I think the following would be interesting to share...
To recap - I found when I disable all 802.11N data rates on the Cisco
1602i, 1602e, or 1702i radios and force these client to use B/G, they
work as expected. Once I enable any MCS data rates the problem presents
itself. I think that proves the problem is related to 802.11N.
Knowing that I decided to do a packet capture on the crippled iPad 4th
generation. I noticed a trend of packets being retransmitted. In every
instance, the packets that were retransmitted are 11 bytes larger than
the packets that are not retransmitted. After close comparison I
noticed that all retransmitted packets include A-MPDU status in the
radiotap header. I just got done doing some testing tonight and found
that if I disable A-MPDU support on the controller, everything works
fine! I went ahead and disabled both A-MPDU and A-MSDU frame
aggregation for the 802.11b network until we have a resolution.
We experienced issues with Apple devices including iPad 3rd and 4th gen,
iphone 5c and 5s, and some Macbook Pros.
Thanks,
Dustin Howard
Network Support Specialist
Information Technology Services
Truman State University
100 E. Normal Ave.
Kirksville, MO 63501
Office - (660) 785-4165
Cell - (660) 341-7869
On 07/17/2017 04:44 PM, Dustin Howard wrote:
Thank you for you reply. I have tried a few different data rate
combinations including 12 mandatory and lower ones disabled. It
didn't seem to help.
Thanks,
Dustin Howard
Network Support Specialist
Information Technology Services
Truman State University
100 E. Normal Ave.
Kirksville, MO 63501
Office - (660) 785-4165
Cell - (660) 341-7869
On 07/17/2017 04:10 PM, Thomas Carter wrote:
How are your data rates configured? I seem to recall something about
Apple devices that used to be picky about it. We don't have Cisco,
but we have 12 as Mandatory and everything lower disabled for NG.
Thomas Carter
Network & Operations Manager / IT
Austin College
900 North Grand Avenue
Sherman, TX 75090
Phone: 903-813-2564
www.austincollege.edu
-----Original Message-----
From: The EDUCAUSE Wireless Issues Constituent Group Listserv
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Dustin Howard
Sent: Monday, July 17, 2017 3:28 PM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: [WIRELESS-LAN] Older Apple devices and issues with
802.11N(2.4Ghz)
I'm having an issue with some Apple devices and was wondering if
anybody has experienced similar or if you have a similar environment
and all is working well...
My environment is 5508 controllers (8.0.140.17) with 1600 series and
1702i APs. We have 1242 AP so cannot upgrade past 8.0..
I am having an issue with what seems to be only older Apple devices
on N(2.4Ghz). The devices authenticate/DHCP just fine but are very
slow and only seem to work for a few minutes until you have to
restart the wireless card. Loading a video is impossible...pings
timeout and have very high latency. Most the time the client cannot
even ping the gateway. I have been able to recreate this with iPad,
3rd and 4th Generations, an older Macbook Pro and an iPhone 5c while
using 1602i, 1602e, and 1702i APs. I haven't confirmed any other
brands having this problem.
The devices mentioned above work great if I disable the N data rates
on the AP radio. I had two users that were crippled with this issue,
so I disabled the N data rates for one building over the weekend.
The users said their devices worked great over the weekend. They
also work well on the 5Ghz band but we have areas that rely on the
2.4Ghz coverage. If this issue is not resolved before school starts,
then I'm afraid will have to disable N data rates globally for the
2.4Ghz band.
Appreciate any feedback!
--
Thanks,
Dustin Howard
Network Support Specialist
Information Technology Services
Truman State University
100 E. Normal Ave.
Kirksville, MO 63501
Office - (660) 785-4165
Cell - (660) 341-7869
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Constituent Group discussion list can be found at
http://www.educause.edu/discuss.
**********
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Constituent Group discussion list can be found at
http://www.educause.edu/discuss.
**********
Participation and subscription information for this EDUCAUSE Constituent Group
discussion list can be found at http://www.educause.edu/discuss.
