Exponential Lease Time

Nicholas F Miller nicholas.miller at Colorado.EDU
Thu Sep 6 15:03:36 UTC 2012


I think you may have cracked it. Some initial testing shows it working as expected.
_________________________________________________________
Nicholas Miller, OIT, University of Colorado at Boulder




On Sep 5, 2012, at 8:52 PM, Glenn Satchell wrote:

> This is going to increment on every packet from the client, so perhaps you
> need to test for the request-type using option dhcp-message-type. See
> dhcp-options man page for possible values. Perhaps only increment on
> DHCPREQUEST type? So a big if statement around the sections that increment
> renewal.
> 
> if option dhcp-message-type = 3 {
>  if renewal = 3 {
>    ...
>  }
> } else {
>  default ....
> }
> 
> regards,
> -glenn
> 
> On Thu, September 6, 2012 2:31 am, Nicholas F Miller wrote:
>> Here are some observations from my testing. The results are not consistent
>> enough to be used in production but it is still pretty interesting.
>> 
>> 1) I haven't seen one lease that had a renewal = 1. They all seem to start
>> with a renewal = 2 (Windows and Mac clients, wired and wireless). This may
>> be a result of using helper addresses on the routers and WISM2s.
>> 2) iPhones seem to jump straight to the longest lease time (if renewal =
>> 3).
>> 3) Windows phones jump straight to the second longest lease time (if
>> renewal = 2).
>> 4) Android phones behave the same as Windows and Mac clients.
>> 
>> Here are the values I used for my testing which were defined in the pool
>> statement:
>> 
>>        if renewal = 3 {
>>                default-lease-time 86400;
>>                max-lease-time 86400;
>> 
>>        } elsif renewal = 2 {
>>                default-lease-time 14400;
>>                max-lease-time 14400;
>>                set renewal = 3;
>> 
>>        } elsif renewal = 1 {
>>                default-lease-time 3600;
>>                max-lease-time 3600;
>>                set renewal = 2;
>> 
>>        } else {
>>                default-lease-time 900;
>>                max-lease-time 900;
>>                set renewal = 1;
>>        }
>> 
>> _________________________________________________________
>> Nicholas Miller, OIT, University of Colorado at Boulder
>> 
>> 
>> 
>> 
>> On Aug 31, 2012, at 2:42 PM, Norman Elton wrote:
>> 
>>>> Out of interest, does processing that sequence of statements create
>>>> more or
>>>> less load than just processing renewals without dynamic lease lengths ?
>>> 
>>> Definitely deserves further testing. We've done some scripting before
>>> and it didn't contribute to a noticeable load.
>>> 
>>>> Also, when the lease expires, does "renewal" stay set or does it get
>>>> removed
>>>> from the lease record ?
>>> 
>>> After the lease expires, it appears that the "renewal" variable gets
>>> wiped. Again, this could use some more testing.
>>> 
>>> I pretty much hacked this up. I'd love some feedback from folks who
>>> are more familiar with how the variables work and are designed to be
>>> used.
>>> 
>>> Norman
>>> _______________________________________________
>>> dhcp-users mailing list
>>> dhcp-users at lists.isc.org
>>> https://lists.isc.org/mailman/listinfo/dhcp-users
>> 
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>> 
> 
> 
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