CWNA Guide to Wireless LAN's Second Edition - Chapter 1

CWNA Guide to Wireless LANs, Second Edition

Chapter OneIt’s a Wireless World

CWNA Guide to Wireless LANs, Second Edition 2

Objectives

• Describe how wireless technology is used in daily activities

• Tell how wireless local area networks are used in applications such as education, business, travel, construction, and other areas

• Explain the advantages and disadvantages of wireless technology


A Day in the Life of a Wireless User: Home

• Hotspots: Locations where wireless data services are available

• Wireless local area network (WLAN): Essentially identical to standard local area network (LAN) – Except devices not connected by wires– Can increase productivity


A Day in the Life of a Wireless User: Car

• Bluetooth wireless standard: Enables short range wireless communication– Used in many small devices


A Day in the Life of a Wireless User: Office

• Fixed broadband wireless: Wireless transmissions between immobile devices – Typically between office buildings– Utilizes small, customized antennas

• Free space optics (FSO): Alternative to high-speed fiber optic transmissions


A Day in the Life of a Wireless User: Field

• Handheld devices used to connect to nearest cell tower– Cell tower connects to local telephone company– Telephone company connects to appropriate

resources• Such as e-mail servers


A Day in the Life of a Wireless User: On Site

• Radio frequency identification (RFID) tags: – “Electronic barcodes”– Used to identify items– Can be read if anywhere within range of transmitted

radio signal• Depending on device


A Look at Wireless Technologies

• Wireless technology woven throughout many aspects of life

• Useful to get overview of some current technologies in today’s wireless world


Wireless Local Area Networks (WLANs)

• Wi-Fi (Wireless Fidelity): Based on standard that transmits at up to 11 Mbps

• Computers on WLAN must have wireless network interface cards (wireless NIC or Wireless adapter)– Performs same basic functions as standard NIC,

plus more

• Access point (AP): Transfers signals between wireless NICs

• Patch cable connects AP to wired LAN or Internet


Wireless Local Area Networks (continued)

Figure 1-3: Wireless LAN


Wireless Local Area Networks (continued)

Figure 1-4: Home wireless LAN


Bluetooth

• Low-power wireless data and voice transmission technology

• Bluetooth devices communicate via radio modules– Link manager: Software that helps identify other

Bluetooth devices, creates links between devices, and sends and receives data

• Transmit data at up to 1 Mbps over 10 meters

• Bluetooth devices within range of each other automatically connect– Master and slave


Bluetooth (continued)

• Piconet: Bluetooth network containing a master and at least one slave

Figure 1-5: Bluetooth device


Telecommunications Links

• Integrated Services Digital Networks (ISDN): Transmits at 256 Kbps

• T-1 lines: Transmit at 1.544 Mbps

• Cable modems: Use television cable connection

• Digital subscriber lines (DSL): Use telephone lines

• WiMax: Signal transmitted between antennas– Up to 75 Mbps and over up to 35 miles– Fixed Broadband


Telecommunications Links (continued)

• FSO: Transmit at speeds up to 1.25 Gbps over up to 4 miles– Line-of-site transmission

Figure 1-6: Free space optics transceiver


Telecommunications Links (continued)

Figure 1-7: Wireless office technologies


Cellular Telephony

• Global Systems for Mobile (GSM) communications technology: Coverage includes most of US and parts of Europe and Japan – Transmission speeds up to 9.6 Kbps– Information transmitted based on Wireless

Application Protocol (WAP)• Standard way to transmit, format, and display data for

devices like cell phones and handheld devices


Cellular Telephony (continued)

Figure 1-8: Browsing the World Wide Web


Cellular Telephony (continued)

• WAP cell phone runs a microbrowser that uses Wireless Markup Language (WML) instead of HTML

• WAP gateway or proxy: Translates between WML and HTML

Figure 1-9: WAP communications


Radio Frequency Identification (RFID)

• Like an electronic barcode:– Can contain larger amounts of updatable information– Information transmitted via radio waves– Range typically about 1 foot at 5 Mbps

Figure 1-10: RFID tag


Wireless Technology Categories

Table 1-1: Typical wireless technologies


Wireless LAN Applications: Education

• Educational institutions some of first adopters of WLANs – Dramatic advantages in teaching and learning

• Wireless LAN connections offer students important degree of freedom

• WLAN technology translates into cost savings for colleges– Reduces need for wiring and infrastructure– Fewer computer labs necessary


Wireless LAN Applications: Education (continued)

Figure 1-11: Campus access point locations


Wireless LAN Applications: Business

• Wireless LAN technologies have significantly changed how business conducted– Meetings not confined to conference rooms– Easier to connect to network resources and Internet– Can create office in space where traditional

infrastructure does not exist


Wireless LAN Applications: Travel

• Travel industry perhaps adopted wireless technologies more than any other industry– Many airport terminals provide wireless hotspots– Several large airlines providing wireless capabilities

to passengers during flights– Some airlines use WLAN technology to

communicate with aircraft on ground– Some airlines use WLAN technology to facilitate

maintenance tasks– Some airlines use new wireless data service to send

and receive messages


Wireless LAN Applications: Construction

• Wireless technology has greatly benefited construction industry– Better management of resources– Better management of paperwork

• Construction equipment being fitted with wireless terminals – “Smart” equipment– GPS information can provide location information to

within centimeters


Wireless LAN Applications: Warehouse Management

• New products arrive continuously – Must be inventoried and stored

• Products being shipped must first be located then transferred to correct location and truck– Mistakes in inventory or inability to locate items can

be devastating– Mark inventory with RFID tags

• Warehouse management system (WMS) software: Can manage all activities from receiving through shipping– Utilize wireless technology


Wireless LAN Applications: Public Safety

• Public safety departments using WLANs and GSM to communicate information with public safety vehicles– City-owned buildings equipped with APs– Large volumes of data can be quickly downloaded to

vehicles• e.g., building floor plans, photographs of criminal

suspects, and maps


Wireless LAN Applications: Healthcare

• Wireless LAN point-of-care computer systems allow medical staff to access and update patient records immediately– Document patient’s medication administration

immediately– Extensive use of RFID tags

• Identify healthcare professionals, patients, medications

– System verifies that medication being administered to correct patient in correct dosage

• Eliminates potential errors and documentation inefficiencies


Wireless LAN Applications: Healthcare (continued)

• Documentation process takes place at bedside where care delivered– Improves accuracy

• Hospital personnel have real-time access to latest medication and patient status information

• Wireless technology also used in other medical areas:– e.g., video pills


Wireless LAN Applications: Healthcare (continued)

Figure 1-12: Video pill


Wireless Advantages and Disadvantages: Advantages

• Mobility: Primary advantage of wireless technology– Enables individuals to use devices no matter where

users roam within range of network– Increasingly mobile workforce is characteristic of

today’s business world– WLANs give mobile workers freedom while allowing

them to access network resources– “Flatter” organizations: WLANs give team-based

workers ability to access network resources needed while collaborating in team environment



(continued)• Easier and Less Expensive Installation:

Installing network cabling in older buildings difficult and costly– Wireless LAN is ideal solution– Eliminating need for cabling results in cost savings

• Significant time savings as well

– Allows offices to reorganize easily

• Increased Reliability: Wireless LAN technology eliminates certain types of cable failures and increases overall network reliability



(continued)• Disaster Recovery: Documented disaster

recovery plan vital to every business– Hot site: Off-site facility that can run business’s

operations if primary site is not available• Generally maintained by third party• Expensive

– Cold site: Customer provides and installs equipment• Many businesses use cold sites and WLANs as major

piece of disaster recovery plan– No consideration given to network cabling


Wireless Advantages and Disadvantages: Disadvantages

• Security: Wireless signals broadcast in open air– Security for wireless LANs is prime concern

• Unauthorized users might access network

– War driving

• Attackers might view transmitted data

• Employees could install rogue access points

• Attackers could easily crack existing wireless security

– Older wireless products have very weak security features


Wireless Advantages and Disadvantages: Disadvantages

(continued)• Radio Signal Interference: Signals from other

devices can disrupt wireless transmissions– Or wireless device may be source of interference for

other devices– e.g., Microwave ovens, elevator motors,

photocopying machines, theft protection devices, cordless telephones

– Solution: Locate source of interference and remove• Health Risks: Wireless devices emit RF energy

– Not known if or to what extent low levels of RF might cause adverse health effects


Summary

• Wireless devices and technologies enable users to roam almost anywhere and remain connected to data and voice networks

• A WLAN, also known as Wi-Fi, functions the same as a standard wired network except devices send radio frequency signals through the air instead of being connected to the network by cabling

• Bluetooth devices communicate using small radio transceivers called radio modules that are built into microprocessor chips


Summary (continued)

• Two popular technologies are WiMax and free space optics (FSO)

• Handheld devices can send and receive wireless signals using the Global System for Mobile (GSM) communications technology

• RFID tags function as electronic barcodes• Wireless personal area networks (WPANs) cover

technologies where the transmission generally extends only a few meters or feet, whereas wireless local area networks (WLANs) are generally restricted to 112 meters (375 feet)


Summary (continued)

• Wireless LAN applications can be found in industries in which employees need the freedom to conduct business without being confined to a specific location

• Wireless LANs have significant advantages, including increased mobility, easier and less expensive network installations, increased network reliability, and disaster recovery

• Some of the disadvantages of wireless LANs include security, radio signal interference, and health concerns

Documents

CWNA Guide to Wireless LAN's Second Edition - Chapter 1