flexible radio assignment configuration

Learning and Blogging about WIFI

Cisco’s Flexible Radio Assignment (FRA)

I have heard about Cisco FRA for a while but I am only starting to see this out in the field. This technology offers great advancements over statically assigned Radios.

There are two modes of operation in FRA Macro/Macro cell and Macro/Micro cell. I will only be discussing the Macro/Micro mode in this blog. The Macro/Micro cell will have a large cell and a smaller cell inside which will increase capacity on your 5 GHz network.

The theory behind FRA is if you design a network for 5 GHz then you will more than likely have too much 2.4 GHz coverage. This is why FRA is only run against the 2.4 GHz radios.

There are only two AP models that work with FRA. They are the 2800/3800. When the AP creates a Micro cell, the power will always be set to the minimum power of the AP. In the case of the 3802, this would be 2 dBm.

How it Works

FRA uses the Neighbor Discovery Protocol (NDP) from RRM to figure out if there is too much coverage on the 2.4 GHz band. The output of this calculation is called Coverage Overlap Factor (COF). You can set the threshold for the COF at Low 100%, Medium 95% and High 90%. When FRA sees too much coverage based on these thresholds values, it will mark the radio as redundant. Once it is marked redundant it can be assigned another role. There are three states (roles) these radios can be in 2.4GHz/5GHz/Monitor Mode. Depending on the COF the controller will either leave it at 2.4GHz, change it to 5 GHz or put it in Monitor Mode. When the controller puts an AP in Monitor mode the only way to fix this is to reset the AP.

Probe Suppression

The AP can suppress Probe responses from one of the radios. When the APs receives Probe requests on both the Macro and Micro cells within a short period of time from a client who is not associated, the AP can suppress the Probe Responses on the radio which it doesn’t want the device to join. When a client is associated to either radio on the AP, the AP will suppress the Probe Response from the other radio. This should help prevent the client from roaming between radios. The Probe Suppression option is disabled by default on the controller.

FRA will monitor the cells and keep devices that are similar on the same radio. This will help improve throughput. FRA will use 802.11v, 802.k and Probe Suppression to keep the same type of clients on the same radio.

Pros and Cons of FRA

• FRA will give you more capacity in the 5 GHz band.
• FRA eliminates of fixes the balance between 5 GHz and 2.4 GHz radios on your wireless network.
• The controller will limit how many devices can be on the Micro cell.
• If your device authenticates to the Micro Cell and moves away from the Micro cell area. This could force it to roam to the Macro cell, which would increase roaming. These additional roaming events force the device to stay awake more which will affect battery life. Cisco has safeguards against this but just like RRM, it doesn’t always work.
• If you have 2.4 GHz clients your network, the coverage area after FRA runs could change dramatically. Depending on how often you have FRA run, this can lead to a less stable network. I know Devin Akin (@DevinAkin) would say that 2.4 GHz is dead and probably should be at this point especially for voice clients, but I just did a job last week where they insisted using 2.4 GHz for voice.

• Instant AP Discovery Logic
• Modifying the Instant AP Hostname
• Configuring Zone Settings on anInstant AP
• Specifying a Method for Obtaining IP Address
• Configuring External Antenna
• Configuring Radio Profiles

Enabling Flexible Radio

• Dual 5 GHz Radio Mode
• Configuring Uplink VLAN for anInstant AP
• Changing the Instant AP Installation Mode
• Changing USB Port Status
• Master Election and Virtual Controller
• Adding IAP to Network
• Removing IAP from the Network
• Support for BLE Asset Tracking
• IoT Endpoints
• Zigbee-Based IoT
• Aruba Sensor Values
• Reporting Sensor Values
• HanVit Sensors
• SoluM ESL Gateway
• ZF Openmatics Support for ZF BLE Tag Communication
• Intelligent Power Monitoring
• Transmit Power Calculation support

This feature allows the AP to seamlessly switch between modes where the radio resources are either combined in a single 2x2 radio or separated into two 1x1 radios.

You can configure the flexible radio in the following modes:

5 GHz Gigahertz. mode: acts as a single radio operating on 5 GHz Gigahertz. band Band refers to a specified range of frequencies of electromagnetic radiation.

2.4 GHz Gigahertz. mode: acts as a single radio operating on 2.4 GHz Gigahertz. band Band refers to a specified range of frequencies of electromagnetic radiation.

2.4 GHz Gigahertz. and 5 GHz Gigahertz. mode: acts as two radio interfaces, one operating on 5 GHz Gigahertz. band Band refers to a specified range of frequencies of electromagnetic radiation. , and the other on the 2.4 GHz Gigahertz. band Band refers to a specified range of frequencies of electromagnetic radiation. . By default, the flexible radio is set to this mode.

AP-203H , AP-203R , and AP-203RP access points have one radio each, wherein each radio operates on two bands Band refers to a specified range of frequencies of electromagnetic radiation. . When the flexible radio mode is at 2.4 GHz Gigahertz. or 5 GHz Gigahertz. , the radio operates on one band Band refers to a specified range of frequencies of electromagnetic radiation. and the Instant AP broadcasts 16 different SSIDs Service Set Identifier. SSID is a name given to a WLAN and is used by the client to access a WLAN network. . However, when the flexible radio mode is at 2.4 GHz Gigahertz. and 5 GHz Gigahertz. , the radio operates on both the bands Band refers to a specified range of frequencies of electromagnetic radiation. and the Instant AP broadcasts only 8 SSIDs Service Set Identifier. SSID is a name given to a WLAN and is used by the client to access a WLAN network. for each band Band refers to a specified range of frequencies of electromagnetic radiation. , even if more than 8 SSIDs Service Set Identifier. SSID is a name given to a WLAN and is used by the client to access a WLAN network. are configured. The SSIDs Service Set Identifier. SSID is a name given to a WLAN and is used by the client to access a WLAN network. with an index value from 0 to 7 will be broadcasted.

You can configure the Flexible Radio parameter using the WebUI or the 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. :

In the Old WebUI

To configure flexible radio:

1. On the Access Points tab, click the Instant AP to modify.

2. Click the edit link.

3. Click the Flexible Radio tab.

4. Specify the Mode from the drop-down list.

5. Click OK .

6. Reboot the Instant AP .

In the New WebUI

1. Navigate to Configuration > Access Points .

2. Click the Instant AP to edit.

5. Click Save .

6. Reboot the Instant AP

To configure the flexible radio mode:

(Instant AP)# flex-radio-mode <mode>

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Viten Patel

A technology blog tailored towards Wireless (802.11) and other related technologies

Cisco Wireless Best Practices Flexible Radio Assignment (FRA)

Published by Viten Patel on December 5th, 2016

• Cisco Wireless
• Cisco Flexible Radio Assignment
• Cisco Dual 5Ghz
• Cisco Dual 5Ghz Wi Fi
• Cisco Wireless Best Practices Flexible Radio Assignment Fra