[arin-ppml] Fantasyland

Stephen Sprunk stephen at sprunk.org
Thu Aug 28 12:00:55 EDT 2008

michael.dillon at bt.com wrote:
>> OTOH, there are several large companies that have legacy As, 
>> which currently have no incentive to return them to ARIN.  
>> Many could renumber into a /16 or less, using NAT, if only 
>> they had the financial motivation to incur that cost; ditto 
>> for the hundreds of companies sitting on multiple Bs that 
>> could renumber into a /24 if motivated. 
> How many dollars would it take to convince a single company 
> to renumber from a /16 into a /24? Actual dollars please.

I'm not a business guy, so I have no idea how many dollars they'd find 
to be sufficient motivation.  However, I do know that the cost of 
renumbering is non-zero and the current incentive is zero; it doesn't 
require an MBA to know that no manager in their right mind is going to 
feel motivated under those conditions.

Heck, my own employer isn't even _using_ our B (we're RFC1918 
internally, NATed to PA /24s), but I know that management isn't 
interested in giving up that valuable "asset" for the $0 that we're 
currently offered.  I don't know how much they'd want, but it's 
certainly more than $0.

>> However, that still only buys us another year or two at current growth rates...
> Too true. Now consider the cost that this same company will incur to renumber into IPv6 two years after renumbering into a /24 using NAT. Can you justify this extra cost?

I don't predict that's how it will go, particularly since any large 
company is going to have loads of internal software that isn't, and 
probably will never be, IPv6-capable.  If/when they find that their 
external IPv4-only connectivity isn't sufficient, they will first enable 
NAT-PT on their existing NAT box.  After a few years, some bored geek 
will get around to deploying IPv6 internally, in parallel to the RFC1918 
IPv4 addresses, because he's sick of NAT-PT breaking some 
not-work-related app he's using.  Eventually, the IPv4 addresses will be 
taken out, perhaps with another NAT-PT box so IPv6-only users can access 
IPv4-only servers -- but that won't happen for at least a decade, maybe two.

> Why shouldn't the company in question just deploy IPv6 and
> install NAT-PT gateways to cover the next 2-3 years before
> IPv6 transit is widely available?

See above about internal apps not supporting IPv6.  Also, many companies 
still do not have network equipment that supports IPv6, and the 
management tools, reporting, internal training, etc. aren't there yet 
either even if all the equipment does nominally support IPv6.  If a 
handful of ISPs, whose core business is networking, can't get this 
right, how do you expect millions of businesses, who have a core 
business of making toothpaste or whatever, to do so?


More information about the ARIN-PPML mailing list