Re: ISP customer assignments

[William Herrin <herrin-nanog () dirtside com>]

On Mon, Oct 5, 2009 at 11:27 AM, Brian Johnson <bjohnson () drtel com> wrote:
> From what I can tell from an ISP perspective, the design of IPv6 is for
> assignment of a /64 to an end user. Is this correct? Is this how it is
> currently being done? If not, where am I going wrong?

No. A /64 is one *subnet*. Essentially the standard, static size for
any Ethernet LAN. For a customer, the following values are more
appropriate:

/128 - connecting exactly one computer. Probably only useful for your
dynamic dialup customers. Any always-on or static-IP customer should
probably have a CIDR block.

/48 - current ARIN/IETF recommendation for a downstream customer
connecting more than one computer unless that customer is large enough
to need more than 65k LANs.

/56 - in some folks opinion, slightly more sane than assigning a 65k
subnets and bazillions of addresses to a home hobbyist with half a
dozen PC's.

/60 - the smallest amount you should allocate to a downstream customer
with more than one computer. Anything smaller will cost you extra
management overhead from not matching the nibble boundary for RDNS
delegation, handling multiple routes when the customer grows, not
matching the standard /64 subnet size and a myriad other obscure
issues.

Regards,
Bill Herrin


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