1. IS3120 Network Communications Infrastructure
Unit 5
IEEE a/b/g/h/i/n Wireless LANs

2. Class Agenda 4/15/16 Learning Objectives
Lesson Presentation and Discussions.
Discussion on Assignments.
Discussion on Lab Activities.
Break Times as per School Regulations.

3. Learning Objective
Align the wireless standards and security methodologies used to increase business productivity.

4. Key Concepts
Overview of IEEE wireless LAN standards and specifications
IEEE a/b/g/h/n
IEEE i and layered security strategies for WLANs
Wireless LAN design:
Wireless access points (WAPs)
SSID broadcasting versus stealth
RF site surveys
Workgroup WLANs
Broadband/backbone WLANs

5. EXPLORE: CONCEPTS

6. OSI Model and IEEE

7. Max. Data Rate in Megabits per Second (Mbps) Range (Indoor/ Outdoor)
Comparing x Standards
Standard
Band (GHz)
Max. Data Rate in Megabits per Second (Mbps)
Range (Indoor/ Outdoor)
in Feet
802.11a 5 54
115/390
802.11b
2.4 11
125/460
802.11g
802.11n
2.4 or 5
600*
230/820
* Typical rate is 144 Mbps

8. IEEE 802.11a Typical throughput in mid-20 Mbps
9/22/2018
IEEE a
Typical throughput in mid-20 Mbps
Uses a 52-subcarrier orthogonal frequency-division multiplexing (OFDM)
Restricted almost to line of sight
Cannot penetrate as far as b/g because it’s absorbed more readily
(c) ITT Educational Services, Inc.

9. MULTIPLEXING
Whenever the bandwidth of a medium linking two devices is greater than the bandwidth needs of the devices, the link can be shared. Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. As data and telecommunications use increases, so does traffic.

10. Figure 6.1 Dividing a link into channels

11. Figure 6.2 Categories of multiplexing

12. IEEE 802.11b The first wireless standard in use
9/22/2018
IEEE b
The first wireless standard in use
Less susceptible to corruption
Uses Adaptive Rate Selection (ADS)
Scales back as signal quality decreases
Less susceptible to corruption due to interference and signal attenuation
Uses the Complementary Code Keying (CCK) RF signal format.
This is a slight variation on Code Division Multiple Access (CDMA ) that uses the basic Direct Sequence Spread Spectrum (DSSS ) as its basis.
1 Mbps
2 Mbps
11 Mbps
5.5 Mbps
(c) ITT Educational Services, Inc.

13. IEEE 802.11g Most wireless adapters support 802.11g
9/22/2018
IEEE g
Most wireless adapters support g
Backwards-compatible with b
Compatible with a if WAP broadcasts in both 2.4 GHz and 5 GHz ranges
Incorporates OFDM to achieve higher data transfer rates
Can scale back to 11 Mbps or lower
(c) ITT Educational Services, Inc.

14. IEEE 802.11n Highly popular today
9/22/2018
IEEE n
Highly popular today
Backwards-compatible with a/b/g
40 MHz maximum channel bandwidth
Supports up to 4 MIMO spatial streams
Can interfere with:
Other systems using 2.4 frequency
Non systems such as Bluetooth
(c) ITT Educational Services, Inc.

15. MIMO
MIMO stands for multiple-input multiple-output, where multiple refers to multiple antennas used simultaneously for transmission and multiple antennas used simultaneously for reception, all over a radio channel.

16. IEEE 802.11h Amendment to IEEE 802.11 standard
9/22/2018
IEEE h
Amendment to IEEE standard
Solves interference on the 5 GHz frequency band
Defines how a devices implement:
Dynamic Frequency Selection (DFS)
Transmitter Power Control (TPC)
(c) ITT Educational Services, Inc.

17. The Future: IEEE 802.11ac High throughput WLAN in the 5 GHz band
9/22/2018
The Future: IEEE ac
High throughput WLAN in the 5 GHz band
Multi-station WLAN throughput
Minimum 1 Gigabit per second
Maximum single link throughput of at least 500 Mbps
80 MHz and 160 MHz channel bandwidths
Up to 8 MIMO spatial streams
(c) ITT Educational Services, Inc.

18. SSID Broadcasting versus Stealth
9/22/2018
SSID Broadcasting versus Stealth
SSID Broadcasting
Stealth Mode
Hi, I’m WGABLDG5!
SSID Broadcasting
Service Set Identifier (SSID) is the name you give your wireless network. Makes it easy for users to identify particular WAPs when deciding which WAP to connect to.
A WAP transmits beacon frames, which includes the WAP’s SSID.
Wireless nodes receive beacon frame, determine if they want to associate with the WAP transmitting the beacon.
A wireless station transmits probe frames, which include its station ID and the SSID.
You can map SSIDs to virtual LANs; thus, some APs support multiple SSIDs.
Stealth Mode
Stealth mode also known as closed mode, closed network, or private network.
A stealth WAP or broadband Wi-Fi router hides itself by not broadcasting its SSID; the SSID doesn’t appear in wireless network lists.
To connect to a stealth WAP or router, you must know the SSID and configure your device to access the WAP or router.
Wireless Router
Wireless Router
(c) ITT Educational Services, Inc.

19. EXPLORE: PROCESSES

20. Site/RF Surveys Understand requirements Get diagram
9/22/2018
Site/RF Surveys
Understand requirements
Get diagram
Inspect environment
Assess environment
Identify coverage area
Determine WAP locations
For an excellent step-by-step, see Jim Grier’s full instructions at
1. Understand wireless requirements.
2. Get a building diagram.
3. Visually inspect the environment.
4. Assess existing network environment.
5. Identify coverage area.
6. Determine preliminary WAP locations.
(c) ITT Educational Services, Inc.

21. Design a WLAN Conduct RF survey and physical site assessment
9/22/2018
Design a WLAN
Conduct RF survey and physical site assessment
Assess type of users who will use WLAN
Determine which applications users and administrators need
Determine type of traffic that will use WLAN
Map out core, aggregation, and access layers
(c) ITT Educational Services, Inc.

22. Design a WLAN Create coverage map (if not done during RF survey)
9/22/2018
Design a WLAN
Create coverage map (if not done during RF survey)
Create security scheme
Authorization, access control, encryption
Route external connections through a firewall
(c) ITT Educational Services, Inc.

23. Create Gap-Free WLAN Security
9/22/2018
Create Gap-Free WLAN Security
Locate networking equipment in secure locations
Install or check settings of firewalls, IDS/IPS, other security devices
Lock down workstations and servers, update/patch regularly
Locate WAP or wireless router outside the firewall if connected to a wired network
If you have a wired network, locate your WAP or wireless router outside the firewall. If intruders penetrate your Wi-Fi network, they will not be able to access your wired network.
(c) ITT Educational Services, Inc.

24. Create Gap-Free WLAN Security
9/22/2018
Create Gap-Free WLAN Security
Strategically position WAPs
Disable SSID broadcasting
Enable all security features on WLAN devices
Authentication
Encryption
(c) ITT Educational Services, Inc.

25. EXPLORE: ROLES

26. WLAN Security Roles Authentication Access Control Encryption 9/22/2018
Authentication and Access Control
Authentication should allow both the originating station of transmitted data and the receiving station to verify each other.
WAPs should use authentication and access control to grant access rights to requesting stations.
Encryption and Data Privacy
Encryption is a method that provides data integrity and privacy.
Use Wi-Fi Protected Access 2 (WPA2), also known as IEEE i, as the security protocol for encrypted communications with Extensible Authentication Protocol (EAP).
(c) ITT Educational Services, Inc.

27. EXPLORE: CONTEXTS

28. WiMAX Specified in IEEE 802.16
9/22/2018
WiMAX
Specified in IEEE
Like n but wider range and better Quality of Service (QoS)
Transmits up to 70 Mbps
Access up to 30 miles (fixed stations), 3 to 10 miles (mobile stations)
Line of sight not needed
Ideal for metropolitan area networks
Defines both the MAC and PHY layers and allows multiple PHY-layer specifications
(c) ITT Educational Services, Inc.

29. WiMAX (Worldwide Interoperability for Microwave Access)
Is a wireless industry coalition dedicated to the advancement of IEEE standards for broadband wireless access (BWA) networks.

30. WiMAX Internet Fixed backhaul 9/22/2018
Defines both the MAC and PHY layers and allows multiple PHY-layer specifications
Internet
Fixed backhaul
(c) ITT Educational Services, Inc.

31. WiMAX as Backbone for WAPs
9/22/2018
WiMAX as Backbone for WAPs
Wireless Router
Wireless Router
Wireless Router
Internet
(c) ITT Educational Services, Inc.

32. Summary In this presentation, the following were covered:
IEEE a/b/g/h/i/n standards and specifications
SSID broadcasting versus stealth mode
WLAN design considerations and processes
WLAN security considerations
WLAN and WiMAX backbones

33. Assignment 5.3 A WLAN Solution
Assignments
Discussion 5.1 Advantages and Disadvantages of Wired and Wireless Networks
Assignment 5.3 A WLAN Solution