What is in This Video?
Nowadays, everyone is using wireless, so if it starts underperforming, you will probably get complaints. In this video, I will look at wireless configuration. If not configured correctly, this can cause performance problems.
I will have a look at signal strength, how to measure it, and what to do to fix it. Lastly, I will look at signal issues, which are problems that can affect your signal and how you can go about fixing them.
Wireless Configuration
To start checking your wireless configuration, the first thing to verify is the network name and SSID. If your Wi-Fi is slow, it may simply be that your device is connected to the wrong access point. If you are connected to a distant access point rather than a nearby one, your connection is going to be slow.
Wi-Fi can be quite stubborn when it comes to changing access points. So, if you connect to the coffee shop Wi-Fi and you happen to live quite close to it, your mobile device may keep trying to use the coffee shop Wi-Fi even though your home Wi-Fi has a stronger signal and is available.
Single SSID
It is possible to have multiple wireless access points that are using the same SSID and password. The way this is supposed to work is that as the user moves between the access points, the mobile device should change to the access point with the strongest signal. In reality, the mobile device can be quite stubborn when changing access points and will keep using the access point with the weaker signal even when a stronger signal is available.
If you are not getting good performance from the access point, check that your device is using the closest access point. Determining this can be a little tricky depending on the device you are using. This may require you to look at the MAC address of the access point the device is connected to, which can be tricky as, if the router has multiple bands, it will have multiple MAC addresses.
If this setup is not meeting your requirements, you may want to consider upgrading to use Mesh. Mesh uses proprietary technology to switch the mobile device between Wi-Fi devices. It does a better job than just using the standard Wi-Fi protocol; however, since it is proprietary, you will need to use Wi-Fi routers from the same manufacturer.
Protocol Used
If you are getting poor wireless performance, I would also check the protocol that is being used. To get more information from the access point, you may need to install additional software. In this case, I have installed the Android app WiFi Analyzer Open Source, which is a free Wi-Fi analyzer app.
In this example, the connection is using Wi-Fi version 6. There are seven different standards of Wi-Fi. Nowadays, they are called Wi-Fi followed by the version number; however, the very early versions were not using this convention and were later retrospectively adopted.
If your device is connected at a lower standard than it supports, it won’t perform as well as it could. You may need to change the configuration or upgrade your access point if it does not support the standard.
Legacy Devices
Legacy devices can also affect your wireless. Wi-Fi routers need to be running in compatibility mode in order to support older wireless standards. Enabling this mode means additional legacy packets are required to be sent, which increases overhead. Modern Wi-Fi routers have a lot of smarts in them and thus should be able to manage legacy devices fairly well.
Most of the older protocols have good collision avoidance with newer protocols, but they are not as efficient as the newer protocols and thus do have a performance impact on the network.
I say most because there is one protocol that does not play as well with the newer protocols. This is 802.11b. It is thus recommended that if you have these devices on the network, remove them. Although removing all legacy protocols will improve your network, 802.11b has poor collision avoidance. Having this on your network will cause more performance problems than the other protocols. The protocol did come out just over 20 years ago, so many devices no longer use it, and if they do, they may support other better protocols.
If you are having wireless performance problems and you think it is a device using 802.11b, I would just disable it on the router. This will prevent devices from using it, and if they support other protocols, they will connect using a different protocol because they have to. If the device only supports 802.11b, it is time to upgrade.
Network Speed
When looking at wireless troubleshooting, it is worth doing a speed test as well. You want to check network speed to confirm wireless is the problem. Your network problems could be something else, like congestion on the network, or perhaps the device you are connecting to is not sending the data back as quickly as it should be.
Keep in mind that speed tests may perform better than the network does normally due to a lot of different factors. If you want to get more accurate results, I would try changing the speed test server and running the test a number of times. You can also try downloading files from a website you know has good networking, for example, downloading a file from Microsoft.
Signal Strength
Next, I will look at signal strength. Signal strength is measured by the device itself. I will look into this more later in the video.
Wi-Fi signal strength is commonly measured in decibel-milliwatts or dBm, a unit that expresses power relative to one milliwatt. This logarithmic scale is used because it gives us a more human friendly way of looking at the result. While theoretical dBm can be positive to negative infinity, real world signals, due to regulation controls, never go into the positive and due to interference never reach values close to -100.
Shown here is the signal strength compared with the measurement. Higher dBm values (closer to zero) indicate strong, reliable signals, while lower values (more negative) represent weaker signals that can lead to performance issues. Signal strength under minus 50 is considered excellent. A signal strength of minus 70 is considered to be weak. Anything close to minus 100 dBm is generally considered unusable but it’s extremely uncommon to get a value that low. It is possible to get a value less than minus 100, but to make things simple, it is commonly assumed this is the lowest value. It is very unlikely to get anything under minus 100 under normal conditions and using standard equipment.
Received Signal Strength Indicator (RSSI)
I doubt that you will get a question on this in the exam, but it is covered in the official guide, so I will go through it. The Received Signal Strength Indicator or RSSI is a measure of the power of the signal received by the device. So the first question is, we have already looked at the measure of wireless signal, so how is this one different?
In the case of this wireless adapter, the RSSI value is reported. Depending on the wireless adapter, this value may or may not be available. For some wireless adapters, the RSSI value may only be accessible internally by the device.
To understand RSSI a bit better, let’s have a look at how it is calculated. Let’s consider that we have a Wi-Fi router that is transmitting a signal. The signal is received and measured by the device. This is the raw signal strength the wireless device has received.
The challenge with relying solely on raw signal strength measurements is that they do not account for a range of influencing factors such as the variations in signal processing capabilities across different hardware devices or the intrinsic hardware variations. These factors can significantly impact the perceived signal strength, making raw measurements less reliable for assessing true signal quality or network performance. Thus, you want to convert the raw signal measure into something that is more representative of the true signal strength.
What happens is the wireless device takes the raw measurement of the signal and calibrates it for the device, thus creating the RSSI value. In a moment, I will have a look at how the RSSI value is used by the wireless device.
The problem when looking at the signal strength of a wireless device is that unless stated otherwise, the device may report the power or RSSI value. You won’t know which. There is also no industry standard for the calculation of the RSSI value. Thus, the value is recommended to be used relatively rather than as an accurate value. Unless you know exactly how your device is calculating the value, you can’t assume anything, unfortunately. More on that later in the video. Before that, the big question to ask is why the device is calculating the RSSI value in the first place?
Rate Adaptation
The main use of the RSSI is for rate adaptation. Rate adaptation is when a wireless device automatically adjusts its data transfer rate to match the current network conditions to optimize performance.
A wireless device may reduce its transfer rate when the wireless signal is low. A slower data rate increases the reliability of data transfer. Different devices vary in how well they transfer data over weak signals. So you can understand why the RSSI value may vary in how it is calculated from device to device. So the next question is, if you have wireless devices that report the signal differently, which one would you use?
In The Real World
In the real world, focus on the relative measurements. If you take a measurement in one place and another in a different location, focus on the difference in the measurements. This will allow you to determine any areas of poor performance.
Professional Wi-Fi analyzers provide more accurate measurements, but it depends on your budget. Generally speaking, a decent wireless adapter in a laptop will get better results than a mobile device. At the end of the day, the hardware used for the wireless adapter will determine what result you will get. There are some high-end mobile devices which have very good wireless adapters.
Signal Issues
When trying to troubleshoot wireless issues, I often compare it to trying to have a conversation with someone in a crowded room. If someone is yelling nearby, it is hard to hear the person you are talking to. Similarly, interference from other devices using the same Wi-Fi frequency can disrupt your signal.
Obstacles like walls and furniture can weaken sound waves, making it difficult to hear someone in another room. Likewise, physical barriers like walls and furniture can weaken Wi-Fi signals.
The wireless device you are using is like your ears trying to pick up the signal from the access point. When it comes to wireless signals, they act a lot like sound waves.
When looking at signal issues, it is a good idea to measure the signal strength. Once you have the signal strength, you can set some kinds of expectations of what performance you may get. Signal strength under minus 60 is good for most activities. This will generally appear as an excellent or good connection. If you are transferring video files or need responsive networking, closer to zero is better, but greater than minus 60 is a good rule of thumb to use.
A signal between minus 60 to minus 70 is usable for basic tasks. This is good for activities like web surfing and using email. You probably will not get fast response times; however, for basic tasks, you don’t need fast response times. This will generally appear as a fair connection.
Wi-Fi connections in the minus 70 dBm to minus 80 dBm range fall into a limited functionality zone. While basic tasks like web browsing and email might work, expect slower speeds, increased buffering, and even occasional dropped connections. This performance can vary depending on the device itself. Devices have a minimum signal threshold for a connection. If the signal strength dips below this threshold, which can vary by device, it may not connect at all. These connections are generally reported as weak.
Any connection under minus 80 is considered unreliable. These connections are generally reported back as weak. If your device does connect, expect disconnects and other problems if it connects at all. If you find your connection often disconnects and reconnects, it is often due to poor signal.
Signal Degradation
There is also the problem of signal degradation. Wireless signals degrade as they travel through different materials. Some objects more than others. For example, objects made of metal, insulation, concrete, metal mesh, and mirrors block wireless signals.
All these objects cause the signal to degrade either by absorbing it or causing it to bounce in a different direction. This means your device will receive a reduced signal and have trouble communicating back to the access point.
To attempt to fix this, you can reposition the device. If you move the device to another location, you should be able to get a better signal. You can also adjust the antennas of the device or the access point. If the signal is bouncing off an object, changing the angle the signal is traveling may help. Lastly, you can add an extender to the network. For example, putting an extender on the side of the objects that are causing the signal degradation.
Channels and Bands
Wireless will use a particular channel and band. If you are having signal problems, it may be due to high congestion on the channel and perhaps the bandwidth. You may want to consider changing the wireless channel. In the old days, it was worth manually changing the channel to a channel with less traffic; however, nowadays many Wi-Fi routers have an auto setting which automatically changes the channel for you.
The 2.4 GHz band nowadays is quite congested. If you live in an apartment building, there will be many different Wi-Fi routers in use. Also, other devices use the 2.4 GHz range, so you may not have much luck trying to change channels, although you may get some improvements.
Higher bandwidth generally has less congestion. This comes down to two reasons. The higher bandwidths have less range and thus less overlapping networks. The other reason is the higher bandwidths are not used as much. So if you are having congestion problems, if changing the channel does not work, moving to a higher band may help.
Power Related Problems
I will next have a look at Wi-Fi power-related problems. Although the A+ exam has previously asked questions on this topic from the material provided, it seems less likely, but you never know.
One thing you may be able to do is increase the power of your Wi-Fi device. Keep in mind that the max level is determined by your country’s regulations. It is not uncommon for the Wi-Fi router to be configured to the max settings by default.
If you are able to increase the power, this will increase the range of the Wi-Fi. This will help reduce the size of the dead spots.
If you decrease the power of the Wi-Fi access point, this will decrease the range of the Wi-Fi. This helps prevent eavesdropping on the network. So, if you are worried that someone may park in your carpark and try to access your Wi-Fi, decreasing the power can help prevent them from accessing the network. However, reducing the power does not eliminate the need to have good security on the network.
Another reason you may want to decrease the power is that it also reduces the interference, which may reduce the congestion on the network. When you have a lot of Wi-Fi access points in the same area, reducing the power can sometimes help. Although modern Wi-Fi protocols are good at avoiding collisions.
End Screen
I hope this video has helped you troubleshoot your wireless and keep that mysterious guy in the van from tapping into your Wi-Fi. Until next time, thanks for watching.
References
“The Official CompTIA A+ Core Study Guide (Exam 220-1101)” pages 220 to 212
“WiFi Received Signal Strength Indicator (RSSI)” https://www.youtube.com/watch?v=j_cEmPJFftM
“Picture: WiFi logo” https://commons.wikimedia.org/wiki/File:WiFi_icon.svg
Credits
Trainer: Austin Mason http://ITFreeTraining.com
Voice Talent: HP Lewis http://hplewis.com
Quality Assurance: Brett Batson http://www.pbb-proofreading.uk
