MSM7xx Controllers Configuration Guide v6.4.0

can be reduced. Otherwise, it is better to accept the fact that the radios must share the channel,
and to operate the radios at full power.
Radio-down mitigation (system-wide)
When this option is enabled, the controller will attempt to mitigate wireless coverage issues created
by inoperable radios.
Each AP in the network maintains a list of neighboring AP radios, with information gathered from
the beacons it receives. These beacons may be received on the current operating channel and
also by scanning non-operating channels in both the 2.4 GHz or 5 GHz frequency bands. (Channel
scanning is configurable on the Radio page. The AP will track information only for the channels
that are being scanned.)
Each AP monitors the state of its neighbors to detect radio-down transitions. An AP only monitors
nearby neighbors, those whose beacons are received reliably and with a high RSSI (received
signal strength indicator).
When an AP stops receiving beacons from a nearby neighbor for a period of time, it informs the
controller. Subsequently, if the AP starts receiving beacons from that neighbor, it will inform the
controller that the neighbor radio is back.
The controller maintains a list of all neighbors. Based on the radio-down indications it receives,
the controller analyzes the situation to determine if the radio-down (or AP-down) condition is valid.
Basically, the controller waits for indications from several neighboring APs before deciding that
an AP radio has failed. It then sends messages to neighbors of the failed AP to mitigate the problem.
Actions that might be taken include:
• Increase the power of neighbor radios (if any are operating at less than maximum power) to
cover the area that was serviced by the failed radio.
• Accept new client stations with below-normal RSSI so clients that were serviced by the failed
radio can reconnect.
The controller reports the radio-down condition as an alarm. Additional diagnostic information is
also logged.
This feature also detects channel changes by neighboring radios, and generates an event for each
occurrence. In these cases, no mitigation is needed because the radio is still operating.
AP load balancing (system-wide)
(Not supported on the HP 517.)
Use these options to set up RRM to periodically perform an analysis and apply the results to the
network automatically if desired. If the automatic option is not enabled, the administrator will have
to apply the new baseline manually.
The AP load balancing feature provides administrators with a way to spread the wireless load
between radios. The goal of load balancing is to have the wireless client count for each radio
match the average wireless client count across all radios on APs operating nearby.
When this option is enabled, the controller tracks the number of associated wireless clients on each
controlled AP/radio. Using the network map, the controller identifies the neighbors of each radio,
and computes the average number of clients per radio for those neighbors. The averages are
computed separately for each band (2.4 GHz and 5 GHz) and are communicated to each AP
periodically.
Configuring and conducting RRM analysis 191