Chapter 1 Intro to Wireless LAN's

Which one of the following IEEE 802.11 standards for wireless LAN's utilizes the 5 GHz UNII bands for its radio signal transmissions? A. 802.11b B. Bluetooth C. 802.11 D. 802.11g E. 802.11a

E The IEEE 802.11, 802.11b, 802.11g, Bluetooth, and HomeRF all use the 2.4GHz ISM bands, wheras the 802.11a standard uses the 5 GHz UNII bands

Which one of the following does a wireless LAN provide that a wired network does not? A. Mobility B. Centralized Security C. Reliability D. VPN Security

A The most alluring feature of a wireless network is the freedom to move about while remaining connected to the network. Wired networks cannot offer this feature.

Why would a mobile office be a good choice for using a wireless LAN? Choose all that apply. A. Wireless LAN's take less time to install than wired LAN's B. Wireless LAN equipment could be easily removed if the office moves C. Wireless LAN's do not require administration D. Wireless LAN's take a more centralized approach over wired LAN's

A, B In the setup and tear-down of a mobile office, cabling is the most significant task. In a small office, many of the common problems of a wireless network are not experienced so time-consuming tasks such as site surveys are not required. Centralized connection points (called access points) are minimal so wiring is minimal.

Why is a wireless LAN a good choice for extending a network? Choose all that apply. A. Reduces the cost of cables required for installation B. Can be installed faster than a wired network C. Hardware is considerably less expensive than wired LAN hardware D. Eliminates a significant portion of the labor charges for installation

A, B, D Cabling a facility is a time consuming and expensive task. Wireless networks can quickly and inexpensively be installed and configured.

Wireless ISP's provide which one of the following services? A. Small office / home office services B. Connectivity for large enterprises C. Last mile data delivery D. Building-to-building connectivity

C Wireless internet service providers (WISP's) provide last mile data delivery service to homes and businesses. In this fashion, they compete directly against wired ISP's such as telephone and cable companies.

Which one of the following is the IEEE family of standards for wireless LAN's? A. 802.3 B. 803.5 C. 802.11 D. 802.1x

C The 802.11 family of standards specifically address wireless LAN's. There are many flavors of standards addressing many types of wireless technologies and various topics related to wireless technologies.

A WISP would take advantage of which one of the following applications for wireless LAN's? A. Last mile data delivery B. Building-to-building bridging C. Classroom connectivity D. Home network connectivity

A WISP's are direct competitors for telephone companies and cable companies in providing last mile connectivity to businesses and residences in the broadband Internet services market.

Which one of the following is the most recently approved IEEE standard for wireless LAN's? A. 802.11a B. 802.11b C. 802.11c D. 802.11g

A The first wireless LAN standard was the 802.11 standard using the 2.4 GHz ISM band, approved in 1997. Following 802.11 was 802.11b raising the top speed to 11 Mbps and limiting use to DSSS technology only. Following 802.11b was 802.11a, which uses the 5 GHz UNII bands. The 802.11g standard is in draft form, and has not yet been completed.

Wireless LANs are primarily deployed in which one of the following roles? A. Backbone B. Access C. Application D. Core

B The access layer of the industry standard design model is where users attach to the network. Wireless network devices are most generally installed in this capacity. There are times when wireless networks may be used in a distribution role, such as building-to-building bridging, but a very large percentage of wireless networks are used strictly for access.

Who makes the regulations that govern the technical requirements, licensing, and usage of wireless LAN's in the United States? A. IEEE B. The Wi-Fi Alliance C. FCC D. ETSI

C The Federal Communications Commission (FCC) makes the laws regarding frequency band usage (licensed and unlicensed) in the United States. The IEEE makes the standards regarding wireless LAN's, which use RF frequencies. The Wi-Fi Alliance makes the hardware compatibility standard called Wi-Fi, and ETSI publishes communications standards for Europe.

Which one of the following IEEE standards for wireless LAN's is not compatible with the standard currently known as Wi-Fi? A. 802.11 B. 802.11g C. 802.11a D. 802.11b

C Wi-Fi is the hardware compatibility standard created and maintained by the Wi-Fi Alliance for 802.11b devices. IEEE 802.11g devices use the 2.4 GHz ISM band and are backwards compatible with 802.11b. 802.11a devices use a different set of frequencies and a different modulation type from 802.11b, and are thus incompatible.

As a consultant, you have taken a job creating a wireless LAN for an office complex that will connect 5 buildings in close vicinity together. Given only this information, which one of the following wireless LAN implementations would be most appropriate for this scenario? A. Last mile data service from a WISP B. Point-to-point bridge links between all buildings C. Point-to-multipoint bridge link from a central building to all remote buildings D. One central antenna at the main building only

C Since using a single antenna would likely have severe problems with coverage and many point-to-point bridge links (forming a partial or full mesh) would be highly expensive, the only logical alternative is to use point-to-multipoint bridge connectivity between buildings. This is an economically sound and highly effective solution.

Which one of the following are challenges that WISP's face that telephone companies and cable companies do not? Choose all that apply. A. Customers located more than 18,000 feet (5.7 km) from a central office B. High cost of installing telephone lines or copper cabling C. Trees as line of sight obstructions D. Rooftop access for antenna installation

C, D Wireless internet service providers (WISP's) face problems with line of sight limitations of 2.4 GHz wireless LAN systems. Antennas must be installed on rooftops or higher if possible in most cases. Trees and hills both pose problems to WISP's for the same reason.

Which one of the following would not be an appropriate use of a wireless LAN? A. Connecting two buildings together that are on the opposite sides of the street B. Connecting two computers together in a small office so they can share a printer C. Connecting a remote home to a WISP for internet access D. Connecting two rack mounted computers together

D Generally speaking, computers that are rack mounted together are servers, and servers should be connected to a high speed, wired backbone. Wireless networks are meant for mobile access rather than server room connectivity.

In what organization did the use of spread spectrum wireless data transfer originate? A. The Wi-Fi Alliance B. WLANA C. FCC D. U.S. Military

D During WWII, actress Hedy Lamarr and composer George Antheil co-invented the frequency hopping communications technique. The U.S. military began using frequency hopping spread spectrum communications in 1957 well before the broad commercial use that spread spectrum systems enjoy today.