Faculty of Computer Science & Engineering

FACULTY OF

COMPUTER SCIENCE & ENGINEERING

Chapter 01. Introduction to Wireless LANs

OBJECTIVES The Wireless LAN Market

History of Wireless LANs Today’s Wireless LAN Standards

Define the roles of the organizations-FCC (The Federal Communications Commission)

- IEEE

- Wi-Fi Alliance Identify some of the uses for spread spectrum

technologies - Wireless LANs, PANs, MANs, and WANs

OBJECTIVES

Applications of Wireless LANs Access Role Network Extension Building-to-Building Connectivityxtension Last Mile Data Delivery Mobility Small Office-Home Office

Advantages and Disadvantages of WLAN

THE WIRELESS LAN MARKET The market for wireless LANs seems to be

evolving in a similar fashion to the networking industry

The big difference between LAN and WLAN Wireless LANs allow so many flexibilities in their

implementation

History of Wireless LANs The military needed a simple, easily

implemented, and secure method of exchanging data in a combat environment.

Today’s Wireless LAN Standards Wireless LANs transmit using radio frequencies The Federal Communications Commission (FCC)

regulates the use of wireless LAN devices. Wireless LAN Standards are created and

maintained by the Institute of Electrical

andElectronic Engineers (IEEE).

Following wireless LAN standards: 802.11, 802.11a, 802.11b, 802.11b+ 802.11g, 802.11h

TODAY’S WIRELESS LAN STANDARDS

IEEE 802.11 was born 1997 Standard beginning of WLAN Use in both Spread Spectrum Technology

FHSS and DSSS Bandwith max is 2 Mbps Frequency band 2,4 Ghz ISM

TODAY’S WIRELESS LAN STANDARDS

IEEE 802.11 a Open of 802.11 standard Provides data rates up to 54 Mbps

Frequency band 5 Ghz UNII Use tecnology Orthogonal Frequency Division

Multiplexing ( OFDM ). Non-overlapping 8 channel

TODAY’S WIRELESS LAN STANDARDS IEEE 802.11 b Open of 802.11 standard Uses high-rate direct-sequence spread spectrum (HR/DSSS)

instead of the original DSSS.

Provides data rates up to 11 Mbps

Frequency band 2,4 Ghz ISM Non-overlapping 3 channel IEEE 802.11 b+ Provides data rates up to 22 Mbps

TODAY’S WIRELESS LAN STANDARDS

IEEE 802.11 g Open of 802.11b standard Use tecnology Orthogonal Frequency Division

Multiplexing ( OFDM ). & DSSS Provides data rates up to 11 Mbps 54 Mbps

Frequency band 2,4 Ghz ISM

TODAY’S WIRELESS LAN STANDARDS

ROLES ORGANIZATIONS PLAYWITHIN THE WLAN INDUSTRY

There are three primary categories of organizations that guide

the wireless industry. These categories include regulation,

standardization, and compatibility

The Federal Communications Commission (FCC) is an

example of regulatory bodies.

The Institute of Electrical and Electronics Engineers (IEEE) is

an example of a standards development organization

The Wi-Fi Alliance is a compatibility testing and certification

group

FCC (THE FEDERAL COMMUNICATIONS COMMISSION

WLAN devices use radio wave communications, they

fall under the regulatory control of the FCC.

The factors regulated by the FCC include:

■ Radio frequencies available

■ Output power levels

■ Indoor and outdoor usage

FCC (THE FEDERAL COMMUNICATIONS COMMISSION

The FCC regulates which frequencies may be used

within the regulatory domain it manages

The FCC provides two types of license-free bands for

radio communications: the Industrial Scientific Medical

(ISM) bands and the Unlicensed National Information

Infrastructure (U-NII) bands.

2.4 GHz ISM, U-NII bands exist in the 5 GHz frequency

range . They are all used by IEEE 802.11

IEEE

The Institute of Electrical and Electronics Engineers

The IEEE developed standards that impact and benefit

wireless networking.

These standards include wireless specific standards as

well as standards that have been implemented in the

wired networking domain, which are now being utilized

in the wireless networking domain.

IEEE

WI-FI ALLIANCE

The Wi-Fi Alliance is a certification organization that provides testing and interoperability analysis for the wireless industry.

While the FCC makes the rules and the IEEE determines how to live within those rules, the Wi-Fi Alliance ensures that devices are compatible with the IEEE’s way of implementing WLAN technology.

Only products of Alliance members that have been tested successfully by the Wi-Fi Alliance are actually allowed to claim that they are Wi-Fi Certified.

SPREAD SPECTRUM TECHNOLOGY USES

Spread spectrum technology is used in multiple ways that can be organized within four primary categories: wireless LANs, wireless PANs (WPANs), wireless MANs (WMANs) and wireless WANs.

WIRELESS LANS

Activities in Circle 200 m

There are three primary roles that wireless LANs play in today’s enterprise organizations: Access role

Distribution role

Core role

WIRELESS PANS A wireless PAN (personal area network)

provides hands-free connectivity and communications within a confined range and limited throughput capacity.

Bluetooth is a perfect example of a wireless PAN technology that is both beneficial and in widespread use.

Operating in the 2.4 GHz ISM band, Bluetooth technologies can cause interference with wireless LAN technologies like DSSS, HR/DSSS, and ERP.

WIRELESS MANS

WiMAX is the most commonly referenced wireless MAN technology

WiMAX is based on the IEEE 802.16 standard and provides expected throughput of approximately 40 Mbps for fixed, line of sight connections and approximately 15 Mbps for mobile, non–line of sight connections

WIRELESS MANS

Was born in October, 2001 Operating in the 2- 66 GHz band Operating in the 2-11 Ghz at Europe Operating in the 3.5 Ghz for Mobie Operating in the 10-66 for Fixed points

WIRELESS WANS What is the WAN ?

WIRELESS WANS

WIRELESS WANS WAN services ?

WIRELESS WANS

Integrated Services Digital Network Packet-Switched

Frame Relay Cell –Switched

Switch ATM

WLAN,WPAN,WMAN,WWAN

APPLICATIONS OF WIRELESS LANS Access Role Network Extension Building-to-Building Connectivityxtension Last Mile Data Delivery Mobility Small Office-Home Office

Applications of Wireless LANs Corporate Data Access and End-User Mobility

APPLICATIONS OF WIRELESS LANS Network Extension

APPLICATIONS OF WIRELESS LANS Building-to-Building Connectivity: Bridging

APPLICATIONS OF WIRELESS LANS Last-Mile Data Delivery: Wireless ISP

APPLICATIONS OF WIRELESS LANS Small Office/Home Office (SOHO) Use

APPLICATIONS OF WIRELESS LANS Mobile Office Networking Educational/Classroom Use

ADVANTAGES OF WLAN

Mobility is primary advantage of wireless technology

Easier and Less Expensive Installation: Installing network cabling in older buildings difficult and costly

Increased Reliability

DISADVANTAGES OF WLAN Security: Wireless signals broadcast in open air Security for wireless LANs is the prime concern Unauthorized users might access network Attackers might view transmitted data Employees could install rogue access points Attackers could easily crack existing wireless security Radio Signal Interference: Signals from other devices

can disrupt wireless transmissions Health Risks: Wireless devices emit RF energy

SUMMARY Review OSI, Protocol, IP Private, IP Public Dynamic IP, Static IP Enthenet 802.3 Today’s Wireless LAN Standards 802.11, 802.11a, 802.11b+, 802.11g,

802.11h Infracstructure WLAN, WPAN, WMAN, WWAN

SUMMARY Roles Organizations Play Within the WLAN Industry

The Federal Communications Commission

(FCC) is an example of regulatory bodies The Institute of Electrical and Electronics

Engineers (IEEE) is an example of a standards development organization

The Wi-Fi Alliance is a compatibility testing and certification group