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Wireless Controller Redundancy with No Client Reauthentication Needed

July 12, 2013 at 5:00 am PST

Last fall, I blogged about No SSID Outage or Access Point Stateful Switchover introduced with the AireOS 7.3 release whereby if your wireless LAN Controller fails due to some hardware failure, thousands of Access Points fail over sub-second to the standby controller! This is possible due to continuous synchronization of CAPWAP states, Configuration Changes, Radio Channel and Power, Roaming Keys and Access Point licenses between the two Controllers. This means even if the administrator changes the configuration, channel plans or the clients roam and the primary controller fails; the Access Points will simply fail over in a stateful fashion to the secondary. In this blog, I will share details on the upcoming enhancements to High Availabilty with the 7.5 release.

In the upcoming AireOS 7.5 release, we take High Availability to the next level with two critical enhancements.

1. Today, after Access Points fail over from the primary to the standby controller, each client tries to re-authenticate and the standby controller then checks against its CCKM database whether the client has already authenticated. At the rate of several tens of authentications per second, it can take anywhere from zero to a few hundred seconds for the tens of thousands of clients that are connected to a controller to re-authenticate. The client stateful essentially eliminates this downtime with sub-second failover. Thus the total downtime that any user running a voice-call or Citrix session experiences is 2-3 seconds that the application requires to reconnect.

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Get your Wi-Fi network ready for Windows 8

October 12, 2012 at 5:00 am PST

Microsoft will launch Windows 8 in late October. Along with a slew of other features, it will be among the first to support the 802.11w standard to protect Management Frames for client devices on Wi-Fi networks.

Customers running old Cisco unified releases (between 4.2 to 7.2) in local, Flex or mesh mode will run into an interoperability bug (CSCua29504, to be exact) that prevents 802.11w enabled clients from connecting to a Cisco WLAN with Management Frame Protection (MFP) enabled. This bug does not affect customers running autonomous access point deployments or customers running Cisco unified releases older than 4.2.

What are the possible solutions for you?

1. Please upgrade your production environment to one of the following releases, which will interoperate with Windows 8.

  • 7.3.101.0
  • 7.2.111.3
  • 7.0.235.3

2. Roll back to pre-windows 8 drivers as identified in the Microsoft Knowledge Base article.
3. Fall back to TKIP
4. Sign up for a beta release for Cisco’s upcoming feature release 7.4 (beta available now!) that supports the 802.11w feature in local mode.

What is 802.11w ?

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Always-On Mobile Experience with Wi-Fi

August 16, 2012 at 12:53 pm PST

Importance of High Availability:  If you are reading this blog, you likely own 2-5 Wi-Fi-capable devices: laptops, mobile phones, or tablets. From employees to students, from doctors to guests, the common theme is that everyone now uses wireless as a preferred mode of access.

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