[arin-ppml] IPv4 SWIP requirements (?)

[Owen DeLong]

> On May 25, 2017, at 21:02 , hostmaster at uneedus.com wrote:
> 
> This proposal was intended to try to bring the v4 and v6 world together on the same policy.  Because of the nibble boundary rule and rDNS, on the v6 side, there are really only 5 choices in network size: /48, /52, /56, /60 and /64 without having to do non-standard CNAME tricks used when subdividing the rDNS for more than one customer in a /24 of v4.

Actually, this isn’t true.

It just means _EXTRA_ NS entries.

For example, 2001:db8:beef::/48 can be delegated as f.e.e.b.8.b.d.0.1.0.0.2.ip6.arpa. as a single NS record set.

However, to delegate 2001:db8:beef:e000::/49, one needs two NS delegations:
	e.f.e.e.b.8.b.d.0.1.0.0.2.ip6.arpa.
and	f.f.e.e.b.8.d.b.0.1.0.0.2.ip6.arpa.

No CNAME requirement at all.

CNAME tricks would only come into play if delegating reverse for prefixes longer than /124. (Just as in IPv4, they only come into play longer than /24).

Owen