We've been using 10 minute lease times from the outset. The majority of our wireless subnets are /24 with some /23. I'd love to introduce some /22 but historical management of our address space has made obtaining contiguous space problematic. The annoying issue for me is that, at peak times, 20-25% of our IPs have been DHCP'd to devices simply because they are powered on with active radios. The users of these devices have no intention of actually using the wireless network.
James Savage York University Senior Communications Tech. 108 Steacie Building [email protected] 4700 Keele Street ph: 416-736-2100 ext. 22605 Toronto, Ontario fax: 416-736-5830 M3J 1P3, CANADA From: "Osborne, Bruce W. (NS)" <[email protected]> To: [email protected] Date: 10/01/2009 05:11 AM Subject: Re: [WIRELESS-LAN] wireless DHCP lease time Sent by: The EDUCAUSE Wireless Issues Constituent Group Listserv <[email protected]> Steve, We here at Liberty University tend to run 1 day lease times on our wireless network. Previous to our move to Aruba, we used /20s with fat 802.11b/g APs. I believe that the broadcast domain may have been some of the performance issue with our old system. We now use pools of /23 subnets. Since our controllers can handle 512 APs pr controller, we are currently running 16 /23 subnets in each pool. Bruce Osborne Liberty University From: Steve Hess [mailto:[email protected]] Sent: Wednesday, September 30, 2009 2:53 PM Subject: Re: wireless DHCP lease time 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) ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- ----------------------- Steve Hess Network Administrator Wheaton College Phone: 508-286-3404 Fax: 508-286-8270 ----------------------- ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
