About Wireless LAN.

Wireless LAN

WLANs are typically restricted in their diameter to buildings, a campus, single rooms etc. and are operated by individuals, not by large-scale network providers. The global goal of WLANs is to replace office cabling, to enable tetherless access to the internet and, to introduce a higher flexibility for ad-hoc communication in, e.g., group meetings.

Advantages of WLANs are: 

• Flexibilty: 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: Only wireless ad-hoc networks allow for communication without previous planning, any wired network needs wiring plans. As long as devices follow the same standard, they can communicate.
• Design: Wireless networks allow for the design of small, independent devices. Wireless senders and receivers can be hidden in historic buildings, i.e., current networking technology can be introduced without being visible.
• Robustness: Wireless networks can survive disasters, e.g., earthquakes. If the wireless device survive, people can still communicate. Networks requiring a wired infrastructure will usually break down completely.
• Cost: After providing wireless access to the infrastructure via an access point for the first user, adding additional users to a wireless network will not increase the cost. Wireless connections do not wear out.

WLANs have several disadvantages:

• Quality of service: WLANs typically offer lower quality than their wired conterparts. The main reasons for this are the lower bandwidth due to limitations in radio transmission, higher error rates due to interference, and higher delay/delay variation due to extensive error correction and detection mechanisms.
• Proprietary solutions: Due to slow standardization procedures, many companies have come up with proprietary solutions offering standardized functionality plus many enhanced features. However, these additional features only work in a homogeneous environment, i.e., when adapters from the same vendors are used for all wireless nodes. Atleast most components today adhere to the basic standards IEEE 802.11b or (newer) 802.11a.
• Restrictions: All wireless products have to comply with national regulations. Several government and non-government institutions worldwide regulate the operation and restrict frequencies to minimize interference. Consequently, it takes a very long time to establish global solutions which comprises many individual standards. WLANs are limited to low-power senders and certain license-free frequency bands, which are not the same worldwide.
• Safety and security: Using radio waves for data transmission might interfere with other high-tech equipment in, e.g., hospitals. Senders and receivers are operated by laymen and, radiation has to be low. Special precautions have to be taken to prevent safety hazards. The open radio interface makes eavesdropping much easier in WLANs than, e.g., in the case of fiber optics. All standards must offer(automatic) encryption, privacy mechanisms, support for anonymity etc. Otherwise more and more wireless networks will be hacked into as is the case already.