What Is a Wireless Network or Wi-Fi?
A wireless network refers to a computer network that makes use of Radio Frequency (RF) connections between nodes in the network. Wireless networks are a popular solution for homes, businesses, and telecommunications networks.
It is common for people to wonder “what is a wireless network” because while they exist nearly everywhere people live and work, how they work is often a mystery. Similarly, people often assume that all wireless is Wi-Fi, and many would be surprised to discover that the two are not synonymous. Both use RF, but there are many different types of wireless networks across a range of technologies (Bluetooth, ZigBee, LTE, 5G), while Wi-Fi is specific to the wireless protocol defined by the Institute of Electrical and Electronic Engineers (IEEE) in the 802.11 specification and it’s amendments.
Wired vs. Wireless Network: What Is the Difference?
At the most obvious, a wireless network keeps devices connected to a network while still allowing them the freedom to move about, unencumbered by wires. A wired network, on the other hand, makes use of cables that connect devices to the network. These devices are often desktop or laptop computers but can also include scanners and point-of-sale machines.
There are more subtle technology differences that come in to play between wired and wireless. Most modern wired networks are now “full duplex”, meaning that they can be transmitting/receiving packets in both directions simultaneously. In addition, most wired networks have a dedicated cable that runs to each end user device.
In a Wi-Fi network, the medium (the radio frequency being used for the network) is a shared resource, not just for the users of the network, but often for other technologies as well (Wi-Fi operates in what are called ‘shared’ bands, where many different electronic devices are approved to operate). This has several implications: 1) unlike a wired network, wireless can’t both talk and listen at the same time, it is “half duplex” 2) All users are sharing the same space must take turns to talk 3) everyone can ‘hear’ all traffic going on. This has forced Wi-Fi networks to implement various security measures over the years to protect the confidentiality of information passed wirelessly.
Types of Wireless Connections
In addition to a LAN, there are a few other types of common wireless networks: personal-area network (PAN), metropolitan-area network (MAN), and wide-area network (WAN).
A local-area network is a computer network that exists at a single site, such as an office building. It can be used to connect a variety of components, such as computers, printers, and data storage devices. LANs consist of components like switches, access points, routers, firewalls, and Ethernet cables to tie it all together. Wi-Fi is the most commonly known wireless LAN.
A personal-area network consists of a network centralized around the devices of a single person in a single location. A PAN could have computers, phones, video game consoles, or other peripheral devices. They are common inside homes and small office buildings. Bluetooth is the most commonly known wireless PAN.
A metropolitan-area network is a computer network that spans across a city, small geographical area, or business or college campus. One feature that differentiates a MAN from a LAN is its size. A LAN usually consists of a solitary building or area. A MAN can cover several square miles, depending on the needs of the organization.
Large companies, for example, may use a MAN if they have a spacious campus and need to manage key components, such as HVAC and electrical systems.
A wide-area network covers a very large area, like an entire city, state, or country. In fact, the internet is a WAN. Like the internet, a WAN can contain smaller networks, including LANs or MANs. Cellular services are the most commonly known wireless WANs.
The Components of a Wireless Network
Several components make up a wireless network’s topology:
- Clients: What we tend to think of as the end user devices are typically called ‘clients’. As the reach of Wi-Fi has expanded, a variety of devices may be using Wi-Fi to connect the network, including phones, tablets, laptops, desktops, and more. This gives users the ability to move about the area without sacrificing their bridge to the network. In some instances, mobility within an office, warehouse, or other work area is necessary. For example, if employees have to use scanners to register packages due to be shipped, a wireless network provides the flexibility they need to freely move about the warehouse.
- Access Point (AP): An access point (AP) consists of a Wi-Fi that is advertising a network name (known as a Service Set Identifier, or SSID). Users who connect to this network will typically find their traffic bridged to a local-area network (LAN) wired network (like Ethernet) for communication to the larger network or even the internet.
How Does Wi-Fi Work?
A Wi-Fi based wireless network sends signals using radio waves (cellular phones and radios also transmit over radio waves, but at different frequencies and modulation).
In a typical Wi-Fi network, the AP (Access Point) will advertise the specific network that it offers connectivity to. This is called a Service Set Identifier (SSID) and it is what users see when they look at the list of available networks on their phone or laptops. The AP advertises this by way of transmissions called beacons. The beacon can be thought of as an announcement saying “Hello, I have a network here, if it’s the network you’re looking for, you can join”.
A client device receives the beacon transmitted by the AP and converts the RF signal into digital data, then that data is passed along to the device for interpretation. If the user wants to connect to the network, it can send messages to the AP trying to join and (when security is enabled) providing the proper credentials to prove they have the right to join. These processes are known as Association & Authentication. If either of these fail, the device will not successfully join the network and will be unable to further communicate with the AP.
Assuming all goes well, we come to the part that is the end user’s ultimate goal: passing data. Data from the client (or from the AP to the client) is converted from digital data into an RF modulated signal and transmitted over the air. When received, this is de-modulated, converted back to digital data, and then forwarded along to its destination (often the internet or a resource on the larger internal network).
Wi-Fi communication is only approved to transmit on specific frequencies, in most parts of the world these are the 2.4 GHz and 5 GHz frequency bands, although many countries are now adding 6GHz frequencies as well. These frequency bands are not the same that cellular networks use, so cell phones and Wi-Fi are not in competition for use of the same frequencies. However that does not mean that there are not other technologies that can operate in these bands. In the 2.4GHz band in particular there are many products, including Bluetooth, ZigBee, cordless keyboards, and A/V equipment just to name a small subset that does use the same frequencies and can cause interference.
Multiple Devices on One AP
If several Wi-Fi devices all want to connect to a network, they can all use the same AP. This offers a convenient solution, making Wi-Fi extensible into environments where coverage for many users is needed. Problems arise, however, if too many people need access at the same time, all needing high levels of bandwidth. For example, if several users are watching high-definition video at the same time, they may experience drops in performance because congestion at RF layer makes it difficult to impossible for the AP to pass all the necessary packets in a timely manner.
Wi-Fi Network Standards
The networking standard used by wireless architecture is IEEE 802.11. However, this standard is in continual development and new amendments come out regularly. Amendments to the standard are assigned letters, and while many amendments have been released, the most commonly known are:
This original amendment added support for the 5 GHz band, allowing transmission up to 54 megabits of data per second. The 802.11a standard makes use of orthogonal frequency-division multiplexing (OFDM). It splits the radio signal into sub-signals before they get to a receiver. 802.11a is an older standard and has been largely replaced by newer technology.
802.11b added faster rates in the 2.4GHz band to the original standard. It can pass up to 11 megabits of data in a second. It uses complementary code keying (CCK) modulation to achieve better speeds. 802.11b is an older standard and has been largely replaced by newer technology.
802.11g standardized the use of OFDM technology used in 802.11a in the 2.4GHz band. It was backwards compatible with both 802.11 and 802.11b. 802.11g is an older standard and has been largely replaced by newer technology.
Once the most popular standard 802.11n was the first time a unified specification covered both the 2.4GHz and 5GHz bands. This protocol offers better speed when compared to those that came before it by leveraging the idea of transmitting using multiple antennas simultaneously (usually called Multiple In Multiple Out or MIMO technology). 802.11n is an older standard, but some older devices may still be found in use.
802.11ac was only specified for the 5GHz band. It built upon the mechanisms introduced in 802.11n. While not as revolutionary as 802.11n was, it still extended speeds and capabilities in the 5GHz band. Most devices currently out in the wild are likely 802.11ac devices.
802.11ac technology was released in two main groups, usually called ‘waves’. The primary difference is that Wave 2 devices have a few more technical capabilities when compared to Wave 1, but it is all interoperable.
802.11ax (Wi-Fi 6)
802.11ax (much like 802.11n) unified the specification across all applicable frequency bands. In the name of simplicity, the industry has started to refer to it as Wi-Fi 6. Wi-Fi 6 has expanded the technologies used for modulation to include OFDMA, which allows a certain amount of parallelism to the transmission of packets within the system, making more efficient use of the available spectrum and improving the overall network throughput. Wi-Fi 6 is the latest technology and is what most new devices are shipping with.
Other 802.11 Standards
There are many more amendments that have been made to the standards over the years (most letters of the alphabet have been used over time). Additional 802.11 standards have focused on things like better security, increased Quality of Service, as well as many other enhancements.
Wi-Fi Connection Modes
There are multiple Wi-Fi network connection styles, the most prevalent are: infrastructure, ad hoc, and Wi-Fi Direct.
Infrastructure mode is the most common style of Wi-Fi, and it is the one people think of when they connect at home or the office. With infrastructure mode, you need an access point that serves as the primary connection device for clients. All other clients in the network (computer, printer, mobile phone, tablet, or other device) connect to an access point to gain access to a wider network.
Ad hoc mode is also referred to as peer-to-peer mode because it does not involve an access point, but is instead made up of multiple client devices. The devices, acting as “peers” within the network, connect to each other directly.
Wi-Fi Direct is a form of Ad Hoc, but with some additional features and capabilities. Wireless connectivity is provided to compatible devices that need to connect without the use of an access point. Televisions are frequently Wi-Fi Direct compatible, allowing users to send music or images straight from a mobile device to their TV.
The term “Wi-Fi hotspot” usually refers to wireless networks placed in public areas, like coffee shops, to allow people to connect to the internet without having to have special credentials. While some are free, others require a fee, particularly those administered by companies that specialize in the provision of hotspots in places like airports or bus terminals.
Many cell phones are hotspot-enabled, and users can turn on the feature by contacting their cell service provider. With a hotspot turned on, the user can share their internet connection with someone else, providing them with a password for more secure access.
How Fortinet Can Help
Wi-Fi management and security helps prevent unwanted users and data from harming devices connected to your network. With the Fortinet Wireless Access Points, you get a full view of the network and devices that are accessing it. It integrates with the Fortinet Security Fabric, allows for cloud access point management, and comes with a dedicated controller.
The FortiGate Integrated Wireless Management system gives you an enhanced security solution that incorporates fewer components, making it a simpler solution. As a next-generation firewall (NGFW), FortiGate provides full network visibility while automating protective measures and detecting and stopping more threats.