Re: [Netdisco] subnet usage report

[Ivan B. <iva...@gm...>]

You pointed out a good possible flaw in my assumptions.

I would not bother to an high level of detail.
AFAIK, DHCP allocation (on NOT expired leases) on our DHCP servers is
done one a "lowest free ip address first".
Not checked documentation (they are mostly Microsoft),  but this is
what seems to happen.

This would give me a quite good (good enough for me) snapshot of used address.
And our wifi relies heavily on DHCP and REALLY SHORT LEASES :-)

I would check a 7 days arp count: long enough to keep track to weekly
peaks, and short enough to not contain too many allocated but not
currently used addresses.


My need is to check e.g. whether a /24 always contains no more than 40
address, and this would lead to a leaner /26.
We're consolidating our ip addressing to avoid overlap w/ other
departments, and we need to make a lot of capacity planning.

TIA


Ivan

On Thu, Apr 7, 2011 at 1:18 PM, Ingen Schenau, Jeroen van (ICTS)
<j.v...@ut...> wrote:
> Hi Ivan,
>
> On Thu, 2011-04-07 at 10:44 +0200, Ivan Brunello wrote:
>> I was asked to produce a report on ip subnet usage.
>> I would need something like:
>>
>> - subnet/mask
>> - size
>> - usage
>>
>> Since we're arpnipping device via netdisco, this would be a simple extraction.
>>
>> does Netdisco provide such info in a viable way, or should I become a
>> SQL guru in less than a week :-( ?
>
> Netdisco doesn't provide this yet, but as you point out, the relevant
> data for such a report is in the database.
>
> Just one question: how would you determine "usage"? In IPv4 subnets with
> regular changes in client population (eg wireless subnets), over time
> all addresses will have been used. Would you determine "usage" by
> counting the number of distinct IPs that have been active in the last xx
> days, or by some other method?
>
>
> Regards,
>
> Jeroen van Ingen
> ICT Service Centre
> University of Twente, P.O.Box 217, 7500 AE Enschede, The Netherlands
>
>
>