Fix: Stop WiFi Scanning When Connected (Easy Guide)

Have you ever experienced frustrating lag spikes while gaming or streaming, only to discover your WiFi latency is the culprit? It's a common issue, especially for those of us using Linux distributions like Debian with KDE Plasma. In this guide, we'll dive deep into identifying and resolving the problem of periodic WiFi scanning that can disrupt your network connection. Let's get started, guys!

Understanding the Issue: WiFi Latency Spikes

Experiencing WiFi latency spikes can be incredibly annoying. Imagine you're in the middle of an intense online game, and suddenly your ping skyrockets, causing lag and frustration. Or perhaps you're streaming your favorite show, and the video starts buffering intermittently. These disruptions can often be traced back to your system's periodic WiFi scanning behavior. But what exactly is this, and why does it happen?

At its core, periodic WiFi scanning is a process where your device actively searches for available wireless networks, even when you're already connected to one. This scanning is typically managed by the NetworkManager, a network management daemon commonly used in Linux distributions. While the intention behind this feature is to ensure seamless network switching and connectivity, it can sometimes lead to unexpected latency issues. The constant scanning consumes resources and can interfere with your current connection, resulting in those dreaded ping spikes.

NetworkManager plays a crucial role in handling your network connections. It automatically detects and connects to available networks, manages IP addresses, and handles various network configurations. However, its default settings might not always be optimal for every user. The periodic scanning, in particular, can be a double-edged sword. On one hand, it helps in quickly finding and connecting to new networks. On the other hand, it introduces latency spikes, especially if the scanning interval is too frequent. Understanding this trade-off is the first step in optimizing your WiFi performance.

The problem becomes more apparent when you start using tools like ping and iw event to monitor your network activity. The ping command is a classic tool for measuring the round-trip time for packets sent to a destination, giving you a direct measure of latency. You might notice that your ping times are generally low and stable, but then periodically jump up for a few seconds before returning to normal. This intermittent spike is a telltale sign of something interfering with your connection. Tools like iw event provide a more granular view of WiFi events, such as scanning activity, allowing you to correlate these events with the latency spikes you're observing.

Diagnosing the Problem: Tools and Techniques

To effectively tackle the issue of periodic WiFi scanning, you need to become a bit of a detective. Fortunately, there are several tools and techniques you can use to diagnose the problem and pinpoint the source of your latency spikes. As mentioned earlier, ping and iw event are your primary weapons in this battle. But how do you use them effectively?

Let's start with ping. This command sends ICMP echo requests to a specified destination and measures the time it takes for the replies to return. A consistent, low ping time indicates a stable connection, while intermittent spikes suggest interference or network congestion. To use ping for diagnosis, open your terminal and run the command ping <your_gateway_ip>. You can find your gateway IP by running ip route | grep default. Observe the output for any sudden increases in ping time. If you notice spikes occurring regularly, it's a strong indicator that something is periodically interrupting your connection.

For a more detailed view, iw event is your go-to tool. This command monitors wireless events, including scanning activities, association changes, and authentication attempts. By running sudo iw event, you can see a real-time stream of wireless events. Pay close attention to the events related to scanning. If you see frequent scan requests, especially when you're already connected to a network, it's likely that the NetworkManager is the culprit behind your latency spikes. Correlating these scan events with the ping spikes you observed earlier will solidify your diagnosis.

Another helpful technique is to monitor your system's resource usage. High CPU or memory usage can sometimes contribute to network latency. Tools like top or htop can provide a real-time view of your system's resource consumption. While periodic WiFi scanning itself shouldn't consume excessive resources, it's worth checking if other processes are contributing to the problem. If you notice a particular process spiking in CPU usage during the same time as your latency spikes, it might be interfering with your network connection.

Lastly, consider the possibility of interference from other wireless devices or networks. If you live in an area with many WiFi networks, your device might be constantly scanning for and trying to connect to different networks, leading to latency issues. Wireless devices like Bluetooth headphones or microwaves can also cause interference. Try disabling Bluetooth or moving away from potential sources of interference to see if it improves your connection stability.

Solutions: Disabling or Modifying WiFi Scanning

Once you've diagnosed the problem and confirmed that periodic WiFi scanning is indeed the cause of your latency spikes, it's time to implement a solution. There are several ways to tackle this issue, ranging from disabling scanning altogether to modifying the scanning frequency. Let's explore these options in detail.

The most straightforward approach is to disable WiFi scanning entirely. This will prevent your device from actively searching for new networks, eliminating the interference caused by scanning. However, this also means that you'll need to manually connect to new networks if you move to a different location. To disable scanning, you can modify the NetworkManager configuration file. Open a terminal and use a text editor (like nano or vim) to edit the file /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf. Add the following lines to the file:

[connection]
wifi.powersave = 2

This setting disables WiFi power saving, which also disables periodic scanning. Save the file and restart the NetworkManager service by running sudo systemctl restart NetworkManager. After restarting, your device will no longer scan for networks in the background.

If you don't want to completely disable scanning, you can instead modify the scanning frequency. This allows you to strike a balance between connectivity and performance. You can adjust the scanning interval using the iwconfig command. To set the scan interval to a longer period, say 300 seconds, run the command sudo iwconfig wlan0 scan interval 300, replacing wlan0 with your wireless interface name if it's different. Note that this setting is not persistent and will be reset upon reboot. To make it permanent, you can add this command to a startup script.

Another approach is to use the nmcli tool, the command-line interface for NetworkManager. You can modify the WiFi power saving settings using this tool. Run the command nmcli radio wifi off to disable WiFi radio scanning, or use nmcli radio wifi on to re-enable it. This method provides a more dynamic way to control scanning behavior without directly editing configuration files.

Consider using a static IP address for your network connection. When your device uses DHCP to obtain an IP address, it periodically sends out DHCP requests, which can contribute to network traffic and latency. By assigning a static IP address, you eliminate these requests and potentially improve connection stability. You can configure a static IP address through your network settings in KDE Plasma, or by manually editing the network configuration files.

Finally, always keep your wireless drivers up to date. Outdated drivers can sometimes cause unexpected behavior, including issues with scanning and latency. Check your distribution's package manager for any driver updates, and install them if available. Keeping your system updated is a good practice in general, as it often includes bug fixes and performance improvements.

Advanced Tweaks: Wpa Supplicant and Configuration Files

For those of you who want to delve even deeper into optimizing your WiFi performance, tweaking the Wpa Supplicant configuration and other system files can provide further improvements. Wpa Supplicant is a crucial component that handles the authentication and encryption of your WiFi connections. By fine-tuning its settings, you can potentially reduce latency and improve overall stability.

The main configuration file for Wpa Supplicant is usually located at /etc/wpa_supplicant/wpa_supplicant.conf. Before making any changes, it's always a good idea to back up the original file. You can create a backup by running sudo cp /etc/wpa_supplicant/wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf.bak. Now, open the file using a text editor and let's explore some useful tweaks.

One setting you might want to adjust is the scan_ssid parameter. By default, Wpa Supplicant will include the SSID (network name) in its scan requests. While this is necessary for hidden networks, it can sometimes cause issues with certain access points. If you're not using a hidden network, you can try setting scan_ssid=0 in the global section of the configuration file. This will prevent Wpa Supplicant from including the SSID in its scan requests, potentially reducing network overhead.

Another useful option is the bgscan parameter. This setting controls background scanning behavior. By default, Wpa Supplicant performs background scans to maintain a list of available networks. You can adjust the frequency of these scans or disable them altogether. To disable background scanning, add the line `bgscan=