[ietf78-tech] Impact of long leases on IPv4 DHCP address ranges for wireless

[John Kemp]

Uh... I thought the design goal was: login either 1 time , or at worst
1 time a day.

/jgk

Sent from my iPad

On Jul 8, 2010, at 6:28 PM, Bill Jensen <wej at doit.wisc.edu> wrote:

> At the risk of missing the point here, I would suggest not deviating 
> from our "normal" lease times for a heavy AP environment.
> 
> If the hope was to assist captivator behavior, I will claim its 
> unnecessary.  Running long lease times is fine but running short leases 
> is also fine.  (We have certain AP subnets at UW-Madison where leases 
> are cranked down to around 15 minutes to shed transient hosts that 
> obtain addresses - such as when hundreds of students are moving about 
> during class change.)  If there is concern about ip*tables growing 
> larger, we have two things working in our favor.  1) There are automatic 
> and manual methods to flush rules associated with inactive flows or all 
> rules, 2) historically we have never reached a client count that poses a 
> serious performance risk short of a possible scenario where every client 
> appears on a single vlan.
> 
> Thoughts?  :-)
> 
> -wej
> 
> On 7/8/10 6:06 PM, Chris Elliott wrote:
>> On Jul 8, 2010, at 6:54 PM, Jim Martin<jim at daedelus.com>  wrote:
>> 
>>>    Running out? It's a /16 :-)
>>> 
>>>    We usually tend to live in the lower /17, so we should be fine.
>> 
>> Of course. But I'm talking about our VLAN configuration.
>>> 
>> 
>>>    - Jim
>>> 
>>> On Jul 8, 2010, at 6:50 PM, Chris Elliott wrote:
>>> 
>>>> All,
>>>> 
>>>> Are we going to need to expand our v4 DHCP address ranges and probably also our subnet sizes because we are planning on much longer DHCP leases to support authentication?
>>>> 
>>>> I haven't done the math and I don't know if we have any data on how close we have come to running out, with the exception of Anaheim when Swisscom mistakenly assigned a DHCP range for a /24 subnet for the wireless VLAN.
>>>> 
>>>> Chris.
>>>> 
>>>> 
>>>> --
>>>> Chris Elliott
>>>> 
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>>> 
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> 
> -- 
> Bill Jensen, Network Engineer
> UW-Madison DoIT Network Services
> 1210 W. Dayton St., Madison, WI  53706
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