Not sure if this is the case for anyone, but one of the issues we
ran into with lease shortages was related to maybe on oversight on our
part. The ISC dhcp has a max-lease-time and a default-lease-time
value. While wireless was set to hand out 30-minute leases (default-
lease-time), the max-lease-time globally was set to 24 hours. We had
a /22 that was being fully consumed by 9:30AM each weekday, and were
seeing leases through the night, that, when cleared, wouldn't be
renewed until the next morning. With Windows OSes, they took the 30-
minute lease and went on their way. Apple devices request a 90-day
lease, and so were being handed out a 24-hour lease, since that's what
the max-lease time was set to. We shortened the default and max-lease
times down for the wireless dhcp config to 15 minutes, and now run
with 40-50% of available leases free through the day for the /22.
--
Richard
On Sep 30, 2009, at 3:33 PM, Philippe Hanset wrote:
What a timely discussion!
This morning we noticed that our pools (Aruba VLAN pools, 32* /24)
were being filled from 70 to 90%.
Our lease time is 3 hours. As most of you, we have been hammered by
Iphone/Ipod-touch (~4000 registered at the moment)
For a campus population of 30,000 (25,000 students 5000 fac/staff).
Has anyone seen issues with 30 or 40 minutes DHCP leases on an Aruba
infrastructure ?
(we don't run DHCP on Aruba, but on ISC DHCP)
What AAA timeout have you implemented? (show AAA timers... in our
case we have 1800 sec)
(we had to shorten the AAA timeout as well because our User licenses
were being exhausted
... Iphone again ;-)
Thank you
Philippe Hanset
Univ. of TN
On Sep 30, 2009, at 2:52 PM, Steve Hess wrote:
We run 4 /23's (one per class) with 4 day lease times. It's very
tight right now for freshmen and sophomore's but lots of room for
juniors and seniors. Each class is about 350-450 students. I'm
looking to add another /23 per class to provide some head room. We
run 4 day lease times for the forensic aspect of it.
Definitely seeing more wireless devices this year. Upperclassmen
are registering computers. Underclassmen are registering a
computer (or two), an iPhone/iPod, and a gaming device. For those
of you running the /22's and /20's, you don't see performance
issues with broadcast domain's that large? Our wireless vendor
(Alcatel/Aruba) highly suggested shrinking the broadcast domain (we
had been running one /22 for all students).
Steve
heath.barnhart wrote:
We run 30 minute leases for most of SSIDs, no problems. We saw an
unexpected boost in wireless usage this semester though, and had
to go from /22 networks to /20 to accommodate the new users and
leave room for expansion.
Heath
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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--
-----------------------
Steve Hess
Network Administrator
Wheaton College
Phone: 508-286-3404
Fax: 508-286-8270
-----------------------
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********** Participation and subscription information for this
EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/
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**********
Participation and subscription information for this EDUCAUSE Constituent Group
discussion list can be found at http://www.educause.edu/groups/.
