Properties of Wireless Media
Wireless media carry electromagnetic signals that represent the binary digits of data communications using radio or microwave frequencies.
Wireless media provides the greatest mobility options of all media, and the number of wireless-enabled devices continues to increase. As network bandwidth options increase, wireless is quickly gaining in popularity in enterprise networks.
The figure highlights various wireless-related symbols.
Wireless does have some areas of concern, including:
• Coverage area: Wireless data communication technologies work well in open environments. However, certain construction materials used in buildings and structures, and the local terrain, will limit the effective coverage.
• Interference: Wireless is susceptible to interference and can be disrupted by such common devices as household cordless phones, some types of fluorescent lights, microwave ovens, and other wireless communications.
• Security: Wireless communication coverage requires no access to a physical strand of media. Therefore, devices and users, not authorized for access to the network, can gain access to the transmission. Network security is a major component of wireless network administration.
• Shared medium: WLANs operate in half-duplex, which means only one device can send or receive at a time. The wireless medium is shared amongst all wireless users. The more users needing to access the WLAN simultaneously, results in less bandwidth for each user. Half-duplex is discussed later in this chapter.
Although wireless is increasing in popularity for desktop connectivity, copper and fiber are the most popular physical layer media for network deployments.