Troubleshooting WLANs
A common and very efficient troubleshooting method can be broken into 6 main steps:
| 1. Identify the Issue |
| The first step when troubleshooting is of course to identify the problem and the source. Tools can always be useful but a conversation with the user is often a good start. |
| 2. Create a Theory of Possible Causes |
| After speaking to the user and identifying the issue, you can try to establish a theory of possible causes. This step usually brings forward more than just a few possible causes of the issue. |
| 3. Test the Theory to Determine Cause |
| Based on the Possible and now Probable causes, you should test your theories to determine which one is the root of the problem. At times one will often apply a quick “fix” to test and see if the problem is solved. If a quick “fix” does not correct the issue, further research might be required to establish the exact cause. |
| 4. Create a Plan of Action and Implement the Solution |
| After finding the exact root of the problem, you should create a Plan of Action on how to resolve the problem and implement the solution. |
| 5. Verify System Functionality and Implement Preventive Measures |
| After fixing the issue, you should verify the full functionality of the network, and if applicable, preventive measures should be implemented. |
| 6. Document Findings, Actions, and Outcomes |
| After troubleshooting and rectifying an issue, you should always document your findings, actions, and outcomes. This is step is crucial for future reference. |
Primarily, you should determine how many devices are experiencing the issue on the network. If the problem is only with one device, you should always start the troubleshooting process at that very device.
On the other hand, if there is a problem with multiple devices on the network, you should start the troubleshooting process at the device to which all those devices are connected.
The trick is to eliminate one problem at a time.
Wireless Client not Connecting
If there is totally no connectivity, do the following procedures:
- Confirm the network configuration on the PC via the “ipconfig” command and confirm that the PC has received an IP Lease from the DHCP server or is configured with a static IP Address.
- Confirm that the device is able to connect to the wired network. If so, connect the device and ping a known IP Address.
- If you deem necessary, re-install drivers as required for such a client. It might be also necessary to try a different WiFI NIC.
- If the WiFI NIC of the client is functional, check the security mode and encryption settings. If the security settings do not match, the client won’t be able to access the WLAN.
If the PC is functional but the Wireless connection is not performing well, do the following procedures:
- How far away is the PC from the Access Point? Is the PC out of the BSA/planned coverage area?
- Confirm the channel settings on the wireless client. If the SSID is correct, the client should detect the right channel.
- Confirm if there are no other devices in the area that are interfering with the 2.4GHz band like for example Microwave ovens, cordless phones, and potentially rogue APs.
We also need to make sure that all the devices are actually in place and determine whether they are powered up or not.
Finally, check the links between cabled devices and look for damaged or missing cables and/or connectors. If everything is in place, try pinging the devices including the AP itself. If you have no success in doing so it might be that something is wrong with the AP itself or the configuration.
When we know for sure that the User’s PC is not the source of the issue, and also that the physical status of all devices is confirmed, we should then start investigating the performance of the Access Points.
Troubleshooting Slow Network Issues
If you would like to optimize and increase the bandwidth of 802.11 dual-band Routers and Access Points you can opt for either of the following options:
| Upgrade Wireless clients |
| Old devices (802.11b/g/n) can slow the entire Wireless Network. For best performance, all wireless devices should support the same highest acceptable standard. The current highest standard is 802.11ac but that is slowly changing to be 802.11ax in the near future. |
| Splitting Traffic |
| A recommended and easy way to improve wireless performance is to split the Wireless Traffic between the 802.11n 2.4GHz band and the 5GHz band. In such a scenario, 802.11n or better can use both of the bands as 2 separate wireless networks to help manage and load balance traffic. 2.4GHz should be used for the most basic internet tasks (browsing, email, and downloads), therefore the 5GHz band should be used for Multimedia Streaming. |
There are multiple reasons for using a split-the-traffic methodology:
- A 2.4 GHz band may be suitable for just basic Internet traffic that is not time-sensitive.
- The bandwidth may still be shared with other nearby WLANs.
- The 5 GHz band is much less crowded than the 2.4 GHz band and is ideal for Multimedia Streaming.
- The 5 GHz band has more channels; therefore, the channel chosen is likely to be free of interference.
By default, dual-band Routers and Access Points use the same network name on both bands (2.4GHz and 5GHz) which is known as Band Steering. The simplest way to segment traffic is to switch off/disable Band Steering and rename on of the wireless networks. When using a separate name it will be easier to connect to the right network.
To improve the range of a wireless signal, make sure that the Wireless Router or Access Point is free of any obstructions, like for example furniture, gypsum partitions, and tall appliances. Such objects will absorb and block the signal and of course, shortens the WLAN range. If such objects cannot be moved it would be required to implement a WiFI Range Extender or deploy a powerline Wireless Technology method.
Upgrading Firmware
Most of the Wireless Routers and Access Points nowadays offer upgradable firmware. Such Firmware releases usually include hot-fixes for commonly encountered problems and bugs as reported by customers and will also mitigate security vulnerabilities which is crucial.
You should frequently check your hardware for any updated firmware releases.
When it comes to Access Points controlled through a WLC, usually there will be the ability to upgrade the firmware on all connected Access Points.
It’s also very common that clients will be temporarily disconnected from the WLAN until the upgrade completes. The appliance will have to reboot several times to install the required software before normal network operation is restored.