III. Wireless LAN

Troubleshooting 5GHz Wi-Fi connectivity issues

Products:
Vigor 2762
Vigor 2765
Vigor 2862
Vigor 2865
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Keywords:
5ghz
802.11ac
ap-assisted roaming
band steering
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The 5GHz WiFi connection comes with it's strengths and limitations. With more band-width and a clearer frequency space, it provides much faster data transfer and is typically able to maintain a more stable signal, with less radio interference, when compared with 2.4GHz Wireless.
One potential drawback however, is that 5GHz WiFi's range can be lower as the 5GHz signal is less able to pass through surfaces than 2.4GHz wireless. With proper planning, 5GHz 802.11n and 802.11ac wireless access points provide a faster and more responsive connection to clients than 2.4GHz wireless on its own.

This guide helps with ways to maximize the performance of the 5GHz wireless band on Draytek routers with 802.11ac and Dual Band wireless. The steps below can be helpful if you are seeing poor performance or if your WiFi connection keeps dropping out or you cannot connect to the 5GHz WiFi.

1. Ensure your WiFi router or access point is running the latest firmware version

We always recommend the use of the latest firmware for your product to ensure that you have the latest features as well as vital security improvements. Sometimes, these improvements increase performance. To check for the latest firmware version for your device, visit our Downloads page.

2. Adjust the positioning and orientation of the router or access point

For situations where the 5GHz WiFi signal is poor or the WiFi client cannot find the router's WiFi signal, you can simply adjust the position and orientation of the wireless router or access point to improve the 5GHz signal strength. Experiment with different locations to get the best performance. Also adjust the positioning of the router's and AP's antennas for obtaining better signal, for instance moving the antennas to a 45 degree angle can help with improving wireless signal strength above and below the AP.

3. Use WPA2/PSK for authentication

If you have a WiFi device that will not connect to the router's WiFi, check that the SSID's security mode is set to WPA2/PSK. This is currently the most secure WiFi authentication form supported by all latest WiFi devices, we recommend this mode for WiFi authentication. To set this up, go to  [Wireless LAN] > [Security], and for each of the configured SSIDs select WPA2/PSK as the mode.
Using WPA/PSK or WEP will significantly decrease wireless speeds for compatibility purposes.

4. Setup unique SSID names for for the 2.4GHz and the 5GHz bands

Some WiFi devices may not cope well with a single SSID for the  2.4GHz and the 5GHz frequencies. The device may exhibit the following symptoms;

  • Device is unable to connect to the router or AP.
  • Device may lose WiFi connection frequently.
  • WiFi connection speed may be lower than expected.
  • Device will not connect to the 5GHz band even when it's close to the router.

This can be resolved by assigning different network names to the SSID's on the the 2.4GHz and the 5GHz bands. This can be setup on the [Wireless LAN] > [General Setup] page.

5. Use non-DFS channels

In the 5GHz spectrum, channels 52 to 140 are subject to Dynamic Frequency Selection (DFS) requirements. A Wireless access point will stop broadcasting and communicating with wireless clients during the DFS scanning period, which must be checked every 24 hours. This could appear to be an occasional loss of connectivity with the access point, during this scanning period.

To avoid this periodic loss of connectivity, when using "Auto" wireless channel mode, you can exclude the impacted channels (52 to 140) in [Wireless LAN (5GHz)] > [Advanced Settings].

If using a fixed wireless channel, try channels 36 to 48, as those are non-DFS channels and don't need to do any scanning before use.

6. Update your drivers

Occasionally vendors update the device software. Check if your vendor has newer firmware or drivers. These updates can improve performance and reliablity.

7. Add an additional  wireless access point or repeater

If you find that your 5GHz WiFi coverage is insufficent, you can extend the range of your 5GHz WiFi by adding another Wireless Access Point at the other end of your premises. This will allow you to double the coverage area. If possible, connect the additional WAP by Ethernet cable for the best performance.

Troubleshooting Problems

The following section outlines some of potential problems a user may experience, including both symptoms and troubleshooting steps.

I. Band Steering is enabled but wireless clients still connect to 2.4GHz

When Band Steering is enabled, AP will stop hand-shaking for a few seconds when wireless client is trying to connect 2.4GHz band. This waiting time is set as 15 seconds in default, it can be modified on the Band Steering setup page. When we find wireless clients still connect to 2.4GHz instead of 5GHz, we can check the information from the syslog. For example, the wireless client tries to connect 2.4GHz, AP will block the connection until the time is 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 5GHz but actually it's not. We can check;

1. Can the wireless client see both 2.4GHz and 5GHz when Band Steering is disabled and the SSIDs have different names? Band Steering requires that both bands use the same SSID.

2. Is 5GHz supported on the wireless client? Try to check the compatibility between AP and wireless client.

3. Set preferred band to 5GHz in the wireless client's driver settings:

5GHZ prefered

II. Wireless clients are disconnecting frequently

Note the MAC address of the client and search for it in the  router or AP's Syslog diagnostic messages. Setup Syslog

If you see a [DrayRS] message in syslog, it means that AP-assisted Client Roaming has disconnected the wireless client to allow it to re-connect to a closer AP with better signal. When the wireless client meets the criteria set in the roaming page, the AP/router will disconnect it, we recommend disabling the function first to clarify the problem and adjust the parameters to suit the wireless network environment.

roaming

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