[arin-ppml] Rationale for /22

[Ted Mittelstaedt]

Jon Lewis wrote:
> On Thu, 30 Jul 2009 bmanning at vacation.karoshi.com wrote:
> 
>> On Thu, Jul 30, 2009 at 01:56:43PM -0400, Leo Bicknell wrote:
>>> In a message written on Thu, Jul 30, 2009 at 12:19:19PM -0500, 
>>> George, Wes E [NTK] wrote:
>>>> To the question of "existing filters/inertia aside, is there a
>>>> justification for *any* minimum allocation size?"
>>>
>>> While it is a bit of a reductio ad absurdum argument, consider what
>>> (could) happen if the minimum were a /32.
>>
>>
>>     kind of like what happens when we give out everyone a /32
>>     of IPv6 space.  your arguments are identical for either
>>     an IPv4 or IPv6 /32.
>>
>>     and yet we find it acceptable to hand out /32's in one space...
> 
> The difference being, v6 is so much bigger than v4 

With IPv6 the host identifer portion of the address is 64 bits to
allow stateless autoconfiguration - essentially, using the MAC
address as the host ID.  THAT is why each subnet is so large.

It's a clever way to simplify and
get rid of DHCP servers and makes a huge amount of sense in some
instances.

Take a look at the following:

http://weblog.chrisgrundemann.com/index.php/2009/how-much-ipv6-is-there/
http://weblog.chrisgrundemann.com/index.php/2009/address_space-mac_v_ip/

As Chris says in the first link:

"...So, while there may be well over an octillion times more individual 
IPv6 addresses than there are IPv4 addresses; in terms of actual 
usability, IPv6 is only somewhere in the range of 16 million to 17 
billion times larger than IPv4.  Much larger, yes; infinite, no...."

Ted