Cisco Cisco 2000 Series Wireless LAN Controller
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Release Notes for Cisco wireless LAN controller and Cisco Aironet Lightweight Access Point for Software Release 3.1.59.24
Important Notes
Important Notes
This section describes important information about the wireless LAN controllers and Cisco Aironet
lightweight access points.
lightweight access points.
Important Regulatory Notice
The wireless LAN controller must be installed by a network administrator or qualified IT professional
and the proper country code selected. Following installation, access to the wireless LAN controller
should be password protected by the installer to maintain compliance with regulatory requirements and
ensure proper unit functionality.
and the proper country code selected. Following installation, access to the wireless LAN controller
should be password protected by the installer to maintain compliance with regulatory requirements and
ensure proper unit functionality.
Voice Wireless LAN Configuration
Cisco recommends that Load Balancing ALWAYS be turned off in any wireless LAN that is supporting
voice, regardless of vendor. When Load Balancing is turned on, voice clients can hear an audible artifact
when roaming and the handset is refused at its first reassociation attempt.
voice, regardless of vendor. When Load Balancing is turned on, voice clients can hear an audible artifact
when roaming and the handset is refused at its first reassociation attempt.
Cisco 7920 Wireless IP Phone Support
When using Cisco 7920 Wireless IP phones with wireless LAN controllers, make sure that the phones
and wireless LAN controllers are configured as follows:
and wireless LAN controllers are configured as follows:
•
Aggressive Load Balancing on the wireless LAN controllers must be disabled on a per-wireless
LAN controller basis. Otherwise, the initial roam attempt by the phone may fail, causing a
disruption in the audio path.
LAN controller basis. Otherwise, the initial roam attempt by the phone may fail, causing a
disruption in the audio path.
•
The QoS Basis Service Set (QBSS) information element (IE) must be enabled. The QBSS IE enables
the Cisco Aironet lightweight access point to communicate its channel usage to wireless devices.
Because Cisco Aironet lightweight access points with high channel usage might not be able to
handle real-time traffic effectively, the 7920 phone uses the QBSS value to determine if they should
associate with anotherCisco Aironet lightweight access point. Use the following instructions to
enable the QBSS IE:
the Cisco Aironet lightweight access point to communicate its channel usage to wireless devices.
Because Cisco Aironet lightweight access points with high channel usage might not be able to
handle real-time traffic effectively, the 7920 phone uses the QBSS value to determine if they should
associate with anotherCisco Aironet lightweight access point. Use the following instructions to
enable the QBSS IE:
–
>sh wlan summary
(use this to determine the wireless LAN ID No. of the wireless LAN to which you want to add
QBSS support)
(use this to determine the wireless LAN ID No. of the wireless LAN to which you want to add
QBSS support)
–
>config wlan disable [Wireless LAN ID No.]
–
>config wlan dot11-phone compat [Wireless LAN ID No.]
–
>config wlan enable [Wireless LAN ID No.]
–
>sh wlan [Wireless LAN ID No.]
(use this command to verify that the wireless LAN is enabled and the field marked
“Dot11-Phone Mode (7920)” is in the ‘compat’ mode)
(use this command to verify that the wireless LAN is enabled and the field marked
“Dot11-Phone Mode (7920)” is in the ‘compat’ mode)
–
>save config
•
The Dynamic Transmit Power Control (DTPC) information element (IE) must be enabled. The
DTPC information element is a beacon and probe information element that allows the Cisco Aironet
lightweight access point to broadcast information on its transmit power. The Cisco Wireless IP
DTPC information element is a beacon and probe information element that allows the Cisco Aironet
lightweight access point to broadcast information on its transmit power. The Cisco Wireless IP