Everything Instant On

How Radios are managed on Instant ON APs?

  • 1.  How Radios are managed on Instant ON APs?

    Posted 12-16-2019 07:44 PM

    Aruba Instant ON APs supports Adaptive Radio Management(ARM) which takes care of the Wireless Network Performance.

    What is ARM?

    Adaptive Radio Management (ARM) is a Radio Frequency Management Technology that optimizes WLAN performance even in the networks with highest traffic

    • ARM takes care of Power management and interference by dynamically and intelligently choosing the best 802.11 channel and transmitting power for each AP in its current RF environment.
    • Deployments with dozens of users per access point can cause network contention and interference, but ARM dynamically monitors and adjusts the network to ensure that all users are allowed ready access. 
    • ARM dynamically scans all 802.11 channels within its 802.11 regulatory domain at specific interval and generate reports on each AP. This report will be shared to all the APs in the Network and based on the report, Interference and Power will be managed.  
    • Automatic power control in ARM adjusts AP power settings automatically if adjacent APs are added, removed or moved to a new location within the network, which minimizes interference with other WLAN networks. ARM adjusts only the affected APs, so the entire network does not require systemic changes.
    • ARM works with all standard clients, across all operating systems, while remaining in compliance with the IEEE 802.11 standards. It does not require any proprietary client software to achieve its performance goals. 

    How does ARM work?

    By default below features are supported by ARM on Aruba Instant ON AP.

    Band Steering

    Band Steering is one of the features of ARM. As there are more resources available on 5Ghz, Band steering has been designed to encourage dual-band capable clients connect to 5Ghz than 2.4Ghz on dual-band APs. By moving dual-band capable clients to 5Ghz, more resources can be availed on the 2.4GHz band for single-band clients.

    The band steering feature considers several metrics before it determines if a client should be steered to the 5GHz band, including client RSSI. For example, this feature will only steer a client to the 5GHz band if that client detects an acceptable RSSI value from an 5GHz AP radio, and the signal from the 5Ghz radio is not significantly weaker than the RSSI from the 2.4GHz radio.

    This feature also takes into account the current load on each radio of a AP. The band steering feature will NOT steer more clients to 5GHz on that AP if there are many clients associated to the AP, and significantly more 802.11a clients than 80211g clients.

    The band steering feature will not proactively disconnect clients that are already associated with a radio. All band steering occurs when a client is trying to associate to a new AP radio.

    By default, Prefer-5GHz is enabled on Instant ON AP.

    In prefer-5GHz band steering mode, the AP will not respond to 2.4 Ghz probe requests from a client if all the following conditions are met.

    • The client has already probed the AP on the 5Ghz band and therefore is known to be capable of sending probes on the 5Ghz band.
    • The client is not currently associated on the 2.4Ghz radio to this AP.
    • The client has sent less than 8 probes requests/auth in the last 10 seconds. If the client has sent more than 8 probes in the last 10 seconds, the client will be able to connect using whatever band it prefers

    Airtime Fairness

    Airtime Fairness is needed to provide every client with an equal opportunity to utilize the network bandwidth irrespective of client type, capability or operating system.

    By default, ARM on Aruba Instant ON AP has the air time fairness mode set to default-access  which ensures the fair distribution of available Wi-Fi bandwidth to all clients.

    Wide Channel Bands

    40 MHz channels can be used by configuring Wide Channels in the 2.4 GHz and 5.0 GHz bands. 40 MHz channels are two 20 MHz adjacent channels that are bonded together. They effectively doubles the frequency bandwidth available for data transmission. For high performance, 5.0 GHz band can be configured for Wide band. If the AP density is low, 2.4GHz band can be configured.

    By default, ARM on Aruba Instant ON AP has the Wide Band set to 5GHz.