Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.x

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Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.x

Link test

Updated: September 14, 2026

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Explains procedures for testing and assessing mesh backhaul link quality and performance, including GUI and CLI-based link test configurations.

A link test is a radio communication diagnostic tool that

  • determines the radio link quality between two devices

  • supports both ping and CCX test types for different directions, and

  • allows both APs and clients to act as initiators and responders.

Two types of link-test packets are transmitted during a link test: request and response. Any radio that receives a link-test request packet fills in the appropriate text boxes. It then echoes the packet back to the sender with the response type set. The radio link quality in the client-to-access point direction can differ from that in the access point-to-client direction. This difference occurs because transmit power and receive sensitivity are distributed asymmetrically on both sides.

Types of link tests

The two types of link tests that you can perform are:

  • Ping link test: With the ping link test, the controller tests link quality in the client-to-access point direction. The controller polls the RF parameters of the ping reply packets received by the AP to determine the client-to-access point link quality.

  • CCX link test: With the CCX link test, the controller can also test the link quality in the access point-to-client direction. The controller sends link-test requests to the client. The client records RF parameters, such as received signal strength indicator (RSSI) and signal-to-noise ratio (SNR), in the response packet. Both requestor and responder roles exist on the AP and controller. You can initiate a link test from the AP, controller, or a CCX v4 or v5 client.

Network administrators can validate wireless mesh backhaul connectivity and signal strength with this task. Running a link test enables proactive identification of performance issues, ensures reliable mesh network operation, and helps troubleshoot weak connections.

Procedure

  1. Choose Monitoring > Wireless > AP Statistics > General.

  2. Select the Access Point.

  3. Choose Mesh > Neighbor > Linktest.

  4. Select the desired values from the Date Rates, Packets to be sent (per second), Packet Size (bytes), and Test Duration (seconds) drop-down lists.

  5. Click Start.

You can see the detailed link test results for the selected mesh backhaul connection.

To initiate a link test between neighbor mesh APs, complete these steps.

Note

Use the test mesh linktest mac-address neighbor-ap-mac rate data-rate fps frames-per-second frame-size frame-size command to perform link test from an AP.

Procedure

  1. Enters privileged EXEC mode.

    Example:

    Device> enable

  2. Set the link test parameters.

    Example:

    Device# ap name ap-name mesh linktest H.H.H data-rate packet-per-sec packet-size test-duration

    • H.H.H: Specify the destination AP MAC address.

    • data-rate: Specify the data rates in Mbps. The values are 1, 2, 5, 6, 9, 11, 12, 18, 24, 36, 48, 54, 108, or m0 through m15.

    • packet-per-sec: Specify the packets to be sent per second. The range is from 1 to 25,000.

    • packet-size: Specify the packet size in bytes. The range is from 1 to 1,500.

    • test-duration: Specify the test duration in seconds. The range is from 10 to 300.

The system displays test results, including throughput, loss, and latency metrics, to verify link quality between access points.

Device> enable
Device# ap name ap1 mesh linktest F866.F267.7DFB 24 234 1200 200