Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

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Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

Mesh backhaul RRM

Updated: April 10, 2026

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Explains how mesh backhaul RRMs optimize wireless mesh network performance by dynamically selecting the best backhaul channels and reducing interference.

A mesh backhaul RRM is a wireless network optimization mechanism that

  • continuously evaluates channel conditions to identify the least congested backhaul channels

  • reduces interference and enhances mesh network stability, and

  • automates channel selection for root and mesh access points (APs).

Root access points (RAPs) choose backhaul channels to operate in mesh networks. Until Cisco IOS XE Cupertino 17.8.1, this operation occurred by an explicit configuration, a least congested scan during RAP boot time, during the initial radio resource management (RRM) run without mesh access points (MAPs) connected, or a backhaul channel that was chosen at random. As a result, a poor backhaul channel selection resulted in poor performance.

From Cisco IOS XE Cupertino 17.9.1 onwards, RRM DCA is run on mesh backhaul, in auto mode, in FlexConnect or centralized networks. For APs that do not have dedicated (RHL) radios, DCA is triggered by running commands in the privilege EXEC mode.

RRM continuously evaluates the channel conditions to ensure that the network utilizes the least congested channels. The network uses the transmission static power if it is configured, or falls back to the default level. This is supported on APs that have dedicated radios to scan channel conditions, without any user perceptible interruption to the mesh network traffic.

In the mesh backhaul RRM feature, the RRM DCA decides all the downlink channels in a steady network. However, if an AP detects a change in its uplink roam or radar detection response, the AP chooses the best downlink to converge faster.

APs choosing the best possible downlink is limited to serial backhaul enabled APs only.

To avoid a poor channel backhaul selection, from Cisco IOS XE Dublin 17.14.1 onwards, the RRM DCA optimizes the RAP backhaul radio channel of a mesh subtree by considering the noise, interference, load, and the RF parameter measurements only from the RAP. The RRM DCA on Mesh Backhaul feature enables DCA to make better channel assignment for a mesh subtree, by having continuous measurements and inputs from the whole mesh tree required to run DCA.

To enable RRM DCA on a full mesh tree run the wireless mesh backhaul rrm auto-dca command. To trigger DCA once, run the ap dot11 [5ghz | 2.4 ghz] rrm channel-update mesh command.

To understand what happened during a DCA run on the mesh backhaul, use the show wireless mesh rrm dca status and show wireless mesh rrm dca changed commands.

Note

  • In a topology with mixed APs (RF ASIC capable and non-capable APs), only inputs from the RF ASIC capable APs apply for auto-dca .

  • All mesh APs in a subtree should be configured to belong to the same site-tag for DCA to work properly.

  • This feature is limited to RF ASIC capable APs, such as Cisco Catalyst 9124 Series APs and Cisco Catalyst 9130 Series APs.

Radio Resource Management on mesh

Radio resource management (RRM) features are wireless network management functions that

  • enable real-time RF management of the wireless network

  • monitor lightweight APs for traffic load, interference, noise, and coverage, and

  • operate automatically through embedded controller software.

The RRM measurement in the mesh AP backhaul is enabled based on these conditions:

  • Mesh AP has the Root AP role.

  • Root AP has joined using Ethernet link.

  • Root AP does not serve any child AP.

Configure RRM on mesh backhaul (CLI)

RRM measurement in the mesh AP backhaul is enabled if your access point meets these conditions:

  • Mesh AP has the Root AP role.

  • The Root AP has joined the network using an Ethernet link.

  • Root AP does not serve any child AP.

Complete the steps to enable RRM in the mesh backhaul:

Procedure

1.

Enter global configuration mode.

Example:

Device# configure terminal
2.

Configure RRM on the mesh backhaul.

Example:

Device(config)# wireless mesh backhaul rrm

RRM is enabled on the mesh backhaul for APs. 

Device# configure terminal
Device(config)# wireless mesh backhaul rrm

Configure RRM channel assignment for root access points globally

Configure Radio Resource Management (RRM) channel assignment policies for all root access points. This configuration optimizes wireless performance, minimizes interference, and maintains network stability across your deployment.

Procedure

1.

Enter global configuration mode.

Example:

Device# configure terminal
2.

Configure RRM for mesh backhaul.

Example:

Device(config)# wireless mesh backhaul rrm
3.

(Optional) Configure auto DCA for RF Application Specific Integrated Circuit (ASIC) integrated RAPs.

Example:

Device(config)# wireless mesh backhaul rrm auto-dca

All RAPs adopt the configured RRM channel assignment settings globally. This change results in improved channel distribution, reduced interference, and more reliable wireless connectivity across the network. 

Device# configure terminal
Device(config)# wireless mesh backhaul rrm
Device(config)# wireless mesh backhaul rrm auto-dca

Complete these steps to configure the initial channel assignment of the RAP in privileged EXEC mode through RRM and to initiate channel selection for each bridge group.

Procedure

1.

Enter privileged EXEC mode.

Example:

Device> enable
2.

Initiate the update of the 802.11, 802.11a, or 802.11b channel selection for every mesh Cisco AP.

Example:

Device# ap dot11 {24ghz | 5ghz | 6ghz} rrm channel-update mesh
3.

Initiate the update of the 802.11, 802.11a, or 802.11b channel selection for mesh AP in the bridge group.

Example:

Device# ap dot11 {24ghz | 5ghz | 6ghz} rrm channel-update mesh bridge-group bridge-group-name

RRM completes the channel assignment for the RAP in privileged EXEC mode. 

Device> enable
Device# ap dot11 5ghz rrm channel-update mesh
Device# ap dot11 5ghz rrm channel-update mesh bridge-group cisco-bridge-group

Configure RRM channel assignment for an AP

Assign RRM channels to an AP. This action helps you optimize wireless channel usage and reduce interference.

Procedure

1.

Enter privileged EXEC mode.

Example:

Device> enable
2.

Trigger the RRM DCA process for your AP.

Example:

Device# ap name Cisco-ap-name dot11 {24ghz | 5ghz | 6ghz} rrm channel update mesh

After you trigger the process, the system starts the RRM DCA process and updates the channel assignment for your selected radio band.

Device> enable
Device# ap name Cisco-ap-name dot11 5ghz rrm channel update mesh

RRM DCA status verification

Verify the RRM DCA status for mesh access points using specific commands and understand the output differences between manual and automatic DCA triggers.

To view the status of the DCA that is run for mesh APs, run this command: 
Device# show ap name Cisco-AP config general | inc Mesh
Mesh profile name                               : default-mesh-profile
Mesh DCA Run Status:                            : Not Running
Last Mesh DCA Run                               : 02/07/2022 01:21:56
To verify the status of the last DCA run per radio, run this command: 
Device# show wireless mesh rrm dca status
Note

The output for the show AP config general | i Mesh and the show AP name <AP name> config general | i Mesh command displays only the status for manual RRM DCA triggers performed with the AP name <AP name> dot11 RRM channel update mesh command.

The output for the show AP config general | i Mesh and the show AP name <AP name> config general | i Mesh commands, does not update if only the global mesh RRM DCA is enabled (auto-DCA).

Dynamic frequency selection

A dynamic frequency selection (DFS) is a wireless communication protocol that

  • enables radio devices to detect radar signals

  • requires devices to cease transmission when radar is detected, and

  • requires selecting and monitoring a new channel before resuming transmission.

Regulatory bodies enforce DFS to prevent interference with radar services in shared frequency bands by unlicensed wireless devices.

To protect radar services, regulatory bodies require devices on newly opened frequency sub-bands to operate using DFS. Your radio device must detect radar signals as required. If a radar event is detected in any AP within a sector, mesh access points immediately switch channels to maintain compliance.

For instance, When a radio detects a radar signal, the radio should stop transmitting for at least 30 minutes to protect that service. The radio should then select a different channel to transmit on, but only after monitoring it. If no radar is detected on the projected channel for at least one minute, the new radio service device can begin transmissions on that channel.

Configure dynamic frequency selection (CLI)

Configure dynamic frequency selection (DFS) on your device to enable radar detection and meet DFS requirements.

DFS specifies the types of radar waveforms that should be detected and the timers that must be used for operation in the DFS channel.

Procedure

1.

Enter global configuration mode.

Example:

Device# configure terminal
2.

Configure a mesh profile and enter mesh profile configuration mode.

Example:

Device(config)# wireless profile mesh profile-name
3.

Enable DFS.

Example:

Device(config-wireless-mesh-profile)# full-sector-dfs
Note

DFS functionality allows a MAP that detects a radar signal to transmit this information to the RAP. The RAP treats this as a radar detection and moves the sector. This process is called the coordinated channel change. The coordinated channel change feature is always enabled on Cisco Wave 2 and newer APs. You can disable this feature only on Cisco Wave 1 APs.

Dynamic Frequency Selection is enabled for your mesh profile. Your mesh profile is now ready to operate and meets radar detection requirements.

Device# configure terminal
Device(config)# wireless profile mesh dfs-mesh-profile
Device(config-wireless-mesh-profile)# full-sector-dfs

Spectrum Intelligence for mesh

A Spectrum Intelligence feature is a wireless network monitoring capability that

  • scans 2.4 GHz and 5 GHz bands for non–Wi-Fi radio interference

  • provides device and air quality reports using Cisco CleanAir technology, and

  • includes mitigation features like Event-Driven Radio Resource Management (EDRRM) and Persistent Device Avoidance (PDA) that require CleanAir data.

The Spectrum Intelligence feature supports both client serving and monitor modes. CleanAir technology in mesh backhaul and access radios generates Interference Device Reports (IDR) and Air Quality Index (AQI). In mesh networks, you use mitigation features with client-access radios in the same way as with non-mesh networks. However, in backhaul radios, reports are controller-only and do not trigger ED-RRM actions. You cannot enable or disable CleanAir on mesh APs (MAPs) because configuration options are not available.

For more information about Spectrum Intelligence, see Configure spectrum intelligence (CLI) section.