> other) filters to protect their own infrastructure as everybody scrambles
> to come up with some hack that won't be a solution, but will allow folks
> to limp along.  Over time, router vendors will improve their kit, ISPs
> will rotate out routers that can't deal with the size/flux of the bigger
> routing table (passing the cost on to their customers, of course), and
> commercial pressures will force the removal of filters.  Until the next
> go around since IPv6 doesn't solve the routing scalability problem.

instability like we had in the mid-1990's would be far more costly today,
given that the internet is now used by the general population and serves a
global economy.  if the rate of endpoint growth does not continue beyond
ipv4 pool exhaustion we'll have a problem.  if it does, we'll also have a
problem but a different problem.  i'd like to pick the easiest problem and
for that reason i'm urging dual-stack ipv4/ipv6 for all networks new or old.
Paul Vixie
Chairman, ARIN BoT

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