[arin-ppml] ARIN-prop-127: Shared Transition Space for IPv4 Address Extension

Jack Bates jbates at brightok.net
Fri Jan 21 14:32:07 EST 2011

On 1/21/2011 12:22 PM, Owen DeLong wrote:
> You are running a much smaller network than many of these guys.
> They are planning to duplicate this /10 around their different network areas.

My point is that if they are large enough to utilize a /10, they 
probably already have much larger than a /10 in their network. Duping 
existing assignments would be just fine.

> To do this from existing space, you would basically need to turn off 2 regions and renumber
> all of the subscribers in one to match the addresses of the other. Then you would need
> to come up with additional addresses for all of the LSN/CGN boxes on the interior side
> and for the shared external addresses. I suppose you could use the addresses recovered
> from the second region, but, if your region contains more than 1,000,000 customers, it
> seems to me like it would be pretty difficult to do this juggling without significant down
> time.

The interior addressing would be an already existing network. It would 
also be the first network to undergo NAT444. That network can then be 
duplicated onto other networks.

> Instead, it's much easier to write up a use-case for the addresses you need for this
> and submit it to the RIR. Sure, probably nobody gets a /10 for this, but, not hard
> to imagine ways several /14s, possibly a few /12s, and certainly a number of
> /15s and /16s go out the door that way. If it goes that way, none of the ISPs have
> any incentive to share those intermediate addresses with the other ISPs and
> a few downsides to doing so.

If they ask, they'll be asking for the public facing addressing (which 
must be unique) while they work on renumbering the millions of internal 
addressing. The request for external addressing is much less.

> I think many providers are goint to hit the wall with need for NAT444 well before IPv6 is the mainstream protocol and not before we have run out of IPv4.

Perhaps, and they easily can use their existing addresses. The 
additional addressing you need is to cover the external side of the 
NAT444. Once that is established, you can renumber inside to heart's 
delight. Could be that you have multiple /8's worth of inside 
addressing. The NAT444 system isn't really going to care what's on the 
inside much.

The /10 shared won't work for the outside. People will request for 
outside facing addressing to deal with the transition to NAT444. The 
inside addressing can be anything, and as NAT444 is deployed, they can 
start replicating their entire address space.


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