Ch 1 Introduction to Wireless LANs Wireless Networks

Ch. 1 – Introduction to Wireless LANs

Wireless Networks 1. 2. 3. 4. 5. First Meeting Agenda – 8/23/04 Syllabus and Intro. How to access class resources in your computer Let’s get acquainted (forming groups) – Name – Industry certification – Networking or IT courses – Do you have a Cisco Academy account? – Interests – Why you are taking the class – Expectations of yourself – Expectations of the instructor and the class Creating students accounts in the Cisco database How to get to the online curriculum from home Rick Graziani graziani@cabrillo. edu 2

First Meeting Agenda – 8/23/04 (continued) 6. 7. Fifteen minutes break Lab setup (Images, passwords, NICs, patch panel, equipment, hostnames, SSIDs, and Network IDs) 8. Personal laptops and using the Cisco Aironet Wireless Cards 9. Resetting The access points 10. Access Point Web Interface and Basic Configuration Rick Graziani graziani@cabrillo. edu 3

Overview Rick Graziani graziani@cabrillo. edu 4

What is a wireless LAN? • Wireless LAN (WLAN) - provides all the features and benefits of traditional LAN technologies such as Ethernet and Token Ring, but without the limitations of wires or cables. Rick Graziani graziani@cabrillo. edu 5

What is a wireless LAN? • • WLAN, like a LAN, requires a physical medium to transmit signals. Instead of using UTP, WLANs use: – Infrared light (IR) • Next to visible light in the light spectrum • limitations, easily blocked, requires line of sight (unless diffused), maximum of 50 feet, data rate of only 4 Mbps • Best suited for data transmissions between laptops and printer at 115 Kbps directed transmission. (Ir Data Association, Ir. DA) – Radio frequencies (RFs) • Can penetrate ‘most’ office obstructions Rick Graziani graziani@cabrillo. edu 6

What is a wireless LAN? More later! • • WLANs use the 2. 4 GHz and 5 -GHz frequency bands. ISM (Industry, Scientific, Medical) license-free (unlicensed) frequency bands. S-Band ISM – 802. 11 b and 802. 11 g: 2. 4 - 2. 5 GHz C-Band ISM – 802. 11 a: 5. 725 – 5. 875 GHz Rick Graziani graziani@cabrillo. edu 7

IEEE 802. 11 and the Wi-Fi Alliance • • IEEE LAN/MAN Standards Committee (LMSC) – First 802. 11 standard released in 1997, several since then Wireless Ethernet Compatibility Alliance (WECA) – Advertises its Wi-Fi (wireless fidelity) program – Any 802. 11 vendor can have its products tested for interoperability – Cisco is a founding member Rick Graziani graziani@cabrillo. edu 8

Other Wireless Technologies • • • Communicates through small radio transceivers called radio modules. Can transmit data at up to 1 Mbps over a distance of 33 feet Can send data through physical barriers such as walls Does not need line of sight Uses a link manager which is a special software used to identify other Bluetooth devices and create links with them (PAN) Rick Graziani graziani@cabrillo. edu 9

Why Wireless? http: //www. cisco. com/en/US/netsol/ns 473/networking_soluti ons_package. html Rick Graziani graziani@cabrillo. edu 10

Current Standards – a, b, g Speed 860 Kbps Radio 900 MHz 2. 4 GHz 1986 • • • Standards-based Proprietary Network 1988 11 Mbps 54 Mbps 1 and 2 Mbps 1990 IEEE 802. 11 Begins Drafting 1992 1994 5 GHz 2. 4 GHz 1996 802. 11 Ratified 802. 11 a, b 802. 11 g Ratified 1998 2000 802. 11 a – Up to 54 Mbps – 5 GHz – Not compatible with either 802. 11 b or 802. 11 g 802. 11 b – Up to 11 Mbps 802. 11 g is backwards compatible – 2. 4 GHz with 802. 11 b, but with a drawback 802. 11 g (later) – Up to 54 Mbps – 2. 4 GHz Rick Graziani graziani@cabrillo. edu 2003 11

802. 11 PHY (Physical Layer) Technologies Speed 860 Kbps Radio 900 MHz 2. 4 GHz 1986 • • Standards-based Proprietary Network 1988 11 Mbps 54 Mbps 1 and 2 Mbps 1990 IEEE 802. 11 Begins Drafting 1992 1994 5 GHz 2. 4 GHz 1996 802. 11 Ratified 802. 11 a, b 802. 11 g Ratified 1998 2000 2003 Three types of radio transmission within the unlicensed 2. 4 -GHz frequency bands: – Frequency hopping spread spectrum (FHSS) 802. 11 b (not used) – Direct sequence spread spectrum (DSSS) 802. 11 b – Orthogonal frequency-division multiplexing (OFDM) 802. 11 g One type of radio transmission within the unlicensed 5 -GHz frequency bands: – Orthogonal frequency-division multiplexing (OFDM) 802. 11 a Rick Graziani graziani@cabrillo. edu 12

WLAN Devices: Access Points In-building Infrastructure • 1200 Series (802. 11 a and 802. 11 b) • 1100 Series (802. 11 b) Rick Graziani graziani@cabrillo. edu 13

Cisco Aironet WLAN Solutions for the Enterprise Cisco Aironet 1100 Series Cisco Aironet 1200 Series Intelligent Enterprise Services at a Lower Total Cost Outstanding Enterprise Performance and Greatest Flexibility Single 802. 11 b radio (upgradable to 802. 11 g with Advanced Encryption Standard (AES)) Dual-mode 802. 11 a and 802. 11 b support (upgradable to 802. 11 g with Advanced Encryption Standard (AES)) Integrated diversity dipole antennas for simplified deployment Two 2. 4 GHz antenna connectors for high gain diversity antennas; integrated 5 GHz antennas Indoor environmental specifications, durable plastic case Industrial environmental specifications, rugged metal case Extra memory and system capacity for future releases Inline and Local Power Cisco IOS-based operating system Cisco IOS operating system QOS, VLANs, and Proxy Mobile IP Rick Graziani graziani@cabrillo. edu 14

WLAN Devices: Bridges • Bridging – 350 Series (802. 11 b) • BR 350 • WGB 350 – 1400 Series (802. 11 a) Rick Graziani graziani@cabrillo. edu 15

Cisco Aironet Wireless Bridging Solutions Cisco Aironet 350 Series Cisco Aironet 1400 Series Wireless Bridging at a Lower Total Cost Wireless Bridging with high performance Single 802. 11 b radio with data rates up to 11 Mbps Single 802. 11 a radio with data rates up to 54 Mbps 3 miles typical point to point range with directional antennas at 11 Mbps 7. 5 miles typical point to point range with directional antennas at 54 Mbps Two 2. 4 GHz antenna connectors for high gain diversity antennas Single 5. 8 GHz integrated patch array antenna or antenna connector for remote antennas Indoor industrial environmental specifications, rugged metal case Outdoor environmental specifications, tested to NEMA 4 Inline and Local Power Inline Power via Power Injector LR Vx. Works based operating system Cisco IOS operating system QOS, VLANs, and Proxy Mobile IP Statistics via telnet Antenna Alignment feedback via LEDs and RSSI port and statistics via telnet Rick Graziani graziani@cabrillo. edu 16

Bridges – WGB 350 • Cisco Aironet 350 Series Workgroup Bridge (WGB 350) quickly connects up to eight Ethernet-enabled laptops or other portable computers to a wireless WLAN, providing an 11 Mbps link from these devices to any Cisco Aironet 802. 11 b AP or Wireless Bridge. • This bridge is for indoor use only. Rick Graziani graziani@cabrillo. edu 17

Wireless LAN Devices: Antennas Antenna • 2. 4 GHz Antennas • 5 GHz Antennas Indoor Vs Outdoor Rick Graziani graziani@cabrillo. edu 18

Antennas • • Indoor and Outdoor WLAN and Bridging • • Outdoor Bridging • • 5 GHz 2. 4 GHz Rick Graziani graziani@cabrillo. edu 19

Wireless LAN Devices: Cable, Accessories, Wireless IP Phone Cable and Accessories • Low Loss Cable • Antenna Mounts • Lightening Arrestor • Wireless IP Phone Rick Graziani graziani@cabrillo. edu 20

Wireless LAN Devices: Client Adapters Clients (NICs) • 350 Series (802. 11 b) • 5 GHz client adapter (802. 11 a) Drivers are supported for all popular operating systems, including Windows 95, 98, NT 4. 0, Windows 2000, Windows ME, Windows XP, Mac OS Version 9. x, and Linux. Rick Graziani graziani@cabrillo. edu 21

Cisco Aironet 350 Series Mini PCI Adapter • • • 2. 4 GHz/802. 11 b embedded wireless for notebooks 100 m. W transmit power Must order through PC manufactures (not orderable directly through Cisco) Rick Graziani graziani@cabrillo. edu 22

“Business-Class”vs Consumer WLAN • Industry has segmented: consumer vs. business • “Cisco” offers only “business-class” products: –Security –Upgradeability –Network management –Advanced features –Choice of antennas –Highest throughput –Scalability

Consumer wireless products • There is a real difference in functionality and administrative capabilities between Business-class and Consumer wireless products. Rick Graziani graziani@cabrillo. edu 24

Wireless LAN Topologies Rick Graziani graziani@cabrillo. edu 25

Wireless LAN Topologies • • • Without a wireless alternative, organizations frequently resort to wide area networking (WAN) technologies to link together separate facilities. Contracting for leased-line or other wide-area services often presents a variety of drawbacks: • Installation is typically expensive and rarely immediate • Monthly fees are often quite high for bandwidth A wireless bridge can typically be purchased and installed in a day with no recurring charges. Rick Graziani graziani@cabrillo. edu 26

Four main requirements for a WLAN solution 1. 2. 3. 4. High availability — High availability is achieved through system redundancy and proper coverage-area design. Scalability — Scalability is accomplished by supporting multiple APs per coverage area, which use multiple frequencies. APs can also perform load balancing, if desired. Manageability — Diagnostic tools represent a large portion of management within WLANs. Customers should be able to manage WLAN devices through industry standard APIs, including SNMP and Web, or through major enterprise management applications like Cisco. Works 2000, Cisco Stack Manager, and Cisco Resource Monitor. Open architecture — Openness is achieved through adherence to standards such as 802. 11 a and 802. 11 b, participation in interoperability associations such as the Wi-Fi Alliance, and certification such as U. S. FCC certification. Rick Graziani graziani@cabrillo. edu 27

Other requirements • • Security — It is essential to encrypt data packets transmitted through the air. For larger installations, centralized user authentication and centralized management of encryption keys are also required. Cost — Customers expect continued reductions in price of 15 to 30 percent each year, and increases in performance and security. Customers are concerned not only with purchase price but also with total cost of ownership (TCO), including costs for installation. Rick Graziani graziani@cabrillo. edu 28

Radio Signal Interference • • • Network managers must ensure that different channels are utilized. Because the 802. 11 standards use unlicensed spectrum, changing channels is the best way to avoid interference. If someone installs a link that interferes with a wireless link, the interference is probably mutual. Rick Graziani graziani@cabrillo. edu 29

Radio Signal Interference Rick Graziani graziani@cabrillo. edu 30

Power Consumption Rick Graziani graziani@cabrillo. edu 31

Wireless LAN Security: Lessons “War Driving” Hacking into WEP Lessons: • Security must be turned on (part of the installation process) • Employees will install WLAN equipment on their own (compromises security of your entire network) • WEP keys can be easily broken (businesses need better security) Rick Graziani graziani@cabrillo. edu 32

Wireless LAN Security: IEEE, and Wi. Fi Efforts • • The IEEE enhanced Wired Equivalent Privacy (WEP) with Temporal Key Integrity Protocol (TKIP) which provides robust authentication options with 802. 1 x to make 802. 11 based wireless LANs secure. We will also look at WPA (Wi. Fi Protected Access, TKIP + Message Integrity Code “MIC”) At the same time, the IEEE is looking for stronger encryption mechanisms. The IEEE has adopted the use of the Advanced Encryption Standard (AES) to the data-privacy section of the proposed 802. 11 i standard. Rick Graziani graziani@cabrillo. edu 33

Installation and Site Design Issues—Bridging Rick Graziani graziani@cabrillo. edu 34

Installation and Site Design Issues—WLAN Rick Graziani graziani@cabrillo. edu 35

Health Issues Rick Graziani graziani@cabrillo. edu 36

IEEE 802. 11 Standards Activities • • • 802. 11 a: 5 GHz, 54 Mbps 802. 11 b: 2. 4 GHz, 11 Mbps 802. 11 d: Multiple regulatory domains 802. 11 e: Quality of Service (Qo. S) 802. 11 f: Inter-Access Point Protocol (IAPP) 802. 11 g: 2. 4 GHz, 54 Mbps 802. 11 h: Dynamic Frequency Selection (DFS) Transmit Power Control (TPC) 802. 11 i: Security 802. 11 j: Japan 5 GHz Channels (4. 9 -5. 1 GHz) 802. 11 k: Measurement Rick Graziani graziani@cabrillo. edu and 37