Fyi Forwarding this from another list in case anyone encounters this
Sent from my iPhone Begin forwarded message: From: Robin Breathe <[email protected]<mailto:[email protected]>> Date: September 25, 2014 at 8:26:13 AM EDT To: <[email protected]<mailto:[email protected]>> Subject: Issues with recent Intel chipsets with 5GHz 802.11n Greenfield? Reply-To: Wireless Issues in the JANET community <[email protected]<mailto:[email protected]>> Afternoon all, We've recently identified an problem with the Intel Dual-Band Wireless-AC 7260 chipset (and likely other recent Intel Centrino chipsets), as found in a range of recent laptops, including the Dell Latitude E7740, leading to difficulty associating to our eduroam SSID followed by sporadic and recurring dropouts<https://communities.intel.com/community/tech/wireless> or all-out failure to associate and/or complete authentication. It seems we're not alone as Portsmouth also have a support page on the topic (http://ithelp.port.ac.uk/questions/385/Known+issues+connecting+to+the+wireless+network+(Eduroam)) where they appear to haven given up on getting devices with the 7260 to connect to eduroam at all, and others on the Intel forums seem to be having similar problems extending even to Linux clients. The latest Windows drivers (17.1.0) on Windows 7 at least appear to make no difference. Troubleshooting at our site, where we have a significant deployment of Aerohive APs offering eduroam over both 2.4G (802.11g/n clients only) and 5G (802.11n clients only) radios (gently band-steering to 5G), we have so far identified two workarounds. The first – truly vile – was to disable VHT/HT modes in the driver and so force 2.4G/802.11g operation in our environment. The second is simply unfortunate and involves configuring the driver to prefer the 2.4G band. The nature of both workarounds leads me to hypothesise that the root cause of issues with the latest Intel chipsets may be that their current drivers are not be coping with 802.11n Greenfield; having the client prefer 2.4G simply sidesteps the issue as its not in Greenfield mode. Has anyone else experienced these or similar problems with the latest batch of Intel chipsets (with or without 802.11n Greenfield), or have any alternate hypotheses as to the root cause of this behaviour? Has anyone else identified a superior workaround (short of disabling Greenfield mode)? Regards, Robin -- Robin Breathe Chief Technology Officer, OBIS, Oxford Brookes University – 01865 483685 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
