Users Guide

Dell PowerConnect ArubaOS 5.0 | User Guide Adaptive Radio Management (ARM) | 147
Multi-Band ARM and 802.11a/802.11g Traffic
Dell recommends using the multi-band ARM assignment and Mode Aware ARM feature for single-radio APs in
networks with traffic in the 802.11a and 802.11g bands. This feature allows a single-radio AP to dynamically
change its radio bands based on current coverage on the configured band. This feature is enabled via the AP's
ARM profile.
When you first provision a single-radio AP, it initially operates in the radio band specified in its AP system profile.
If the AP finds adequate coverage on multiple channels in its current band of operation, the mode-aware feature
allows the AP to temporarily turn itself off and become an AP Air Monitor (APM). In AP Monitor mode, the AP
scans all channels across both bands to verify that each channel meets or exceeds its required level of acceptable
radio coverage (as defined by the in the ARM profile).
If the AP Monitor detects that a channel on the 802.11g band does not have adequate radio coverage, it will
convert back to an AP on that 802.11 channel. If the 802.11g band is adequately covered, the AP Monitor will
next check the 802.11a band. If a channel on the 802.11a band lacks coverage, the AP Monitor will convert back
to an AP on that 802.11a channel.
Band Steering
ARM’s band steering feature encourages dual-band capable clients to stay on the 5GHz band on dual-band APs.
This frees up resources on the 2.4GHz band for single band clients like VoIP phones.
Band steering reduces co-channel interference and increases available bandwidth for dual-band clients, because
there are more channels on the 5GHz band than on the 2.4GHz band. Dual-band 802.11n-capable clients may
see even greater bandwidth improvements, because the band steering feature will automatically select between
40MHz or 20MHz channels in 802.11n networks. This feature is disabled by default, and must be enabled in a
Virtual AP profile.
The band steering feature supports both campus APs and remote APs that have a virtual AP profile set to tunnel,
split-tunnel or bridge forwarding mode. Note, however, that if a campus or remote AP has virtual AP profiles
configured in bridge or split-tunnel forwarding mode but no virtual AP in tunnel mode, those APs will gather
information about 5G-capable clients independently and will not exchange this information with other APs that
also have bridge or split-tunnel virtual APs only.
Enabling Band Steering via the WebUI
Band steering is configured in a virtual AP profile. Use the following procedure to enable or disable Band Steering
using the WebUI:
1. Select Configuration > All Profiles. The All Profile Management window opens.
2. Select Wireless LAN to expand the Wireless LAN section.
3. Select Virtual AP profile to expand the Virtual AP Profile section.
4. Select the name of the Virtual AP profile for which you want to enable band steering.
(To create a new virtual AP profile, enter a name for a new profile in the Profile Details window, then click
Add button. The new profile will appear in the Profiles list. Select that profile to open the Profile Details
pane.)
5. In the Profile Details pane, select Band Steering. to enable this feature, or uncheck the Band Steering
checkbox to disable this feature.
Note: The Band Steering feature may not work correctly unless you use the enable the "Local Probe Response" parameter in the
Wireless LAN SSID profile for the SSID that requires band steering. You can enable the local probe response parameter using the
CLI command wlan ssid-profile <profile> local-probe-response, or via the WebUI by navigating to Configuration>All Profiles,
expanding the Wireless LAN and SSID Profile menus, then selecting the SSID profile and checking the Local Probe Response
checkbox in the SSID Profile Details window.