We use a pool of 8000 addresses for a peak usage of 5000 users at a time
(and we're already needing to expand the available address pool), we
also use NAT to avoid wasting too many public addresses. The only issue
i'd see you running into with such a short lease time are users whose
machines cache the dhcp address and attempt to reclaim the same address
and sometimes have problems (i think this is/was an issue with some
macbooks?) I believe it's a bug with DHCP addresses remaining bound and
causing IP conflicts. With such a short lease time and a small available
pool, this would aggravate this bug.
I'd recommend just adding additional address space and keeping a
reasonable (1-hr/class period) lease time, most users tend to come to
class, get on the wireless, get off when class ends, and then they'll
just transition to a new class and get back on the wireless immediately,
or they're done and are gone for the day.
-Justin
Garrett Harmon wrote:
We're running into some issues at the ramp up of a quarter with our
DHCP lease time attempting to utilize the /24's we currently pool for
our main essid. We moved from 1hr. to 30 minutes, but are still
running out of leases occasionally. For instance, we have 160 users in
a /24, but due to the transient nature of wireless/classes leases that
are used for a brief moment the cycle isn't quite efficient enough.
What is everyone else using for wireless DHCP lease times? I know I
can just add another /24 to the pool, but the networks are not being
utilized enough. We want to try 15 minutes but are wondering if we
will start to run into issues related with that? Your input is greatly
appreciated!!
*Garrett Harmon*
Network Engineer
Office of Information Technology
The Ohio State University
614.292.2122 (o)
614.747.5539 (c)
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--
Justin Hao
Network Engineer
Texas A&M University
Networking and Information Security
[email protected]
(979)862-2162
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