ARM Coverage and Interference Metrics

ARM Adaptive Radio Management. ARM dynamically monitors and adjusts the network to ensure that all users are allowed ready access. It enables full utilization of the available spectrum to support maximum number of users by intelligently choosing the best RF channel and transmit power for APs in their current RF environment. computes coverage and interference metrics for each valid channel, and chooses the best performing channel and transmit power settings for each AP’s RF Radio Frequency. RF refers to the electromagnetic wave frequencies within a range of 3 kHz to 300 GHz, including the frequencies used for communications or Radar signals. environment. Each AP gathers other metrics on their ARM Adaptive Radio Management. ARM dynamically monitors and adjusts the network to ensure that all users are allowed ready access. It enables full utilization of the available spectrum to support maximum number of users by intelligently choosing the best RF channel and transmit power for APs in their current RF environment. -assigned channel to provide a snapshot of the current RF Radio Frequency. RF refers to the electromagnetic wave frequencies within a range of 3 kHz to 300 GHz, including the frequencies used for communications or Radar signals. health state.

The information described below appears in the output of the show ap arm rf-summary command.

The following two metrics help the AP decide which channel and transmit power setting is best:

Coverage Index: The AP uses this metric to measure RF Radio Frequency. RF refers to the electromagnetic wave frequencies within a range of 3 kHz to 300 GHz, including the frequencies used for communications or Radar signals. coverage. The coverage index is calculated as x/y, where “x” is the AP’s weighted calculation of the SNR Signal-to-Noise Ratio. SNR is used for comparing the level of a desired signal with the level of background noise. on all valid APs on a specified 802.11 802.11 is an evolving family of specifications for wireless LANs developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). 802.11 standards use the Ethernet protocol and Carrier Sense Multiple Access with collision avoidance (CSMA/CA) for path sharing. channel, and “y” is the weighted calculation of the AP SNR Signal-to-Noise Ratio. SNR is used for comparing the level of a desired signal with the level of background noise. the neighboring APs see on that channel.

To view these values for an AP in your current WLAN Wireless Local Area Network. WLAN is a 802.11 standards-based LAN that the users access through a wireless connection. environment, issue the show ap arm rf-summary ap-name <ap-name> CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. command, where <ap-name> is the name of an AP for which you want to view information.

Interference Index: The AP uses this metric to measure co-channel and adjacent channel interference. This metric is calculated and weighted for all APs, including third-party APs seen on a specified 802.11 802.11 is an evolving family of specifications for wireless LANs developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). 802.11 standards use the Ethernet protocol and Carrier Sense Multiple Access with collision avoidance (CSMA/CA) for path sharing. channel and its adjacent channels. An adjacent channel is 25 MHz Megahertz of the primary 20 MHz Megahertz channel. For example, channel 40 is adjacent, because it is 20 MHz Megahertz away from channel 36. The Interference Index is calculated as a/b/c/d, where:

Metric value “a” is the channel interference the AP sees on its selected channel.

Metric value “b” is the interference the AP sees on the adjacent channel.

Metric value “c” is the channel interference the AP’s neighbors see on the selected channel.

Metric value “d” is the interference the AP’s neighbors see on the adjacent channel.

To manually calculate the total Interference Index for a channel, issue the show ap arm rf-summary ap-name <ap-name> CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. command, then add the values a+b+c+d.

The following CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. example describes the interference index calculation involving four metric values:

(host) [md] (config) # show ap arm rf-summary ap-name ap1

Channel Summary

---------------

channel retry phy-err mac-err noise util(Qual) cov-idx(Total) intf_idx(Total)

------- ----- ------- ------- ----- ---------- -------------- ---------------

149 0 0 0 96 8/7/0/0/99 8/0(8) 18/11//4/1(34)

153 0 0 0 92 6/3/2/0/99 3/0(3) 32/22//3/0(57)

157 0 0 0 92 3/0/2/0/99 7/0(7) 50/13//2/5(70)

161 0 0 0 92 3/0/2/0/95 0/1(1) 7/17//5/0(29)

For channel 149, the interference index values are 18/11//4/1 where:

a= 18 (due to neighbors on channel 149)

b = 11 (due to neighbors on channel 153)

c = 4 (due to two-hop neighbors on channel 149)

d = 1 (due to two-hop neighbors on channel 153)

Hence, the interference index total on channel 149 is a+b+c+d i.e., 18+11+4+1 = 34.

Each AP also gathers the following additional metrics, which can provide a snapshot of the current RF Radio Frequency. RF refers to the electromagnetic wave frequencies within a range of 3 kHz to 300 GHz, including the frequencies used for communications or Radar signals. health state. View these values for each AP using the show ap arm rf-summary ip-addr <ap ip address> or show ap arm rf-summary ap-name <ap-name> CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. command.

Amount of Retry frames (measured in %)

Amount of Bandwidth seen on the channel (measured in kbps)

Amount of PHY errors seen on the channel (measured in %)

Amount of MAC Media Access Control. A MAC address is a unique identifier assigned to network interfaces for communications on a network. errors seen on the channel (measured in %)

Noise floor value for the specified AP

The following enhancements are introduced in ArubaOS 8.0.0.0 to resolve issues that occur with the distributed channel/power algorithm:

Push random channel assignments to APs: To support the random channel assignment feature, set the Assignment parameter in the ARM Adaptive Radio Management. ARM dynamically monitors and adjusts the network to ensure that all users are allowed ready access. It enables full utilization of the available spectrum to support maximum number of users by intelligently choosing the best RF channel and transmit power for APs in their current RF environment. profile to maintain. Once this is done, random channels are pushed from the managed device STM Station Management. STM is a process that handles AP management and user association./SAPM to APs that belong to a specific ap-group. This helps in replacing the dynamic channel change solution in a high density environment, thereby overcoming the issue with convergence. Random channel assignment helps in certain customer deployments where administrators want to control channels assigned and also for initial channel assignment to seed ARM Adaptive Radio Management. ARM dynamically monitors and adjusts the network to ensure that all users are allowed ready access. It enables full utilization of the available spectrum to support maximum number of users by intelligently choosing the best RF channel and transmit power for APs in their current RF environment. channel computation.

Reduce interference channel change: To reduce the number of interference channel changes and to configure the weight of interfering APs when calculating the interference index, the interfering-ap-weight parameter is introduced in the rf-arm-profile command. Before this enhancement was introduced, the value of the interfering AP (uncontrollable AP) was similar to the valid AP (controllable AP).