IPv6 Addressing Help

trejrco at gmail.com trejrco at gmail.com
Fri Aug 14 16:26:35 CDT 2009


"IIRC, RIPE allocated a /19 to France Telecom. Doesn't take more than a few hundred thousand allocations like that one to wipe out the IPv6 address space."

Do we expect a few hundred thousand places that need 2^29 (500M, give or take(OTTOMH)) /48s?  Didn't we _just_ get to seeing ~64k ASNs as a limiting factor?


/TJ
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: William Herrin <herrin-nanog at dirtside.com>

Date: Fri, 14 Aug 2009 16:52:42 
To: Jeroen Massar<jeroen at unfix.org>
Cc: Nanog<nanog at nanog.org>
Subject: Re: IPv6 Addressing Help


On Fri, Aug 14, 2009 at 2:40 PM, Jeroen Massar<jeroen at unfix.org> wrote:
> William Herrin wrote:
> [..]
>> I'm not aware of any way of dynamically assigning an IPv6 subnet to a
>> customer that's as well automated as IPv4 /32 dynamic assignment to a
>> DSL router with an RFC1918 NATed interior, but that may just be my
>> ignorance since I haven't needed to research it.
>
> DHCP-PD (prefix delegation)

Hi Jeroen,

Cool. So we'll have $100 CPE which uses it in a relatively idiot-proof
manner sometime between now and eternity.


>> Static IP customer: /60
>
> ARIN defines a /56 minimum. That is the reason that ISPs get a /32.
> RIPE defines a /48 at the moment.

ARIN "defines" a /64 minimum customer assignment and suggests /56.
They go on to say that, "RIRs/NIRs are not concerned about which
address size an LIR/ISP actually assigns."

See ARIN NRPM 6.5.4.1.  https://www.arin.net/policy/nrpm.html#six54


>> I recommend /60 as the customer default where most folks suggest /56
>> or /48. The IPv6 use profile looks a heck of a lot like the IPv4 use
>> profile and /60 is 16 subnets. How many of your customers find a
>> reason to use more than 3 IPv4 subnets, including their RFC1918 ones?
>> Relatively few.
>
> Think Future. And why bother with that anyway. If you as an ISP needs
> more address space just ring RIPE/ARIN/APNIC and ask for more, they will
> happily give it to you.

The future looks a lot like the past but with more blinking lights.
Seriously, I'm pretty nuts when it comes to networking. My basement is
AS11875, multihomed with about 35mbps of bandwidth. If I can't imagine
how *I* would use more than 16 subnets then it's a safe bet that many
years will pass before Joe random DSL customer wants to.

The world won't end, even if you assign every customer a /48. But why
be so grossly wasteful *before* anyone has demonstrated a practical
use for doing so?


> I guess you ran the numbers on how to run out of IPv6 address space?

IIRC, RIPE allocated a /19 to France Telecom. Doesn't take more than a
few hundred thousand allocations like that one to wipe out the IPv6
address space.

Regards,
Bill Herrin


-- 
William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004



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