Background:

 

This post introduces several typical wireless roaming issues along with their corresponding troubleshooting recommendations.

 

This Article applies to:

 

All Omada EAPs.

 

Failure Type_1: Roaming Failure

 

Description:

 

Roaming failure occurs when a wireless client disconnects or fails to connect to a new AP during the handoff process.

 

Possible Causes:

 

1. SSID Mismatch – Different SSID configurations across APs

2. Poor Coverage – Discontinuous signal or improper power settings

3. Interference – Same-SSID signals from non-EAP networks

 

Troubleshooting Steps

 

Step 1: Verify WLAN Group Consistency

 

Check whether the WLAN Group configurations of all APs are the same. If the SSID of another AP is different from the SSID to which the STA is currently connected, roaming will fail. As shown in the figure below, under Devices → Config → WLANs, it was found that the SSID to which the STA is currently connected is "demo_ssid", which does not match the SSID of another AP, resulting in failed roaming.

 

 

Step 2: Check Signal Coverage Continuity

 

Check whether the signal coverage of the two APs before and after roaming is continuous. If the distance between the two APs is too far, the wireless clients may temporarily disconnect and then reconnect while moving due to discontinuous signal coverage, resulting in roaming failure.
1. Tools such as inSSIDer and WiFi Analyzer can be used to measure the signal strength and coverage of the APs.
2. If the signal coverage between APs is confirmed to be discontinuous, you can increase the AP transmit power or add new APs to ensure continuous coverage.

To increase the AP transmit power, please go to Devices → Config → Radios →Tx Power (EIRP):

 

Step 3: Detect Same-SSID Interference

 

Check whether there are any SSIDs with the same name from other networks in the WLAN environment (e.g., your router's SSID), as this may cause the wireless clients to disassociate from EAP and result in roaming failure.

 

Failure Type_2: Ping-Pong Roaming

 

Description:

 

Ping-pong roaming refers to the phenomenon where a wireless client repeatedly roams back and forth between two EAPs.

 

Possible Causes:

 

1. Weak signal coverage overlap caused by improper EAP placement
2. Abnormal client behavior due to internal algorithm issues

 

Troubleshooting Steps

 

Step 1: Multi-Client Validation

 

It is recommended to first verify using multiple clients to confirm whether ping-pong roaming occurs across different devices.

 

Step 2: Adjust AP Transmit Power

 

Improper AP deployment may cause overlapping weak signal coverage areas. Increasing AP transmit power can help mitigate this issue.

Recommended Actions: Navigate to Devices → Detail → Radios → Tx Power to view the current power setting for a specific AP, and adjust the transmit power to a higher level

 

Step 3: Enable Lock to Wireless Device Feature

 

This feature forces a wireless client to associate only with a designated AP, preventing repeated associations across multiple APs. Navigate to Client → Config → Lock To Wireless Device

 

 

Note: 

1. To use this function, ensure your device is using the device MAC rather than a random MAC. Otherwise, the function may not take effect. 

2. Enabling this feature may affect other roaming scenarios.

 

Failure Type_3: Sticky Roaming

 

Description:

 

Sticky roaming occurs when a wirless client remains associated with a weak-signal AP for an extended period despite the presence of a clearly better target AP. This may be caused by an insufficiently intelligent roaming decision algorithm or overly conservative STA behavior, resulting in the wireless client persistently operating under weak signal conditions.

 

Possible Causes:

 

1. Improper EAP deployment.
2. The wireless client does not support 802.11k/v protocol.
3. The wireless client exhibits passive probing behavior.

 

Troubleshooting Steps

 

Step 1: Resolve Signal Overlap with Power/Placement Adjustments

 

To address signal overlap between APs, use WiFi signal analysis tools to detect coverage overlap areas. Adjust power settings or AP placement to eliminate unnecessary overlap. For example, when two EAPs are installed too close, certain areas may receive signals from both devices. In such cases: we can reduce the transmit power of one EAP.

 

Step 2: Enable AI Roaming and FastRoaming to Guide Roaming

 

Navigate to Settings→ Site→ Wireless Features→ Enable Fast Roaming→ Enable AI Roaming:

 

 

Note: AI Roaming is only supported after controller v5.14 and above.

 

Step 3: Enable 802.11r

 

Navigate to Settings→ Wired&Wireless → Networks WLAN, Edit the SSID that having roaming issues, go to Advanced Settings, enable 802.11r:

 

 

Note:

1. 802.11r only helps when both the AP and the wirless clients have 802.11r capabilities. Otherwise, it may cause some unexpected issues.

2. Currently 802.11r does not support WPA3-Enterprise encryption.

 

Recommended Threads:

 

How to optimize wireless performance of EAP products

 

 

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