ELEC S212 Network Programming And Design (Free Courseware)

Introduction to wireless networks

This module will enable you to understand various wireless technologies, especially those that have been infused into our daily lives. Also, a range of wireless network protocols and wireless LAN design models will be discussed. Another topic that we cannot afford to miss is wireless network security, because wireless medium is more vulnerable to attack than physical medium. In addition, some labs on wireless technology, with reference to the textbook A Practical Approach to Internet Programming and Multimedia Technologies (Kwan, R, Tsang, P, Kwok, P, Koong, K, Mak, J and Wu, J (2009) A Practical Approach to Internet Programming and Multimedia Technologies, Hong Kong: Open University of Hong Kong Press.), have been incorporated into the module to help you consolidate what you have learned.

Comparison of wireless and wired networks

The most obvious advantage of wireless networking is mobility, and wireless networks typically have a great deal of flexibility.

Mobility of wireless networking

Wireless network users can connect to existing networks and are then allowed to roam freely. Wireless data networks free users from the tethers of an Ethernet cable at a desk. They can work in the library, in a conference room, in the airport, or even in the coffee house across the street. As long as the wireless users remain within the range of the base station, they can take advantage of the network.

Flexibility of wireless networking

The flexibility of wireless networks can translate into rapid deployment. Wireless networks use a number of base stations to connect users to an existing network. With the infrastructure built, adding a user to a wireless network is a matter of configuring the infrastructure, but it does not involve running cables, punching down terminals, and patching in a new jack as wired networks need to. Only could such flexibility make possible the public hot spot operation, through which public users can gain access to the network connections wirelessly provided by service providers in various locations or premises.

Speed constrain of wireless networks

Information theory can be used to deduce the upper limit on the speed of a network. Wireless-network hardware tends to be slower than wired hardware. Unlike the 10-GB Ethernet standard, wirelessnetwork standards must carefully validate received frames (A term for the unit of data transferred on a network; its size depends on the type of network implemented. See the Glossary at the end of this module for more information.) to guard against loss due to the unreliability of the wireless medium.

Security issues of wireless networks

On wireless networks, security is often a critical concern because the network transmissions are available to anyone within range of the transmitter with the appropriate antenna. On a wired network, the signals stay in the wires and can be protected by strong physical-access control (locks on the doors of wiring closets, and so on). On a wireless network, sniffing is much easier because the radio transmissions are designed to be processed by any receiver within range.