Cisco Cisco Aironet 1000 Series Lightweight Access Point Prospecto
2. APs periodically send out Neighbor Messages, sharing information about themselves, their controllers,
and their RF Group Name. These neighbor messages can then be authenticated by other APs sharing
the same RF Group Name.
the same RF Group Name.
3. APs that can hear these Neighbor Messages and authenticate them based on the shared RF Group
Name, pass this information (consisting primarily of controller IP address and information on the AP
transmitting the neighbor message) up to the controllers to which they are connected.
transmitting the neighbor message) up to the controllers to which they are connected.
4. The controllers, now understanding which other controllers are to be a part of the RF Group, then form
a logical group to share this RF information and subsequently elect a group leader.
5. Equipped with information detailing the RF environment for every AP in the RF Group, a series of RRM
algorithms aimed at optimizing AP configurations related to the following are run at the RF Group
Leader (with the exception of Coverage Hole Detection and Correction algorithm which is run at the
controller local to the APs):
Leader (with the exception of Coverage Hole Detection and Correction algorithm which is run at the
controller local to the APs):
DCA
TPC
Note:
RRM (and RF Grouping) is a separate function from inter-controller mobility (and Mobility Grouping).
The only similarity is the use of a common ASCII string assigned to both group names during the initial
controller configuration wizard. This is done for a simplified setup process and can be changed later.
controller configuration wizard. This is done for a simplified setup process and can be changed later.
Note:
It is normal for multiple logical RF groups to exist. An AP on a given controller will help join their
controller with another controller only if an AP can hear another AP from another controller. In large
environments and college campuses it is normal for multiple RF groups to exist, spanning small clusters of
buildings but not across the entire domain.
environments and college campuses it is normal for multiple RF groups to exist, spanning small clusters of
buildings but not across the entire domain.
This is a graphical representation of these steps:
Figure 1: Neighbor Messages from APs give WLCs a system-wide RF view to make channel and power
adjustments.
adjustments.
RF Grouping Algorithm
RF Groups are clusters of controllers who not only share the same RF Group Name, but whose APs hear each
other.
other.
Table 1: Functionality Breakdown Reference
Functionality
Performed at/by:
RF Grouping
WLCs elect the Group
Leader
Leader
Dynamic Channel Assignment
Group Leader
Transmit Power Control
Group Leader
Coverage Hole Detection and
Correction
Correction
WLC