We've had some varying dhcp issues over various releases since 2007,
we've generally found a way to resolve. Upgrading drivers has helped,
but that's more been with individual client issues, not when you have a
number of clients on various OS's having similar issues.
We have had similar issues in the past where clients roam between AP's
on different controllers and changed the design of our network to reduce
roaming between controllers. So rather than having a building with 10
AP's where they are alternately connected to different controllers, the
whole building is connected to one. Due to the closeness of buildings
we've generally allocated buildings in close proximity to each other to
go to the same controller as well as neighboring buildings. Since then
(2 years ago) we've had only 3-5 reports a year on this issue, and
mostly due to someone mis-configuring primary's for access points. If
it's not mis-config then normally it's a neighboring building on
seperate controllers so we investigate AP locations, primary controllers
and radio power levels and modify the config as seems best.
We also had one controller playing up that would simply not provide dhcp
to about 90% of clients. After amount of un-successful troubleshooting
with TAC we decided (not their suggestion) to set the controller to
default and re-config it from scratch. It's been great ever since, we
hadn't just upgraded, and it was somewhere in 5.2.
Disabling dhcp proxy has also helped resolve a number of issues.
Perhaps not ideal solutions for everyone, but certainly has worked well
for us. We run 4404-100's and a mixture of 1131, 1231, 1250 and 1142 and
noticed no difference to clients on different AP types it's all referred
to controllers and roaming.
Jason
On 19/03/2010 5:18 AM, Lee Weers wrote:
No we are not running dhcp proxy.
Thank you,
Lee Weers
Central College
Assistant Director for Network Services
641-628-7675
*From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
[mailto:wireless-...@listserv.educause.edu] *On Behalf Of *Lee H Badman
*Sent:* Thursday, March 18, 2010 11:16 AM
*To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
*Subject:* Re: [WIRELESS-LAN] Client DHCP issues after WLC upgrade
Mike, and Lee- are you guys running DHCP proxy on your controllers?
-Lee
Lee H. Badman
Wireless/Network Engineer
Information Technology and Services
Adjunct Instructor, iSchool
Syracuse University
315 443-3003
------------------------------------------------------------------------
*From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
[mailto:wireless-...@listserv.educause.edu] *On Behalf Of *Schomer,
Michael J.
*Sent:* Thursday, March 18, 2010 11:40 AM
*To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
*Subject:* [WIRELESS-LAN] Client DHCP issues after WLC upgrade
Hello,
We are noticing a problem on our WPA/802.1x SSID with some of our
clients after a recent Cisco WLC upgrade from 5.2.178 to 6.0.188. The
clients are able to connect and authenticate to the SSID; however,
they aren't receiving an IP address. We have ruled out the DHCP
server as the problem. This doesn't affect all clients, and the
problem seems to come and go. We haven't seen a common OS or chipset
among the clients that are having problems.
We currently are running four WLCs in production, and all of them
received the upgrade at the same time. The only thing that most of
these clients have in common is that they are associated to APs on two
particular controllers. The only thing unique about those two
controllers is that they have mostly 1131 APs. When the clients roam
to a different WLC, they can usually connect just fine.
I'm at a loss right now. We did test the 6.0.188 code in one building
(with 1250 APs) for several months before deploying it, without any
notable issues. We are now potentially looking at downgrading back to
5.2 code, but aren't thrilled about it. Another option would be to
upgrade to 6.0.196, but we haven't done any testing of that code revision.
Has anyone seen a similar issue? Does anyone know of any issues with
6.0.188 code and 1131 APs? Any thoughts or advice would be appreciated.
Thanks for your help.
-Mike Schomer
-St. Cloud State University
********** Participation and subscription information for this
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********** 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/.
--
Jason Cook
Technology Services
The University of Adelaide, AUSTRALIA 5005
Ph : +61 8 8313 4800
e-mail: jason.c...@adelaide.edu.au
CRICOS Provider Number 00123M
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