Using IPv6 with prefixes shorter than a /64 on a LAN

[owen at delong.com (Owen DeLong)]

On Jan 25, 2011, at 4:20 PM, Tony Hain wrote:

> Owen DeLong wrote:
>> ......
>> I suspect that there are probably somewhere between 30,000
>> and 120,000 ISPs world wide that are likely to end up with a /32
>> or shorter prefix.
> 
> A /32 is the value that a start-up ISP would have. Assuming that there is a
> constant average rate of startups/failures per year, the number of /32's in
> the system should remain fairly constant over time. 
> 
> Every organization with a *real* customer base should have significantly
> shorter than a /32. In particular every organization that says "I can't give
> my customers prefix length X because I only have a /32" needs to go back to
> ARIN today and trade that in for a *real block*. There should be at least 10
> organizations in the ARIN region that qualify for a /20 or shorter, and most
> would likely be /24 or shorter. 
> 
> As Owen said earlier, proposal 121 is intended to help people through the
> math. Please read the proposal, and even if you don't want to comment on the
> PPML list about it, take that useless /32 back to ARIN and get a *real
> block* today.
> 
> Tony
> 
> 
> 
> 
Unfortunately, it's hard for them to do that *today*.

That's the other thing proposal 121 is intended to do is help ARIN make
better allocations for ISPs.

Indeed, a key part of my quoted paragraph above was the "or shorter"
phrase.

Even in that scenario, though, I expect a typical ISP will use a /28,
a moderately large ISP will use a /24, a very large access provider
might use a /20, and only a handful of extremely large providers
are likely to get /16s even under the generous criteria of proposal 121.

Fully deployed, the current internet would probably consume less than
a /12 per RIR if every RIR adopted proposal 121. The 50 year
projections of internet growth would likely have each RIR invading
but not using more than half of their second /12.

Even if every RIR gets to 3 /12s in 50 years, that's still only 15/512ths
of the initial /3 delegated to unicast space by IETF. There are 6+ more
/3s remaining in the IETF pool.

Owen