Last week, a friend in the low-voltage industry asked us on the WeChat public account of the low-voltage industry network, “What exactly does WiFi mean? I use it every day but don’t know its origin. As someone working in the low-voltage industry, he felt very insecure about this.”
After using it for so many years, do you know what WiFi really means? Where did WiFi come from? Is there a story behind it? Let’s find out together!
WiFi is a type of wireless networking technology (commonly known as wireless broadband). Nowadays, mobile devices (laptops, tablets, smartphones, MP4 players) can basically receive WiFi signals, and connecting to WiFi is completely free. WiFi is generally divided into public and private use. Major cities now widely provide WiFi signals; as long as you turn on the WiFi receiver, it will automatically scan for nearby WiFi. Public WiFi has a wider range and can be connected without a password, while private WiFi is usually encrypted. Nowadays, households installing internet cables often use WiFi routers (advantages: completely free from wired connections; one cable can provide internet access for all wireless devices in the house; any mobile device with WiFi reception can use it; the signal can cover the entire house; supports multiple devices connecting simultaneously; supports fiber speed transmission). Now, high-end smartphones can also act as WiFi hotspots (similar to WiFi routers, emitting WiFi signals using SIM card data; using mobile data > WiFi reception data; avoid using hotspots without data as it can be very expensive).
In 1997, the IEEE (Institute of Electrical and Electronics Engineers) defined the initial standard for wireless local area networks (WLAN) technology, 802.11. In 1999, two supplementary versions were added: 802.11a (5GHz band, data transmission rate of 54Mbit/s) and 802.11b (2.4GHz band, data transmission rate up to 11Mbit/s).
However, the IEEE is only responsible for developing and publishing these standards and does not test the compliance of devices. The nonprofit Wi-Fi Alliance was established to fill this gap—establishing and enforcing standards. The alliance is dedicated to addressing the production and device compatibility issues of products compliant with the 802.11 standard, developing globally applicable specifications, and conducting rigorous compatibility testing on wireless devices. At the same time, Wi-Fi is also a trademark of the Wi-Fi Alliance, which certifies and authorizes products that pass the tests. From this perspective, Wi-Fi is merely a certification, similar to the QS mark on food packaging or the blue quarantine stamp on pork in the market.
It is worth noting that not every product compliant with IEEE 802.11 applies for Wi-Fi Alliance certification. Conversely, products lacking Wi-Fi certification do not necessarily mean they are incompatible with Wi-Fi devices.
In the realm of wireless local area networks, Wi-Fi refers not only to “wireless compatibility certification” but also to a type of wireless networking technology. Wi-Fi is a mainstream technical standard for WLAN access, such as IEEE 802.11a/b/g, which all belong to the Wi-Fi standard.
Wi-Fi Technology Interlude
The core technical standards for Wi-Fi (802.11a and 802.11g) were chosen and recognized by the IEEE and partially adopted from a wireless technology patent invented by the CSIRO (Commonwealth Scientific and Industrial Research Organisation) in Australia during the 1990s, which was successfully applied for in the United States in 1996 (US Patent Number 5,487,069).
In 2003, the IEEE requested the Australian government to waive its Wi-Fi patent so that the world could use Wi-Fi technology for free, but the request was denied.
Subsequently, CSIRO took a series of legal actions in the United States to force over 100 American companies, including Microsoft, Apple, and Dell, to pay patent usage fees. By the end of 2013, CSIRO’s wireless network patent would expire, but CSIRO had already won back $430 million in patent fees for the Australian government and itself.
“Domestic Version of Wi-Fi” China’s Own Wireless Standard—WAPI
WAPI (WLAN Authentication and Privacy Infrastructure) is a wireless local area network (WLAN) transmission protocol and security standard independently developed by China, with independent intellectual property rights. Similar to Wi-Fi, it operates within the same technical domain as the 802.11 transmission protocol. Unlike Wi-Fi’s unidirectional encryption authentication and lower security, WAPI employs mutual authentication to ensure transmission security.
However, due to political issues and doubts over compatibility, WAPI faced commercial blockades from the Wi-Fi Alliance. In March 2006, the ISO approved the 802.11i encryption standard and rejected China’s WAPI proposal. In June 2009, China resubmitted the WAPI standard application, during which WAPI’s infrastructure certification was approved by the ISO. To accelerate the industrial maturity of WAPI and under market pressure, China also negotiated with the IEEE that year, adopting a “support WAPI-compatible Wi-Fi” approach to promote WAPI, effectively lifting the ban on Wi-Fi. Many people may not remember that for security reasons, domestically sold mobile phones were not allowed to load Wi-Fi modules. At that time, the iPhone 3G and 3GS introduced by China Unicom also had their Wi-Fi functionality blocked, commonly referred to as the “castrated version”.
In fact, the only difference between WAPI and Wi-Fi is in the authentication and confidentiality aspects. Due to the similar hardware architecture of WAPI and Wi-Fi, wireless devices can support both Wi-Fi and WAPI standards simultaneously; all that is needed is to add WAPI certification on the software side. The exposure of the Snowden security incident has also made China pay more attention to WAPI, but due to WAPI’s bidirectionality, wireless routers must also emit signals according to the WAPI protocol; otherwise, in a wireless network environment, mobile terminals will still operate under the Wi-Fi protocol (common Wi-Fi security protocols include WEP, WPA/WPA2, WPA-PSK/WPA2-PSK), making WAPI often a mere decoration.
The Development of Wi-Fi Technology
Wi-Fi can be divided into five generations according to its development. Due to the widespread use of the 2.4GHz band in the ISM band, such as microwaves and Bluetooth, which can interfere with Wi-Fi and slow down its speed, the interference at 5GHz is relatively low. Dual-band routers can use both 2.4GHz and 5GHz, but devices can only use one band. It is generally recommended to connect to the 5GHz band (this requires device support; otherwise, only the 2.4GHz Wi-Fi band can be searched).
The first generation 802.11, established in 1997, used only 2.4GHz, with a maximum speed of 2Mbit/s.
The second generation 802.11b, used only 2.4GHz, with a maximum speed of 11Mbit/s, is gradually being phased out.
The third generation 802.11g/a, using 2.4GHz and 5GHz respectively, with a maximum speed of 54Mbit/s.
The fourth generation 802.11n, which can use either 2.4GHz or 5GHz, with maximum speeds of 72 and 150Mbit/s at 20 and 40MHz channel widths.
The fifth generation 802.11ac, which uses only 5GHz.
Wi-Fi Security Guide
1. Change the encryption protocol. Currently, “sniffing” tools can crack WEP and WPA encrypted wireless networks; WPA2 mode is relatively difficult to crack, so users need to upgrade their wireless network passwords and use WPA2 encryption mode.
2. Modify the router login name and password. It is recommended not to use common names like admin, guest, password, etc.
3. Disable SSID. Every wireless network has a name, which is the SSID. When we search for wireless networks, we find networks that have SSID enabled. If this feature is disabled, it won’t be found by “sniffing” tools. Of course, if the user wants to use the wireless network, they just need to add their own wireless network SSID and password in the “wireless network connection” properties.
4. Bind MAC addresses. Most wireless routers sold today have MAC address management functions. There are usually two modes: blacklist and whitelist. In whitelist mode, we only need to enter the MAC addresses of wireless terminals, such as laptops, that are allowed to access this network. This way, computers not in this allowed range cannot connect to our wireless network. In blacklist mode, we only need to enter the MAC addresses of users who have already invaded.
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