[openstack-dev] [api][neutron] Best API for generating subnets from pool

Carl Baldwin carl at ecbaldwin.net
Mon Mar 23 22:45:28 UTC 2015

On Mon, Mar 23, 2015 at 4:23 PM, Kevin Benton <blak111 at gmail.com> wrote:
> How would you represent that you want the last address in a /26 network if
> you don't know what address range you are getting? That seems
> pretty confusing when the resulting address turns out to be
>>It isn't a new concept to think about the network and host parts of an IP
>> address separately.
> Definitely, but with small subnets like the example above, it is impossible
> to know the absolute numbers for the host portion of the address.
> It's about setting the right expectation for the caller. Specifying
> '' implies the caller is going to get something back that ends in
> '63', which is only true some of the time. By using 'ip_index', I was trying
> to convey that you are getting something counted from the start of whatever
> is chosen, rather than getting a specific address ending.

I see what you're saying but it still doesn't do it for me.  To me, didn't say that I'd get something ending in .63.  I know that
I can get something ending in .127, .191, or .255.  Also, I don't
think that a raw integer like 63 would do any better at setting the
expectation.  I bet the same users who would be surprised by one would
be surprised by the other.  My vote would still be to use the
dotted-quad notation.

When working with ipv4 addresses, one must understand that the address
is a 32-bit number.  Dotted quad is just the familiar format for
seeing them but, no matter the format, the concept is the same.  The
same is true for the host part.


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