[arin-ppml] IPv4 is depleted today - unrealistic statements about IPv6 inevitability

Paul Vixie vixie at isc.org
Wed Sep 3 10:11:26 EDT 2008

[lee howard]
> http://www.arin.net/meetings/minutes/ARIN_XX/ppm1_transcript.html#anchor_7
> Look for "MR. LI".

[bill herrin]
> Robin and I have been working with Tony Li over on the Routing Research
> Group for the past year or so. He's a smart guy but his estimate is too
> low by at least an order of magnitude and possibly as much as two.

wouldn't any new technology already have to be on the price lists, if not
also actually shipping, in order to have any impact within the time frame
we're concerned about?

> The missing link is parallelism. Tony assumes we'll continue to compute
> 100% of all routes on each uniprocessor MIPS system as Cisco does today.
> On RRG, we've seen at least two viable methods of introducing useful
> parallelism in a BGP-based system at a sublinear increase in cost. They
> don't buy growth forever, but they buy a lot more than Tony thinks.

what are the scaling properties of that proposed design?  how many FIB and
RIB entries at what churn rate could we assume was reasonable in "tier 1"
after how many years from now?  will there be such a disconnect in the next
generation of routers that there will be no "hand me down" effect from the
current "tier 1" to edges, customers, and competitors?

does parallelism at the node level get us to the point where the speed of
light isn't enough for route propagation among the number of routes and
nodes we can have, and the whole thing gets to what reciprocating engine
people call "valve float" where convergence never occurs?

> > Routing does not scale to 4 billion routes.  Don't know exactly
> > where hardware can't do it anymore.
> Doesn't have to. As long as the /24 lower boundary on routability
> holds, IPv4 will stay on a logarithmic growth curve that flattens out
> somewhere around 7M or 8M routes.

why do you think a /24 is the lower boundary that "the market" would yield?

> ... In other words, IPv6 is not the only choice. ...

i'd like to discuss your antecedents further before arguing that conclusion.

note that if RRG has dissenting views, then someone who disagrees with tony
li's views from denver, could ask for a speaking slot in los angeles.  the
community ought to be open to well reasoned arguments from many perspectives.

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