What is a Wireless Local Area Network (WLAN)?

A Wireless Local Area Network (WLAN) is a type of computer network that enables devices to communicate and exchange data with each other and access the internet without the need for physical cables. It relies on wireless technology, typically using radio waves, to establish connections between devices within a limited geographic area, such as a home, office, or campus. WLANs provide the convenience of wireless connectivity, allowing devices like laptops, smartphones, and tablets to connect and communicate with each other and with network resources. 

Dissecting Wireless Local Area Network (WLAN)

The concept of wireless communication, dating back to the late 19th century, involved pioneering work by individuals such as Nikola Tesla and Guglielmo Marconi in radio communication. However, it was in the 1970s and 1980s that researchers began experimenting with wireless data communication. In 1997, the Institute of Electrical and Electronics Engineers (IEEE) introduced the first IEEE 802.11 standard, specifying the foundation for WLANs. Additionally, the term "Wi-Fi" was coined in 1999 by the Wi-Fi Alliance to promote device interoperability within WLANs.

WLANs were initially developed to eliminate the need for physical cables and provide wireless connectivity in local areas, enhancing device mobility. This innovation aimed to offer a convenient alternative for connecting computers, printers, and various devices within homes, offices, and campuses.

WLANs Key Components

Wireless Local Area Networks (WLANs) consist of several key components that work together to enable wireless communication within a local area. These components include:

• Wireless Clients: Wireless clients are the devices that connect to the WLAN, such as laptops, smartphones, tablets, and IoT devices. They communicate with the WLAN through wireless network adapters.

• Access Points (APs): Access points are central devices in WLANs that bridge the wireless and wired networks. They serve as connection points for wireless clients, allowing them to access the network. APs transmit and receive data wirelessly and are often connected to the local wired network.

• Wireless Network Adapters: Wireless network adapters are hardware components or integrated circuits in devices that enable them to connect to and communicate over WLANs. These adapters can be built-in (e.g., in laptops) or external (e.g., USB Wi-Fi dongles).

• Wireless Router: A wireless router combines the functionality of a traditional wired router with wireless access capabilities. It often includes a built-in access point and provides routing, DHCP (Dynamic Host Configuration Protocol), NAT (Network Address Translation), and firewall functions.

• SSID (Service Set Identifier): The SSID is a unique name that identifies a WLAN. It allows wireless clients to identify and connect to a specific WLAN. Multiple SSIDs can be configured on a single access point or router to create multiple wireless networks.

• Wireless Security Mechanisms: WLANs employ various security mechanisms to protect data transmitted over the network. These include encryption protocols (e.g., WPA2/WPA3), authentication methods (e.g., WPA-Enterprise using a RADIUS server), and security settings (e.g., WEP, WPA).

• Wireless Channels: Wireless communication occurs on specific radio frequency channels within the 2.4 GHz and 5 GHz bands. The selection of channels and their allocation is crucial for minimizing interference and optimizing network performance.

• Wireless Standards (e.g., IEEE 802.11): WLANs adhere to specific wireless communication standards defined by organizations like the Institute of Electrical and Electronics Engineers (IEEE). These standards, such as IEEE 802.11a/b/g/n/ac/ax, dictate the protocols, data rates, and compatibility of WLAN devices.

• Centralized Management System: In larger WLAN deployments, centralized management systems or controllers may be used. These systems provide a centralized interface for configuring, monitoring, and managing multiple access points in an enterprise or campus environment.

• Antennas: Antennas are used to transmit and receive wireless signals. Access points and wireless routers are equipped with internal or external antennas that influence signal strength, coverage, and directionality.

• Backhaul Connection: The backhaul connection refers to the link between an access point and the wired network infrastructure. It can be a wired Ethernet connection or, in some cases, a wireless backhaul link for mesh networks.

• Power Sources: Access points and wireless routers require power sources. They can be powered through standard electrical outlets or, in some cases, through Power over Ethernet (PoE) for added flexibility in installation.

How WLAN works

For a WLAN to function, it must enable wireless devices to connect to access points, which serve as gateways to the wired network infrastructure. Data is transmitted as radio waves over the airwaves, and devices communicate through a set of standardized protocols and processes.

1. Initiating Data Transmission: The process begins when a device, such as a laptop or smartphone, requires wireless data exchange within a local area. In this step, the device's wireless network adapter converts data into radio frequency signals, preparing it for wireless transmission.

2. Connecting to an Access Point (AP): Devices search for available wireless networks by scanning for Service Set Identifiers (SSIDs). When they identify a matching WLAN, they send a connection request. The AP, acting as the gateway to the WLAN and connected to the wired network infrastructure, receives and processes this request.

3. Authentication and Association: Following the connection request, a critical phase involves authentication and association. Devices and the AP engage in a trust-establishing process. This typically involves exchanging security credentials (such as a Wi-Fi password) and verifying the device's identity. Upon successful authentication and association, the device is considered part of the WLAN and is assigned an IP address.

4. Data Transmission and Wireless Propagation: When data transmission is required, the device breaks the data into packets—small data units. These packets are then sent to the AP, which encapsulates them for wireless transmission. The AP utilizes its wireless antennas to transmit encapsulated data packets as radio waves over the air. These radio waves modulate onto specific frequency channels, usually within the 2.4 GHz or 5 GHz bands. On the other end, the device's wireless network adapter receives these radio signals, demodulates them, and extracts the data packets.

5. Data Routing and Response Handling: Upon reception, the received data packets are forwarded to the device's network stack, where they undergo processing and are routed to their intended destinations. This could involve routing to another device within the same WLAN or forwarding to a remote server on the internet. If the data transmission necessitates a response, the recipient device follows a similar process to send its response back to the originating device. The AP receives this response and transmits it wirelessly, while the original device processes the incoming data.

6. Data Reception and Error Handling: The device's wireless network adapter plays a crucial role in receiving incoming data, demodulating it, and passing it to the device's network stack for further processing. To ensure data integrity during transmission, WLANs incorporate error-checking mechanisms. In cases where data packets are received with errors, they may be requested for retransmission.

7. Continuous Communication and Disconnecting: As long as the device remains connected to the WLAN, this process of data transmission, reception, and communication persists. When a device no longer requires WLAN connectivity, it can initiate a disconnect request. In response, the AP terminates the association, releasing the device's allocated IP address.