Client issues when upgrading to 802.11n

We recently had an issue with an 802.11n upgrade that I would like to share.  Setting the scene – Cisco controllers recently upgraded to 7.0.220.0, HT enabled, with a building full of Cisco Aironet 1130 AG series access points.

A conference area was then refreshed with Cisco 3502i series access points.  Reports started to come in that laptops were locking up when clients roaming to the conference area from other parts of the building where the 1130 series access points are located.  Laptops are company issued HP 6930p series.

Below you will find details on the laptop models, OSes, and driver versions that were tested and their results.  You will also see the different testing scenarios and their results below that.  However, to summarize:

The only laptop that was able to reproduce the lockup issue was a 6930p running Windows XP with a 5300 AGN wireless adapter using 12.0.0.82 driver.  6930p running 12.4.4.5 and 14.3.2.1 drivers worked without an issue. 

After updating  the drivers to 14.3.2.1 (driver install package reads 14.3.1.1 but after installing it reports the driver as 14.3.2.1).  Feedback from those laptop customers it appears to have resolved their lockup issues.

Please don’t stop reading now.  Scroll all the way to the bottom and take a look at the testing scenarios!

Models tested

• 6930p - Intel 5300 AGN - 12.0.0.82 - (XP) (14.3.2.1.)
• Device connected to 3502 AP worked fine for approximately 1.5 hours
• After roaming with laptop, it locked up and had to power cycle to recover
• With AP connected to 3502, shutting down 3502 which would force client to roam to another AP
1. Client wireless adapter locked up, but OS was still functioning  sluggishly.
2. Had to power cycle laptop to recover
• Updated driver to 14.3.2.1 and tested the same scenarios above and client worked in all cases.

• 6930p - Intel 5300 AGN - 12.4.4.5 – (XP)
• No issues, functioned properly
• 8460p - Intel 6205 advanced N - 14.0.2.2 - (Win7)
• No issues, functioned properly
• 8460p - Intel 6205 advanced N - 14.0.1.2 - (XP)
• No issues, functioned properly
• 6910p - Intel 4965 AGN - 12.2.0.11 - (XP)
• No issues, functioned properly
• 6930p - Intel 5300 AGN - 12.4.0.21 - (XP)
• No issues, functioned properly
• 8440p - Intel 6200 advanced AGN - 14.0.1.2 - (XP)
• No issues, functioned properly
• 8460p - Intel 6205 advanced N - 15.1.1.1 - (XP)
• No issues, functioned properly
• 6930p - Intel 5300 AGN - 12.4.1.4 - (Win7)
• No issues, functioned properly
• 6910p - Intel 4965 AG - 13.0.0.107 - (Win7)
• No issues, functioned properly

Testing scenarios

·         Client using 802.11g only

o    Unable to test this as the laptop that had the problem would not honor the adapter settings when disabling 802.11n mode and setting radio to 802.11g only (still connected at 802.11an)

o    This happened with the 12.0.0.82 and 14.3.2.1 drivers

o    Interesting thing is with the 6930p that has 12.4.4.5 drivers, it would properly honor the settings of disabling 802.11n and connecting at 802.11g only

·         Client using 802.11a only

o    Unable to test this as the laptop that had the problem would not honor the adapter settings when disabling 802.11n mode and setting radio to 802.11a only (still connected at 802.11an)

o    This happened with the 12.0.0.82 and 14.3.2.1 drivers

o    Again - interesting thing is with the 6930p that has 12.4.4.5 drivers, it would properly honor the settings of disabling 802.11n and connecting at 802.11a only

·         Client using 802.11an

o    Of all the laptop models and OSes tried, only the 6930p with 12.0.0.82 driver locked up.  All others worked fine.

o    6930p with 12.4.4.5 drivers worked just fine on 802.11an, no issues.

·         Roam between 1130 and 3502

o    The 6930p with 12.0.0.82 drivers locked up when roaming from 3502 to 1130 AP, issue was resolved when upgrading to 14.3.2.1 driver

o    The 6930p with 12.4.4.5 drivers worked just fine when roaming, no issues.

·         disable HT on wireless controller

o    all clients worked fine while connected at 80211a and 802.11g radios.  This, of course, is not the direction you want to go when you just upgraded your network to HT.