In message <992DF93E-1EFB-4D68-BDD7-D5C7BE02FC01(_at_)americafree(_dot_)tv>,
I think that people here would be interested in (and likely
concerned by) the ARIN 2010-9 proposal :
"On 15 July 2010 the ARIN Advisory Council (AC) selected "IPv6 for 6rd"
as a draft policy for adoption discussion on the PPML and at the
Public Policy Meeting in Atlanta in October.
IPv6 for 6rd
6rd is an incremental method for Service Providers to deploy IPv6,
defined in the IETF Standards Track RFC 5969. 6rd has been used
successfully by a number of service providers to deploy IPv6 based
on automatic IPv6 prefix delegation and tunneling over existing IPv4
infrastructure. .... "
What worries me (and others) is that to give end
users an IPv6 /56 will generally require the assignments as short as /24s
to ISPs, due to the encapsulation of v4 addresses inside of v6 addresses :
"The 6rd prefix is an RIR delegated IPv6 prefix. It must encapsulate
an IPv4 address and must be short enough so that a /56 or /60 can be
given to subscribers."
56 - 32 = a /24
Only a naive deployment of 6rd would do this.
If you deploy a 6rd prefix per IPv4 prefix you have allocated and
set appropriate IPv4 mask lengths in your DHCP replies to the 6rd
option request then you have as many /56 as you have IPv4 addresses.
Round up to the next power of 2 and you have the amount of address
space you need to get from your RIR to support your 6rd deployment.
See RFC 5969.
Most ISP's IPv4 address allocations all fall within one or two /8.
That gives a /32 per containing 8 if you a IPv4MaskLen of 8.
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka(_at_)isc(_dot_)org
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