AirMatch RF Management Overview


ArubaOS 8.x does not support AirMatch in master controller mode.

The AirMatch channel and EIRP optimization features deprecate the channel planning and EIRP optimization features in the legacy Adaptive Radio Management (ARM) feature. AirMatch is supported on Mobility Master only, while legacy ARM channel optimization and EIRP features continue to be supported by stand-alone controllers running ArubaOS 8.0.

AirMatch channel planning evens out channel distributions in any size of network, and in any subset of the contiguous network (as much as allowed by the network configuration, regulatory domain, and AP hardware capability). AirMatch also minimizes channel coupling, where adjacent radios are assigned to the same channel. The computing power of Mobility Master impacts channel distribution calculations, so channel coupling may occasionally be allowed in complex networks to keep the computing time practical.

AirMatch EIRP planning automatically considers the local density of the network to manage the APs' coverage and modulation and coding scheme (MCS) operation, and optimizes EIRP changes across neighboring AP radios in order to offer users the best roaming experience.

Table 1 describes some of the differences between the channel and EIRP optimization features supported by ArubaOS AirMatch and ArubaOS ARM.

Table 1: AirMatch and ARM in ArubaOS




Initial Release

ArubaOS 8.0

ArubaOS 2.x

Supported Topology

Mobility Master / Managed device

Stand-alone controller

Run Period

24 hours

As little as 5 minutes

RF information used

Past 24 hours of RF data

Instantaneous snapshot of the RF environment

Deployment Time

5 AM (by default) , or any time necessary

Any time necessary

Computing Time

Depends upon network size

Less than 1 second

Optimization Scope

The entire RF network

Each individual AP

AirMatch Channel Assignments

Each AP in a Mobility Master deployment measures its RF environment for a five minute period, every 30 minutes by default. The AP then sends AMON messages about the radio feasibility to the managed device based on that AP's hardware capability, radio and regulatory domain, and RF neighbors. The managed device forwards these messages to the Mobility Master. The Mobility Master adds this information to a database, computes an optimal solution, and deploys the latest RF plan by sending updated settings to the APs. By default, this configuration update is sent at 5 AM (as per the Mobility Master system clock), but time of this configuration update can be modified via the AirMatch profile.


An exception to this daily update is an automatic channel change due to a radar detection event or high noise interference. If an AP detects a radar event on its current operating channel, that AP automatically changes to another supported channel to avoid radar interference, and does not wait for the daily RF configuration update from the Mobility Master. An AP may also automatically change channels if a very high noise level is detected on the current channel, if at least one other channel is free of noise.

In ArubaOS 8.0, AirMatch moves a radio to a random channel when a radar event is detected, or if a high noise floor is detected on a non-static channel. Starting with ArubaOS 8.0.1, AirMatch uses the criteria described in Table 2 to assign a new channel.

Table 2: Channel Assignment Logic

Issue Prompting Channel Change

Channel Selection Criteria

Detected radar

AirMatch selects a channel with a minimum interference index from the channels without high noise or a radar condition.

High channel noise

The channel selection criteria varies between static and non-static channels.

If static channel is configured, the channel does not change due to a high noise condition.
For a non-static channel, AirMatch selects a channel with a minimum interference index from the channels without high noise or a radar condition.

Channel Quality Improvement Thresholds

ArubaOS 8.0.1 introduces the AirMatch channel quality improvement threshold, which allows you to select the minimum channel improvement that can trigger a new scheduled channel solution. The default threshold value is a 15% improvement. If a proposed channel change will not produce an improvement that meets or exceeds this threshold, AirMatch will not trigger a channel change.


This channel quality setting only applies to scheduled updates. If you manually trigger an update using the airmatch runnow command, AirMatch will deploy the new solution regardless of the level of improvement.

Initial RF Calculations

The database for the AirMatch service is empty when Mobility Master first boots up. When Mobility Master first detects APs on the network, it enters its initial optimization phase, collects data from all the APs, and generates an incremental solution every 30 minutes (by default) for the next eight hours. When this initial eight-hour period has elapsed, the AirMatch service will periodically calculate a new RF configuration for these devices.

When a new AP is deployed on a network with an active Mobility Master during the initial 8-hour AirMatch optimization phase, that AP joins the network with its preassigned channel and transmission power values. The AirMatch service detects the newly deployed AP on the network, restarts its RF computations, and sends an incremental RF configuration update to the new AP 30 minutes later. APs added to the network after the initial 8-hour optimization period will not receive an additional RF configuration update until the next scheduled update period.

For more information on AirMatch configuration and management, see Configuring AirMatch