Specifications

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Cisco Wireless LAN Controller Configuration Guide
OL-21524-02
Chapter 4 Configuring Controller Settings
Configuring Aggressive Load Balancing
When a wireless client attempts to associate to a lightweight access point, association response packets
are sent to the client with an 802.11 response packet including status code 17. This code indicates
whether the access point can accept any more associations. If the access point is too busy, the client
attempts to associate to a different access point in the area. The system determines if an access point is
relatively more busy than its neighbor access points that are also accessible to the client.
For example, if the number of clients on AP1 is more than the number of clients on AP2 plus the
load-balancing window, then AP1 is considered to be busier than AP2. When a client attempts to
associate to AP1, it receives an 802.11 response packet with status code 17, indicating that the access
point is busy, and the client attempts to associate to a different access point.
You can configure the controller to deny client associations up to 10 times (if a client attempted to
associate 11 times, it would be allowed to associate on the 11th try). You can also enable or disable load
balancing on a particular WLAN, which is useful if you want to disable load balancing for a select group
of clients (such as time-sensitive voice clients).
Note Cisco Aironet 600 Series OfficeExtend and Hybrid-REAP access points do not support client load
balancing.
Client Association Limits
The maximum number of client associations that the access points can support is dependent upon the
following factors:
• The maximum number of client associations differs for lightweight and autonomous Cisco IOS
access points.
• There may be a limit per radio and an overall limit per AP.
• AP hardware (the 16-MB APs have a lower limit than the 32-MB and higher APs).
Client Association Limits for Lightweight Access Points
The Per-AP limits are as follows:
• For 16-MB APs, the limit is 128 clients per AP. This limit is applicable to 1100 and 1200 series APs.
• For 32-MB and higher APs, there is no per-AP limit.
The per-radio limits are as follows:
• For all Cisco IOS APs, the limit is 200 associations per radio.
• For all 1000 and 1500 series APs, which are not supported beyond release 4.2, the limit is 250
associations per radio.
With 32-MB and higher lightweight Cisco IOS APs, with two radios, up to 200 + 200 = 400 associations
are supported.
Client Association Limits for Autonomous Cisco IOS Access Points
The client association limits for autonomous Cisco IOS access points are as follows:
The limit is around 80 to 127 clients per AP. This number varies depending on the following factors:
• AP model (whether it is 16 MB or 32 MB or higher).
• Cisco IOS version.