III. Wireless LAN

Wireless LAN Troubleshooting

Products:
Vigor 2820
Keywords:
2.4GHz
Access Point
Distance
Interference
Show all

Location Advice

  1. Do remember that coverage will vary hugely from one location to another. Factors which can affect this include building structure, wall/ceiling materials or thickness, embedded materials or cabling, adjacent objects/furniture etc. Figures quoted for wireless coverage are always 'ideal' so whilst achievable in the ideal environment, your own performance will vary - i.e. don't expect anything like "200 Metres" unless you are on a football pitch, in a vacuum.
  2. Location of Base Station. The Wireless base station (your Vigor router) should be sited in the most effective position - i.e. where it gives the best coverage for all locations that you want to use Wireless clients in. This isn't necessarily the most convenient location of course.
  3. The router can be wall mounted (use the screws supplied), or placed on a desk, shelf or table. The aerials should be vertical normally but you can experiment in case a different orientation gives you better coverage in your particular location.
  4. Avoid sources of interference - for example microwave ovens, DECT phones and particularly BlueTooth&qtrade; devices, but also metallic objects like filing cabinets.
  5. If you have purchased the optional high-gain aerials for your router, compare performance with the original aerials to confirm if they are providing an advantage.

Troubleshooting

  1. Try changing channels - if a neighbour or other devices are interferring, change from the router's default wireless channel (7) to another. This is done from the Wireless Setup menu on the router. You do not need to set the channel on the wireless clients - they should scan automatically (unless you have actually manually fixed the wireless client to a specific channel).
  2. Ensure that the router's aerials are firmly connected to the aerial sockets; they should be snugly thumb tightened. Do not over-tighten or let the socket turn in the case.
  3. Check that the wireless client adaptor (e.g. PCMCIA card or USB adaptor) is not clashing with another adaptor, for example a Bluetooth interface drivers or older WLAN device drivers.
  4. Your Wireless LAN client adaptor might not support WPA2, in which case you might need to configure the router's WLAN profile as WPA-PSK/TKIP manually if you are using Windows XP SP2 clients. Windows XP SP2 adds the WPA2 protocol but the wireless zero configuration may try to connect with an incorrect encryption type (WPA-PSK/AES or WPA2-PSK/TKIP). For WPA only, WPA-PSK with TKIP should be selected.
  5. Some Vigor models support mixed WPA/WPA2 mode, but some wireless client devices do not (notably XBox360™). For compatibility with such devices, you need to specifically force WPA-only mode. Do this from the router's telnet interface. Once telnetted to the router, enter the command: wl wpa 3 Note, that second character is a lower case L not a digit 1.
  6. Intermittent dropping of signal/connection to WLAN clients :
    • Check your router is running the very latest firmware; you can download it from this site. Later firmware may contain performance enhancements or compatibility improvements.
    • Relocate the router and/or client PC temporarily and see if the problem improves; if so check for sources of interferrence/obscruction as mentioned earlier.
    • Disable the more advanced wireless facilities (WEP, 802.1x, SSID Stealthing) temporarily to see if that resolves the problem.
    • If you have an 802.11g compatible router, within the router setup, try fixing the WLAN protocol to either 802.11b or 802.11g (rather than both or auto). Try doing the same on the setup utility for your wireless adaptor.
    • There are some WindowsXP known problems covered by the MS knowledgebase, so check if those make any difference from here or here.
    • Check that you have the latest and correct drivers for your WLAN client device; check the manufacturer's web site for those. A common cause of problems is older WLAN drivers. If you have an Intel or HP based WLAN interface on your PC, these links may have later drivers: Intel / HP / Atheros
    • Some users report that disabling the Windows 'Wireless Zero Configuration' utility, which is responsible for scanning for wireless access points can improve reliability of wireless connections (sometimes due to the Windows utility and the wireless device's own utility interferring with each other. With the 'Wireless Zero Configuration' service disabled, you must use the WLAN client adaptors own utility. The service can be disabled in WindowsXP from Control Panel -> Administrative Tools -> Services and then locating the service in the panel like this. Disable the automatic startup and then re-boot. Alternatively, unticking the box "Use Windows to Configure my wireless Network Settings" in the network connection properties may be adequate to solve this clash.
    • In some instances, changing WindowsXP's authentication behaviour in SP1 has been found to be beneficial, by setting the PC to authenticate as 'machine only'. This is set from registry key : HKEY_LOCAL_MACHINE\Software\Microsoft\EAPOL\Parameters\General\Global\AuthMode where the current value is probably 0 or 1. Try setting it to 2. Do not use regedit unless you understand what you are doing and know how to change it back afterwards if it makes no difference.
    • On Laptops/Notebook PCs with the Intel2100 WLAN chipset, there can be an issue with Windows Power Saving mode; the WLAN adaptor ceases transmission automatically to save power. Intel document the problem this can cause here. If you set the feature on your notebook to CAM (continually aware mode) it may alleviate the problem.
    • If your laptop uses the Intel 2200BG WLAN chipset, update your drivers here or here, depending on the chipset/interface you have.
    • Other WLAN adaptors also have power saving modes, which are useful normally, but if yours is cutting out when it shouldn't, disable the feature on the client adaptor :
      Wireless LAN Adaptor Power Save Mode
  7. Why don't I have WDS or WPA2 options on my router menu?This most likely indicates that your router model or firmware does not support the feature. If you have the latest firmware installed and the menu option still isn't there, then you do not have supporting hardware. WLAN Hardware version

    For the Vigor2600 series, you can check your router hardware version from the web interface. Generally, all Vigor2600 models shipped since Feb 2005 will have later hardware however this does not necessarily mean your particular model supports WDS/WPA (please refer to product's official UK specification). You will also require the latest router firmware for your model to add the WDS/WPA2 features. The last digit, after the firmware, version digits is the hardware version. For an explanation of WDS click here.

  8. Using WPA2 on XBox360™

The XBox360™ supports WPA but not WPA2, however the chipset itself does. This means that negotiation with the wireless router can fail, when the two devices agree on WPA2, but the XBox360™ cannot support it. On new Vigor models, a command is available from Telnet to force the router to use WPA mode and not WPA2.

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