Wireless LAN Troubleshooting Tips
Posted by Roy Panetta on 23 April 2019 04:17 PM

This document provides troubleshooting tips to help resolve some wireless network issues.

Slow wireless connections

1. Check for Channel interference and choose a less congested channel.

Nearby wireless routers or Access Points may be using a neighbouring wireless channel that will cause congestion when a large number of devices are transmitting data. This is more noticeable with the 2.4GHz Wi-Fi band.

Also check the "Interference Monitor" under the Diagnostic menu in the Access Point or find neighbouring SSIDs through "AP discovery" in the wireless router. Then choose a less congested channel to reduce interference.

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2. Enable Band Steering feature to encourage dual-band capable clients to stay on the 5GHz band.

The 5GHz wireless band provides faster data rates at shorter distances and is typically much less congested than the 2.4 GHz wireless band. Let wireless clients connect to 5G band to get better performance.

3.  Locate Access Points/wireless routers away from the interference.
Ceilings, walls or metal materials will decrease the Wireless signal strength. Moving the Access Points away from the floor, walls and metal objects such as shelving or other metallic furnishings will make an improvement.


Wireless clients disconnecting frequently

1. Note the device MAC address and search it in the Syslog.

A [DrayRS] message in syslog, indicates that AP-assisted Client Roaming has disconnected the wireless client. When the wireless client meets the criteria set in the roaming page, the Access Point/router will disconnect it. To troubleshoot, disabling this function first to verify that this is the cause of the problem and adjust parameters to suit the wireless network environment.

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More details are available in this FAQ to help adjust the configuration for Roaming,

Wi-Fi Roaming with VigorAP
https://www.draytek.com/support/knowledge-base/5764

When Band Steering is enabled but wireless clients still connect to 2.4G

When Band Steering is enabled, the Access Point will stop hand-shaking for a few seconds while the wireless client is trying to connect to the 2.4G band. The default time delay is 15 seconds, but can be modified in the Band steering setup page. When we find wireless clients still connect to 2.4G instead of 5G, can check the information in the syslog.
For example, the wireless client tries to connect 2.4G, the Access Point will block the connection until the time period has expired.

Jan  1 17:48:46  syslog: [BandSteering] ==> check 2.4G connection failed. client (30:07:4d:3d:20:f5) is not allowed to connect 2.4G (Elapsed time:15, Check time:15, Hold time:15).
Jan  1 17:48:47  syslog: [BandSteering] ==> check 2.4G connection failed. client (30:07:4d:3d:20:f5) is not allowed to connect 2.4G (Elapsed time:16, Check time:15, Hold time:15).
Jan  1 17:48:47  kernel: 30:07:4d:3d:20:f5 had associated successfully

If the wireless client is expected to connect to 5G it does not:

  1. Check to see that both 2.4G and 5G bands are visible from the wireless client when disabling Band Steering by putting them in separate SSIDs
  2. Is 5GHz supported on wireless client? Try to check the compatibility between AP and wireless client.
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