1. Dave Packham OIT Architecture Dave.packham@utah.edu
Campus Wireless
Dave Packham
OIT Architecture

2. Agenda IV. Wireless 101 - Dave Packham (45 minutes)
a. Overview of Wireless Technology (3500 foot level)
b. U of U Wireless Direction, Standards
i. ITC -> Wireless Committee
ii. White Paper: 802.1x, WPA
iii. Wireless Requirements for Task Force funding
c. Campus Today, Future
i. Friday meetings, wireless list
ii. Map of current zones
iii. Planned future zones
iv. Support via the Campus Help Desk
v. WAP registration

3. Credits and Noteworthy Contributors
Joe Breen and CHPC. For the wonderful lab facilities and dealing with us every Friday.
Chris Hessing and Terry Simons and the Library folk. For designing and pushing x and security in the wireless arena, willing to test out live networks for us to watch (Library 802.1x)
Panko’s Business Data Networks and Telecommunications, 5th edition Copyright 2005 Prentice-Hall
5G Wireless for the campus wide coverage maps
Cisco for some great slides on wireless antennas and spectrum
Wayne Peay and the Wireless working group. That has facilitated us to unite and develop many new ideas. To work on campus wide deployment of COMMON authentication look and feel
Steve Hess and OIT for the resources to deploy products like Perfigo campus wide.

4. Huge Number of 802.11-Enabled Devices and Growing
HP iPAQ PDA
Cisco 7920
Epson Printer
PDAs
Printers
Projectors
Tablet PCs
Barcode scanners
Custom devices for vertical markets:
Healthcare
Manufacturing
Retail
Restaurants
Sharp M25X Projector
HHP Barcode Scanner
Compaq Tablet PC 4

5. Market Realities
802.11b
Dominates the installed base but not for sale much longer because of g
802.11g dominates sales today
802.11a is not thriving in the market
802.11n is under development
100 Mbps or more in the 5 GHz band
Fast enough for video

6. Antennas Yaggi Dish Directional Unidirectional Hemispherical
Toroidal Active Antennas
Energy beams
Mass transfer conversion
Transporters
Anti matter nacelles and warp drive

7. Omnidirectional and Directional Antennas
Dish Antenna
Concentrates incoming and outgoing
signals in a narrow range
-----
Must point at receiver
Good for fixed subscribers
Omnidirectional Antenna
Signal spreads as a sphere
Rapid signal attenuation
-----
No need to point at receiver
Good for mobile subscribers

8. Wireless Propagation Problems2.
Electromagnetic
Interference
(EMI) from
Other stations,
Microwave ovens, etc. 1.
Attenuation: signal gets
weaker with distance
Blocking
Object 3.
Shadow
Zone
(Dead Spot)
Direct Signal
Laptop
4. Multipath
Interference
Reflected Signal
Direct and reflected signals may cancel out

9. Radio Channels What are they? Why do the collide?
B/G Why are there only 3 distinct channels with 11 available?
A Why are there 56 channels?

10. Wireless Technologies
WAN
(Wide Area Network)
MAN
(Metropolitan Area Network)
LAN
(Local Area Network)
PAN
(Personal Area Network)
PAN
LAN
MAN
WAN
Standards
Bluetooth
802.11
GSM, CDMA, Satellite
Speed
< 1 Mbps
11 to 54 Mbps
Mbps
10 Kbps–2 Mbps
Range
Short
Medium
Medium-Long
Long
Applications
Peer-to-Peer Device-to-Device
Enterprise Networks
Last Mile Access
Mobile Data Devices

11. 802.11 Wireless LAN Standards (Table)
802.11g
802.11g
if g
access
point
serves an
802.11b
station
802.11a, operating at
a higher frequency,
has more attenuation
Than b
Rated Speed
11 Mbps
54 Mbps
54 Mbps
Not
Specified
Actual Throughput,
3 m
6 Mbps
25 Mbps
25 Mbps
12 Mbps
Actual Throughput,
30 m
6 Mbps
12 Mbps
20 Mbps
11 Mbps

12. 802.11 Wireless LAN Standards (Table)
802.11g
802.11g
if g
access
point
serves an
802.11b
station
Unlicensed Band
2.4 GHz
5 GHz
2.4 GHz
2.4 GHz
Number of Non-
Overlapping Channels 3
8 to 14
In future,
19 to 24 3 3
2.4 GHz non-overlapping channels are 1, 6, and 11

13. Using Different Channels in Nearby Access Points
Point A
Channel 1
Access
Point B
Channel 6
Access
Point C
Channel 6 OK
Interference OK
Interference OK
Interference OK
Access
Point D
Channel 6
Access
Point E
Channel 6
Access
Point F
Channel 11

14. Radio spectrum types
Frequency hopping
Spread spectrum

15. Normal Radio Transmission and Spread Spectrum Transmission
Why Spread Spectrum Transmission?
Commercial spread spectrum transmission reduces certain propagation effects (multipath interference and narrowband EMI);
These typically occur over a narrow range of frequencies
With spread spectrum transmission, most of the signal will get through
Does not provide security as in military spread spectrum systems (common misconception)

16. Frequency Hopping Frequency Time 2.483 GHz 9 8 7 6 5 4 3 2 1 2.400 GHz
79 Channels, 1 MHz Each
Changes frequency (Hops) at least every 0.4 seconds
Synchronized hopping required

17. Spread Spectrum Transmission Methods, Continued
Wideband but Low-Intensity Signal
Direct Sequence
Spread Spectrum
(DSSS)
Signal is spread over the entire bandwidth of the wideband channel
The power per hertz at any frequency is very low
Interference will harm some of the signal, but most of the signal will still get through and will be readable
Used in b (11 Mbps)

18. IEEE 802.11b Direct Sequence @ 2.4 GHz
Channels 1 2 3 4 5 6 7 8 9 10 11 12 13 14
2.402 GHz
2.483 GHz
Up to (14) 22 MHz wide channels
3 non-overlapping channels (1, 6,11 in US and 1,7,13 in Europe)
Up to 11 Mbps data rate
3 Access Points can occupy the same space for a total of 33 Mbps aggregate throughput, but not on same radio card

19. Frequency Hopping vs. Direct Sequence: A Summary on Interference Handling1 2 3
Channel 1
GHz
GHz
Frequency
Channel 2
Frequency
Interference
Channel 3
2.4 GHz
2.4 GHz
Time
FH system hops around interference
Data may be decoded from redundant bits
Can move to an alternate channel to avoid interference

20. Wireless Security
How?
What?
Where?
When?

21. Overview of Wireless Security Technologies
No Security by Default
In older products, the installation default was to have no security at all No
Security No
Security

22. WarChalking, WarDriving….
Automated Drive-By Hacking
Can read traffic from outside the building walls
Can also send malicious traffic into the network

23. Standard WEP
Wired Equivalent Privacy (WEP)
Initial flawed security method developed by the Working Group for devices
All stations share the same encryption key with the access point
This key is rarely changed because of the difficulty of coordinating the many users sharing it
This is a shared static key

24. Standard WEP
Wired Equivalent Privacy (WEP)
Shared static keys means that a large volume of traffic is encrypted with the same key
With so much traffic generated with one unchanging key, cryptanalysts can crack the key by collecting data for a few days
Once the key is cracked, the attacker can read all messages and send attack messages into the network without going through a firewall filter

25. Standard WEP
Wired Equivalent Privacy (WEP)
Software that automates the hacking process is widely available
Locate vulnerable access points by driving around (war driving)
Collect traffic and crack the key

26. VPN’s
Virtual Private Network (VPN)
VPNs protect transmission over the untrusted Internet (Chapter 1)
VPNs can also be used to protect transmission over the untrusted WLAN
Effective but complex and therefore expensive to set up

27. 802.11i Later, 802.11 Working Group introduced strong security
802.11i Security
Later, Working Group introduced strong security
802.11i
802.11i specifies the Temporal Key Integrity Protocol (TKIP)
Each station gets a separate key for confidentiality
This key is changed frequently

28. 801.11i 802.11i Specifies the Extensible Authentication Protocol (EAP)
802.11i Security
802.11i Specifies the Extensible Authentication Protocol (EAP)
Authentication involves a device proving its identity to another device
Authenticate with an authentication server (Figure 5-17)

29. Authentication Protocol (EAP)2.
Notebook
Access
Point A
EAP Data
Switch 3.
EAP Data
Authentication is stored on an authentication server, not in access points
This simplifies access points, making them cheaper
Central authentication data is easier to manage and change
Client PC
Authentication
Server
Large Wired Ethernet LAN

30. Authentication Protocol (EAP)4.
Notebook
Access
Point A
Switch OK
Accept OK
If an OK is sent back, the access point may accept an association request from the client
If a bad report is sent back, the access point may decline an association request from the client 4.
Client PC
Authentication
Server
Large Wired Ethernet LAN

32. 802.11 continued Products started becoming available soon?
802.11i Security
Products started becoming available soon?
Wireless Protected Access (WPA)
Stopgap security method introduced before full i security could be developed
Introduced some parts of i in 2002 and 2003
It was often possible to upgrade older WEP products to WPA

33. Stronger Security
The Transition to Strong Security
We will soon have a mix of no security, WEP, i, WPA, and other security protocols
Only as strong as the weakest link
Legacy equipment that cannot be upgraded to i will have to be discarded
(802.11i is sometimes called WPA2)

34. Security?
Rogue Access Points
Unauthorized access points set up by department or individual
Often have very poor security, leaving a big opening for hackers
Often operate at high power, attracting many clients to these access points with weak security

35. BlueTooth?
Where did this come from?
Why is it here?

36. BlueTooth Replace wired connections
Wireless standard for personal area networks (PANs)
Replace wired connections
A few devices that a person carries
A few devices on a user’s desktop

37. 802.11 vs BlueTooth 802.11 Bluetooth Focus Local Area Network (LAN)
Personal Area
Network (PAN)
Rated Speed
(Actual Throughput
Will Be Lower)
11 Mbps to 54 Mbps
in both directions
722 kbps with back
channel of 56 kbps.
May increase.
Distance
30 to 100 meters
10 meters
Number of Devices
Limited in practice
only by bandwidth
and traffic
10 piconets (PANs),
each with up to
8 devices

38. 802.11 vs BlueTooth 802.11 Bluetooth Scalability Good because
allows multiple
access points
Poor
Cost
Higher
Lower
Battery Drain
Higher
Lower
Application
Profiles No
Yes

39. Should I BlueTooth?
Bluetooth Application Profiles
Devices with compatible application profiles (a printer and PC, for instance) can work together automatically
Extremely useful; nothing like it in
However, few application profiles have been designed
Also, most Bluetooth devices only implement a few application profiles

41. Whats up Next?
Here comes the solution to everything……

42. Emerging WLAN Technologies
Fourth-Generation (4G) Stations
Stations that can support multiple radio methods
802.11a, b, and g
Bluetooth
3G cellular
Etc.
Choose the best mode for a situation
E.g., g when in reach of WLAN (fast & cheap)
Expensive 3G when nothing else is available

43. Mesh Networks Move frames to desired receiver peer-to-peer (P2P)
Access points and wireless NICs self-organize
Move frames to desired receiver peer-to-peer (P2P)
Adjust signal power, etc. when an element fails or is turned off

44. Expensive Directly-Manageable
The “Wireless Switch”
Expensive Directly-Manageable
Smart Access Point
Ethernet Switch
Dumb
Access Point
WLAN switch has the management intelligence for multiple inexpensive dumb access points
Management
Console
WLAN
Switch
Dumb
Access Point

45. Wireless on Campus
What
Where
When
Why

46. Friday meeting @ CHPC Every Friday at 10 am CHPC lab/conf room
Talk about hardware
Talk about software
Put together proposals for ITAC and Wireless working groups
Design and workout kinks in wireless networks on campus
Continue Radius mesh design and integration
Join the wireless groups mailing list for see news on this.

47. Campus WIDE Wireless Coverage

48. Student Task Force Wireless Requirements
Campus Wireless rollouts may be Task Force funded
Requirements are
Adhere to the Wireless Whitepaper policy
Agree to adopt to changing wireless environments
Provide “secure.utah.edu” for clients with an x supplicant
Provide “insecure.utah.edu for device that don’t support 802.1x
Request approved AP and wireless hardware
Provide these wireless services to every student

50. Wireless Links

51. ALL Wireless Problems Solved
Everyone's problems are solved
Nothing more can ever happen
I'm just done talking now….. 