Cisco Load Balance configuration

 

 

Cisco Load Balance configuration

More detail explanations can be found a http://www.Cisco.com

 

Sometime referred to as advanced Load Balancing (Load balancing +). Is an enhancement to Aggressive load balancing, it allows you to configure load balancing per WLAN. Feature is disabled by default

 

Feature load balances wireless clients across Access point. Clients are only able to be load balanced across access points on the same WLC. Load balancing does not occur between access points on different controllers.

 

Load balancing only works at the association phase.

 

when a client tries to associate to a Cisco Lightweight Access point, association response packet is sent to the client with an 802.11 response packet including status code 17. The code 17 indicates that the AP is busy, so the client has to look for another AP to associate with.

 

The AP responds with association response bearing “success” if the AP threshold is not et, and with code 17(AP busy) I the AP utilization threshold is reached or exceed and another less busy AP heard the client request.

 

Problem can arise, if AP discarded or sends a status code 17 to client then client have to decide to ignore it or still use the same AP. Some client driver uses the same AP for connection once again but most of the other type of clients tries to find other AP for connection. So it depends on vendor drivers, as you cannot force them to accept the status code 17.

 

It is recommend not to enable this feature for the voice WLAN as it can cause roaming issues. For other WLANs, it should be enabled only after testing.

 

• • • Client Window size: the client size window and client n least loaded AP determine the load balance threshold value.

Before configuring the load balance intelligence, remember the formula. An AP is considered busy once it has a number of associated clients equal to the client windows size plus the number of clients on the least loaded AP in the area

Load-balancing threshold= client window size + number of clients on the least loaded AP

 

Example: 3 AP

AP1: 9 clients

AP2: 7 clients

AP3: 4 clients

 

As per last default settings on last screen shoot client window size is 5

As per formula, load balance threshold is =5+4=9

Means if any new client wants to join AP1 then client will get the status 17(busy) message or in other words this AP(AP1) is considered to be busy.

• • • Maximum Denial count: the maximum denial count parameter allows the user to configure the number of times the client associations will be rejected for a particular AP. The maximum denial count can have a value between 0 and 10

 

Network configuration

Form GUI:

Figure 1. Client Load balancing global configuration windows

Figure 2. Client Load balancing configuration per WLAN

Form cli:

Figure 3 Client Load balancing configuration options

Figure 4. Client Load balancing window

 

Figure 5. Client Load balancing denial count

Figure 6. enabling Client Load balancing configuration

Figure 7. Disabling WLAN inference

then enable Client Load balancing by # Config plan load-balance allow 1

Figure 8. enable WLAN inference

Figure 9. Displaying Load balancing information

 

 Figure 10. Displaying WLAN configuration information