1. Ch. 1 – Introduction to Wireless LANs

2. First Meeting Agenda – 8/23/04
Wireless Networks
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

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

4. Overview

5. 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.

6. 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, IrDA)
Radio frequencies (RFs)
Can penetrate ‘most’ office obstructions

7. 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
802.11b and g: GHz
C-Band ISM
802.11a: – GHz

8. IEEE 802.11 and the Wi-Fi Alliance
IEEE LAN/MAN Standards Committee (LMSC)
First standard released in 1997, several since then
Wireless Ethernet Compatibility Alliance (WECA)
Advertises its Wi-Fi (wireless fidelity) program
Any vendor can have its products tested for interoperability
Cisco is a founding member

9. 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)

10. Why Wireless?

11. Current Standards – a, b, g
Radio
Network
Speed
860 Kbps
900 MHz
1 and 2 Mbps
2.4 GHz
Proprietary
1 and 2 Mbps
11 Mbps
54 Mbps
Standards-based
2.4 GHz
5 GHz
IEEE Begins Drafting
Ratified
802.11a,b Ratified
802.11g Ratified
1986
1988
1990
1992
1994
1996
1998
2000
2003
802.11a
Up to 54 Mbps
5 GHz
Not compatible with either b or g
802.11b
Up to 11 Mbps
2.4 GHz
802.11g
802.11g is backwards compatible with b, but with a drawback (later)

12. 802.11 PHY (Physical Layer) Technologies
Radio
Network
Speed
860 Kbps
900 MHz
1 and 2 Mbps
2.4 GHz
Proprietary
1 and 2 Mbps
11 Mbps
54 Mbps
Standards-based
2.4 GHz
5 GHz
IEEE Begins Drafting
Ratified
802.11a,b Ratified
802.11g Ratified
1986
1988
1990
1992
1994
1996
1998
2000
2003
Three types of radio transmission within the unlicensed 2.4-GHz frequency bands:
Frequency hopping spread spectrum (FHSS) b (not used)
Direct sequence spread spectrum (DSSS) b
Orthogonal frequency-division multiplexing (OFDM) g
One type of radio transmission within the unlicensed 5-GHz frequency bands:
Orthogonal frequency-division multiplexing (OFDM) a

13. WLAN Devices: Access Points
In-building Infrastructure
1200 Series (802.11a and b)
1100 Series (802.11b)

14. 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 b radio (upgradable to g with Advanced Encryption Standard (AES))
Dual-mode a and b support (upgradable to 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

15. WLAN Devices: Bridges Bridging 350 Series (802.11b) BR350 WGB350
1400 Series (802.11a)

16. 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 b radio with data rates up to 11 Mbps
Single 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
VxWorks 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

17. This bridge is for indoor use only.
Bridges – WGB350
Cisco Aironet 350 Series Workgroup Bridge (WGB350) 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 b AP or Wireless Bridge.
This bridge is for indoor use only.

18. Wireless LAN Devices: Antennas
2.4GHz Antennas
5 GHz Antennas Indoor Vs Outdoor

19. Antennas 2.4 GHz 5 GHz Indoor and Outdoor WLAN and Bridging Bridging

20. Wireless LAN Devices: Cable, Accessories, Wireless IP Phone
Cable and Accessories
Low Loss Cable
Antenna Mounts
Lightening Arrestor
Wireless IP Phone

21. Wireless LAN Devices: Client Adapters
Clients (NICs)
350 Series (802.11b)
5 GHz client adapter (802.11a)
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.

22. Cisco Aironet 350 Series Mini PCI Adapter
2.4 GHz/802.11b embedded wireless for notebooks
100 mW transmit power
Must order through PC manufactures (not orderable directly through Cisco)

23. “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

24. Consumer wireless products
There is a real difference in functionality and administrative capabilities between Business-class and Consumer wireless products.

25. Wireless LAN Topologies

26. 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.

27. Four main requirements for a WLAN solution
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 CiscoWorks 2000, Cisco Stack Manager, and Cisco Resource Monitor.
Open architecture — Openness is achieved through adherence to standards such as a and b, participation in interoperability associations such as the Wi-Fi Alliance, and certification such as U.S. FCC certification.

28. 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.

29. Radio Signal Interference
Network managers must ensure that different channels are utilized.
Because the 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.

30. Radio Signal Interference

31. Power Consumption

32. 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)

33. Wireless LAN Security: IEEE, and WiFi Efforts
The IEEE enhanced Wired Equivalent Privacy (WEP) with Temporal Key Integrity Protocol (TKIP) which provides robust authentication options with 802.1x to make based wireless LANs secure.
We will also look at WPA (WiFi 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 i standard.

34. Installation and Site Design Issues—Bridging

35. Installation and Site Design Issues—WLAN

36. Health Issues

37. IEEE 802.11 Standards Activities
802.11a: 5GHz, 54Mbps
802.11b: 2.4GHz, 11Mbps
802.11d: Multiple regulatory domains
802.11e: Quality of Service (QoS)
802.11f: Inter-Access Point Protocol (IAPP)
802.11g: 2.4GHz, 54Mbps
802.11h: Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC)
802.11i: Security
802.11j: Japan 5GHz Channels ( GHz)
802.11k: Measurement