Cisco Flexible Radio Assignment

Flexible radio assignments

A Flexible Radio Assignment (FRA) is a configuration management feature that

  • adapts AP radio hardware for multiple roles

  • manages various Cisco AP models like Cisco Aironet 2800 Series Access Points, Cisco Aironet 3800 Series Access Points, and other APs in Catalyst series, and

  • optimizes client experience by adapting radio roles based on client capabilities

FRA takes advantage of the dual-band radios included in APs. The FRA is a new feature added to the RRM to analyze the Neighbor Discovery Protocol (NDP) measurements, which manages the hardware used to determine the role of the new flexible radio (2.4 GHz, 5 GHz, or monitor) in your network.

Traditional legacy dual–band APs always had 2 radio slots, (1 slot per band) and were organized by the band they were serving, that is slot 0= 802.11b,g,n and slot 1=802.11a,n,ac.

Benefits of the FRA

  • Solves the problem of 2.4–GHz over coverage.

  • Creates two distinct 5–GHz cells to double available airtime.

  • Permits one AP with one Ethernet drop to function like two 5–GHz APs.

  • Introduces the concept of macro and micro cells for airtime efficiency.

  • Allows more bandwidth to be applied to an area within a larger coverage cell.

  • Addresses nonlinear traffic distribution.

  • Enhances the High-Density Experience (HDX) with one AP.

  • Allows XOR radios to serve client or monitor roles based on configuration.

XOR support in 2.4-GHz or 5-GHz bands

XOR support increases flexibility in AP operations by offering capabilities to serve various frequency bands and monitor radio signals, thereby optimizing network coverage and efficiency.

The flexible radio (XOR) offers the ability to serve the 2.4-GHz or the 5-GHz bands, or passively monitor both bands on the same AP.

  • AP models supporting dual 5-GHz band operations:

    • i model supports a dedicated Macro/Micro architecture.

    • e and p models support Macro/Macro architecture.

  • FRA with internal antenna (i series models) allows two 5-GHz radios in Micro/Macro cell mode.

  • FRA with external antenna (e and p models) enables creation of two separate macro or micro cells for HDX.

  • FRA calculates redundancy for 2.4-GHz radios with a metric called COF (Coverage Overlap Factor).

  • Feature integration in RRM for mixed environments and AP AP MODE selections include:

    • Local Mode

    • Monitor Mode

    • FlexConnect Mode

    • Sniffer Mode

    • Spectrum Connect Mode

Before XOR was introduced, mode changes affected the entire AP (both radio slot 0 and slot 1). The XOR addition allows operation of a single radio interface independently, known as roles:

  • Client Serving

  • Either 2.4 GHz(1) or 5 GHz(2)

  • Monitor-Monitor mode (3)


Note

  • Mode: Assigned to a whole AP (slot 0 and slot 1)

  • Role: Assigned to a single radio interface (slot 0)

Configure FRA Radio (CLI)

Procedure

Step 1

Enable privileged EXEC mode

Example:

Device# enable

Enters privileged EXEC mode.

Step 2

Enter configuration mode

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

Enable or disable FRA

Example:

Device(config)# [no] ap fra

Enables or disables FRA on the AP.

Step 4

Configure FRA interval

Example:

Device(config)# ap fra interval 3

Configures the FRA interval in hours. The range is 1 to 24 hours.

Note

 
The FRA interval has to be more than the configured RRM interval.

Step 5

Configure the FRA sensitivity

Example:

Device(config)# ap fra sensitivity high

Configures the FRA sensitivity.

  • high : Sets the FRA Coverage Overlap Sensitivity to high.

  • medium : Sets the FRA Coverage Overlap Sensitivity to medium.

  • low : Sets the FRA Coverage Overlap Sensitivity to low.

Step 6

Exit global configuration mode

Example:

Device(config)# end

Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode.

Step 7

Reverts to XOR radio state

Example:

Device# ap fra revert all auto

Rolls back the XOR Radio state.

  • all : Reverts all XOR Radios

  • auto-only : Revert only XOR radios currently in automatic band selection.

  • auto : Sets the XOR radios in automatic band selection.

  • static : Sets the XOR radio in static 2.4-GHz band.

Step 8

View the configuration and statistics of 802.11 APs

Device# show ap dot11 5ghz summary

Shows the configuration and statistics of 802.11 Cisco APs

Step 9

View the current FRA configuration

Example:

Device# show ap fra

FRA State                                             : Disabled
FRA Sensitivity                                       : medium (95%)
FRA Interval                                          : 1 Hour(s)

AP Name              MAC Address       Slot ID  Current-Band      COF %      Suggested Mode
-------------------------------------------------------------------------------------------
AP00A6.CA36.295A     006b.f09c.8290    0        2.4GHz            None       2.4GHz     

COF : Coverage Overlap Factor

test_machine#

Shows the current FRA configuration.

Step 10

View the current 802.11 dual-band parameters

Example:

Device# show ap name config dot11 dual-band

Shows the current 802.11 dual-band parameters in a given AP.

Configure FRA radio (GUI)

The purpose of configuring the FRA radio is to optimize the radio assignment for overlapping coverage areas, improving network efficiency and performance. This includes enabling the Flexible Radio Assignment (FRA) status, setting intervals, and adjusting sensitivity levels to ensure optimal coverage.

Procedure

Step 1

Choose Configuration > Radio Configurations > RRM > FRA.

Step 2

In the Flexible Radio Assignment window, enable FRA status and determine the overlapping 2.4 GHz or 5 GHz coverage for each AP, choose Enabled in the FRA Status field. By default, the FRA status is disabled.

Step 3

Under the From the FRA Interval drop-down list, choose the FRA run interval. The interval values range from 1 hour to 24 hours. Choose the FRA run interval value only after you enable the FRA status.

Step 4

From the FRA Sensitivity drop-down list, choose the percentage of Coverage Overlap Factor (COF) required to consider a radio as redundant. You can select the supported value only after you enable the FRA status.

The supported values are as follows:

  • Low: 100 percent

  • Medium (default): 95 percent

  • High: 90 percent

The Last Run and Last Run Time fields will show the time FRA was run last and the time it was run.

Step 5

Check the Client Aware check box to take decisions on redundancy.

When enabled, the Client Aware feature monitors the dedicated 5-GHz radio and when the client load passes a pre-set threshold, automatically changes the Flexible Radio assignment from a monitor role into a 5-GHz role, effectively doubling the capacity of the cell on demand. Once the capacity crisis is over and Wi-Fi load returns to normal, the radios resume their previous roles.

Step 6

In the Client Select field, enter a value for client selection. The valid values range between 0 and 100 percent. The default value is 50 percent.

This means that if the dedicated 5-GHz interface reaches 50% channel utilization, this will trigger the monitor role dual-band interface to transition to a 5-GHz client-serving role.

Step 7

In the Client Reset field, enter a reset value for the client. The valid values range between 0 and 100 percent. The default value is 5 percent.

Once the AP is operating as a dual 5-GHz AP, this setting indicates the reduction in the combined radios' overall channel utilization required to reset the dual-band radio to monitor role.

Step 8

Click Apply to save the configuration.

After completing the configuration, the FRA system will be active, improving the radio coverage efficiency by managing overlapping frequencies and enhancing redundancy decisions. This results in better utilization of network resources and coverage optimization.