Notes on IT (mainly Microsoft)

Microsoft Windows 8 and Cisco Wireless LAN Controller incompatibility

with 2 comments

During the Windows 8 beta and preview program, a colleague and I did some detailed testing of new features in Windows 8 wireless networking particularly around the new EAP-TTLS support. We found some issues which Microsoft fixed, however  one problem we found, unrelated to EAP-TTLS, was with certain Broadcom wireless NICs failing to connect to our Cisco wireless network (Lightweight APs with central wireless LAN controllers CUWN). We filed a bug and provided detailed debugging but were disappointed to find the issue still present in Windows 8 RTM. It now seems to be the case that the issue was not with the Broadcom wireless NICs per se, but with the fact that the Broadcom drivers in Windows 8 are Windows 8 logo certified and implement 802.11w (Management Frame Protection) and that it transpires that Cisco wireless LAN controller software has problems in this area, an 802.11w-capable client cannot connect to an SSID on Cisco (controller-based) CUWN using WPA or WPA2 key management with AES encryption, see here for an explanation from Cisco and their official announcement here.

See this //Build conference presentation for Windows 8 wireless networking and particularly the Appendix of the slide deck for more 802.11w in Windows 8 logo certification.

UPDATE: There are now versions of the 7.0, 7.2 and (new) 7.3 cisco software trains that have fixes for the bug (CSCua29504).

UPDATE: A KB article from Microsoft covering this problem is here.

UPDATE: Having now seen a number of Windows 8 clients connected to Cisco wireless networks running controller software that fixes the 802.11w issue, we have found some clients running Broadcom wireless NICs that have very degraded performance. One such example was a Samsung netbook that had been upgraded to Windows 8 and was using the BCMWL63.SYS driver dated 13/03/2012 version 5.100.245.20; downgrading the driver to the Windows 7 version (BCMWL664.SYS version 5.100.82.95) greatly improved performance. The downlevel driver was obtained from the Samsung support page for the netbook.

Advertisements

Written by adamsync

September 5, 2012 at 23:28

2 Responses

Subscribe to comments with RSS.

  1. Do the software trains need to be applied to the routers or the actual computer that is trying to connect to the network? I have an issue connecting to my universities WPA2 AES network now that I have switched to windows 8. Is there anything I can do about it on my end or am I stuck waiting for the IT to catch up the routers? Thanks

    Alessandro

    November 6, 2012 at 00:00

    • The updates are for Cisco Wireless LAN Controllers; so if they are using those they will need to update them. Some Windows 8 machines will be able to connect if they are running a non-Windows 8 driver for their WiFi card. If you could find a Windows 7 driver for your device that would likely work but the best approach would be to raise a support ticket with the University IT service and draw attention to the available information and ask them about their upgrade plans (assuming that they are using Cisco).

      adamsync

      November 6, 2012 at 20:54


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: