[arin-discuss] IPv6 End User Assignments

[Joe Maimon]

michael.dillon at bt.com wrote:

> You have a warped sense of size and waste. A /21 is hardly
> massive. With IPv4 I have received several /16 allocations
> from ARIN, and in IPv6, a /21 or /16 represents the same
> proportion of the total address space. 
> In the IPv4 world
> an ISP with a /21 is a small ISP in a single town. Waste
> is simply not an issue with IPv6.

This seems contradictory.

> It is not a waste of space. Very large ISPs in Europe and
> Asia already do assign /48s to each customer. ARIN policy
> allows it in North America as well.
> 

Only large ISP's can afford to do so with impunity. A /32 is not
sufficient for a default allocation of /48 per customer. That makes it
effectively only 16 times larger than an ipv4 /20, which suggests
additional prefixes or renumbering pain.

A /24 or /28 would be better if indeed /48 per customer is expected to
be the norm.

People are trying to carve up their allocated space now, in an
intelligent manner as much as possible. Getting it right at this point
could avoid pain later, so this is important.