1.7. Specifying the Characteristics of Wireless Technologies

One of the newest and most exciting forms of communication is wireless communication. This type of communication is still in its infancy, and many competing standards exist. Wireless net-works, if properly installed, can add to the flexibility on your network. To properly install a wireless network you must be familiar with wireless networking standards. In this section, we discuss wireless networking standards and their effect on your network design.

1.7.1. Critical Information

You should know about the most common wireless standards used in today's networks. Specifically, you should be familiar with their carrier speed, frequency, transmission type, and topology. In this section, we discuss these characteristics in regard to each of the most common wireless technologies.

1.7.1.1. 802.11

802.11 is the IEEE specification created for wireless LAN technology. 802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients. The IEEE accepted the specification in 1997. The original 802.11 standard used a frequency hopping spread spectrum radio (FHSS) signal. There have been many revisions to the standard since then. The following are the major 802.11 standards in use today. 802.11x represents the family of standards that use the direct sequence spread spectrum (DSSS) radio signal. Table 1.10 compares the characteristics of 802.11 wireless technologies.

802.11a Uses orthogonal frequency division multiplexing to increase bandwidth. This standard uses the 5GHz radio band and can transmit at up to 54Mbps. It is not widely used today.

802.11b Uses DSSS in the 2.4GHz radio band. This standard can transmit at up to 11Mbps with fallback rates of 5.5Mbps, 2Mbps, and 1Mbps. It is one of the most commonly used standards today.

802.11g Uses DSSS and the 2.4GHz radio band. This standard enhances the 802.11b standard and can transmit at speeds up to 54Mbps.

1.7.2. Infrared

The term infrared means "below red." In other words, infrared communication is communication made possible by light that is below red in the color spectrum of light. Human beings cannot see this light, but we can build devices that can transmit and receive it. To make use of this light, a group of manufacturers known as the Infrared Data Association (IrDA) developed a standard in the late 1990s. Many manufacturers have adopted this standard for use with the devices that they manufacture. Because of this, many devices now have the distinctive infrared port that allows them to communicate with other devices without the use of wires. The biggest difference between infrared and other wireless technologies is that infrared requires "line of sight" communications between devices. Also, infrared does not work well in bright sunlight.

1.7.3. Bluetooth

Bluetooth is a short-range radio technology that was developed by Ericsson, IBM, Intel, Nokia, and Toshiba. Many products sold today use Bluetooth technology, including printers, mice, keyboards, scanners, and many more. All products must pass interoperability testing by the Bluetooth Special Interest Group prior to their release.

1.7.4. Exam Essentials

Be familiar with the main types of wireless networks. The main types of wireless networks are 802.11, Infrared, and Bluetooth. You should be familiar with the each of these types of net-works and where they might be used.

Know the main characteristics of the main types of wireless networks. You should know the main characteristics such as carrier speed, frequency, transmission type, and topology for the main types of wireless networks.

List the characteristics of 802.11x components. The 802.11x specification refers to the family of standards that use DSSS, usually on the 2.4GHz radio band. The most common of these are the 802.11b and 802.11g standards.

Know the characteristics of 802.11a. 802.11a is a standard for wireless communication that uses OFDM on the 5GHz radio band. 802.11a, which can communicate at a maximum rate of 54Mbps, is rarely used in today's networks.

Describe the characteristics of 802.11b. 802.11b is a standard for wireless communication that uses DSSS on the 2.4GHz radio band. 802.11b, which can communicate at a maximum rate of 11Mbps, is in common use in many networks today.

List the characteristics of 802.11g. 802.11g is a standard for wireless communication that uses DSSS on the 2.4GHz radio band. 802.11g, which can communicate at a maximum rate of 54Mbps, is in common use in many networks today.

Know the characteristics of infrared. The term infrared means "below red." Infrared light is light that humans cannot see, but we can use it to control devices and to communicate to them. The standards for the use of infrared light have been developed by the Infrared Data Association (IrDA). Infrared devices require a line-of-sight connection with a device in order to communicate effectively. Many devices are now including infrared capability.