The Choice: IPv4 Exhaustion or Transition to IPv6

Iljitsch van Beijnum iljitsch at
Thu Jun 28 22:11:35 UTC 2007

On 28-jun-2007, at 21:55, Steven M. Bellovin wrote:

> More precisely, I don't see any reason why it would take significantly
> less.  In fact, it can't take much less, no matter what.  Figure two
> years for the basic design, 3-5 years for the IETF (or whomever) to
> engineer all the pieces (it's more than just the IP header, and until
> we have a new design we won't even be able to start identifying the
> pieces), 3 years for design/code/test (in the NANOG world, that
> includes new ASICs, line cards, etc.), and 3-5 years for much existing
> gear (routers, end systems, etc.) to be replaced with the IPvN stuff.
> That adds up to 11-15.

That assumes that the next next IP will be as different from IPv6  
(and IPv4) as IPv6 is from IPv4. I don't think that's necessary. Most  
of the complications in the IPv4->IPv6 transition come from the fact  
that addresses are now 128 bits long where they used to be 32 bits  
long. If the new protocol also uses 128 bit addresses, all the stuff  
that lives at layer 4 and above can probably be fooled into thinking  
that it's talking IPv6 while the packets are actually IPv9.

Sure, IPv6 isn't the best design we could have, but it's good enough  
and until we can agree on address policies that make more sense than  
"everyone with a few thousand dollars/euros to spend can get a seat  
at the top of the routing hierarchy", we should probably steer clear  
of inventing new IP versions.

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