Cisco Systems 3.2 Configuring an RF Group

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Cisco Wireless LAN Controller Configuration Guide
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Chapter 9 Configuring Radio Resource Management
Configuring an RF Group
The RF group leader analyzes real-time radio data collected by the system and calculates the master
power and channel plan. The RRM algorithms try to optimize around a signal strength of –65 dBm
between all access points and to avoid 802.11 co-channel interference and contention as well as
non-802.11 interference. The RRM algorithms employ dampening calculations to minimize
system-wide dynamic changes. The end result is dynamically calculated optimal power and channel
planning that is responsive to an always changing RF environment.
The RRM algorithms run at a specified updated interval, which is 600 seconds by default. Between
update intervals, the RF group leader sends keep-alive messages to each of the RF group members and
collects real-time RF data.
Note Several monitoring intervals are also available. See Table 9-1 for details.
RF Group Name
A controller is configured with an RF group name, which is sent to all access points joined to the
controller and used by the access points as the shared secret for generating the hashed MIC in the
neighbor messages. To create an RF group, you simply configure all of the controllers to be included in
the group with the same RF group name. You can include up to 20 controllers and 1000 access points in
an RF group.
If there is any possibility that an access point joined to a controller may hear RF transmissions from an
access point on a different controller, the controllers should be configured with the same RF group name.
If RF transmissions between access points can be heard, then system-wide RRM is recommended to
avoid 802.11 interference and contention as much as possible.
Configuring an RF Group
This section provides instructions for configuring RF groups through either the GUI or the CLI.
Note The RF group name is generally set at deployment time through the Startup Wizard. However, you can
change it as necessary.
Note You can also configure RF groups using the Cisco Wireless Control System (WCS). Refer to the Cisco
Wireless Control System Configuration Guide for instructions.