IEEE 802.11 Standard Wireless LAN

IEEE 802.11 Standard Wireless LAN

What Is Wireless Lan?

A wireless LAN is a wireless computer network that links two or more devices using wireless communication to form a local area network within a limited area such as a home, school, computer laboratory, campus, or office building.

According to another definition wireless, LANs are those Local Area Networks that use high-frequency radio waves instead of cables for connecting the devices in LAN.

Users connected by WLANs can move around within the area of network coverage.

Most WLANs are based upon the standard IEEE 802.11 or WiFi.

 

Requirements for a secure WLAN are as follows:

• A standard TCP/IP network environment.
• Active Directory, to store account properties and validate password-based credentials.
• Remote Authentication Dial-In User Service (RADIUS) support, to provide centralized connection authentication, authorization, and accounting.
• A certificate infrastructure, also known as public key infrastructure (PKI) for authenticating the user of a wireless client computer or Smartphones, etc.

 

IEEE 802.11 Architecture

The components of an IEEE 802.11 architecture are as follows

1) Stations (STA) − Stations comprise all devices and equipment that are connected to the wireless LAN.

A station can be of two types:

• Wireless Access Pointz (WAP) − WAPs or simply access points (AP) are generally wireless routers that form the base stations or access.
• Client. − Clients are workstations, computers, laptops, printers, smartphones, etc.

Each station has a wireless network interface controller.

2) Basic Service Set (BSS) −A basic service set is a group of stations communicating at the physical layer level. BSS can be of two categories depending upon the mode of operation:

• Infrastructure BSS − Here, the devices communicate with other devices through access points.
• Independent BSS − Here, the devices communicate in a peer-to-peer basis in an ad hoc manner.

3) Extended Service Set (ESS) − It is a set of all connected BSS.

4) Distribution System (DS) − It connects access points in ESS.

 

Advantages of WLANs

• Flexibility: Within radio coverage, nodes can communicate without further restriction.

Radio waves can penetrate walls, senders and receivers can be placed anywhere (also non-visible, e.g., within devices, in walls, etc.).

• Planning: Wireless ad-hoc networks allow for communication without previous planning, while wired network needs proper wiring plans.
• Design: Wireless networks allow for the design of independent, small devices which can for example be put into a pocket.

Cables not only restrict users but also designers of small notepads, PDAs, etc.

• Robustness: Wireless networks can handle disasters, e.g., earthquakes, floods, and natural calamities. whereas, networks requiring a wired infrastructure will usually break down completely in disasters.
• Cost: The cost of installing and maintaining a wireless LAN is on average lower than the cost of installing and maintaining a traditional wired LA due to the following reasons.-

1. After providing wireless access to the wireless network via an access point for the first user, adding additional users to a network will not increase the cost.
2. Wireless LAN eliminates the direct costs of cabling and the labor associated with installing and repairing it.

• Ease of Use: Wireless LAN is easy to use and the users need very little new information to take advantage of WLANs.
• They provide clutter-free homes, offices, and other networked places.
• The LANs are scalable in nature, i.e. devices may be added or removed from the network at greater ease than wired LANs.
• The system is portable within the network coverage and access to the network is not bounded by the length of the cables.
• Installation and setup are much easier than wired counterparts.
• The equipment and setup costs are reduced.

• Increased productivity for the mobile employee. The mobile user whose primary computer is a portable computer can change the location and always remain connected to the network.

This enables the mobile user to travel to various places let it be meeting rooms, hallways, lobbies, cafeterias, classrooms, and so forth.

 

Disadvantages of WLANs

• Since radio waves are used for communications, the signals are noisier with more interference from nearby systems.
• Greater care is needed for encrypting information. Also, they are more prone to errors. So, they require greater bandwidth than the wired LANs.
• WLANs are slower than wired LANs.