[address-policy-wg] FWD: [GLOBAL-V6] draft-narten-iana-rir-ipv6-considerations-00.txt

On Thu, Jul 14, 2005 at 02:47:26PM +0100, Niall Murphy wrote:
> Thomas, all,
> 
> > I'd welcome discussion/feedback on it, and this list seems as good a
> > place as any.
> >  
> > http://www.ietf.org/internet-drafts/draft-narten-iana-rir-ipv6-considerations-00.txt
> 
> This is nit-picking, but for the sake of clarity:
> 
> 2.7.  Utilization
> 
>    In IPv4, the utilization of a chunk of address space is defined as
>    the ratio of the actual number of host assignments to the theoretical
>    maximum number of host assignments. For example, a /24 in IPv4 can
>    number 256 hosts [...]
> 
> A /24 can't number 256 hosts; it can number 254.


	an IPv4 /24 is 192.0.2.0-192.0.2.255 or 256 discreate
	numbers.  subtract the all-ones and all-zeros..
		256-2 = 254...
	BUT ... wrap the /24 into a /22 and you -CAN- use the
	(apparent) zero & one nubmers are host assignments.
	the trick is in the mask and the placement of the "/24"
	in the overall announcement...

	you can't have an all-ones or all-zeros for the host.

> 
> Niall

--bill