Chapter 7: Basic Wireless Concepts and Configuration

Chapter 7: Basic WirelessConcepts and Configuration

CCNA Exploration 4.0

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CCNA Exploration 4.0

Objectives

• Describe the components and operations of basicwireless LAN topologies.

• Describe the components and operations of basicwireless LAN security.

• Configure and verify basic wireless LAN access.• Configure and troubleshoot wireless client access.

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• Describe the components and operations of basicwireless LAN topologies.

• Describe the components and operations of basicwireless LAN security.

• Configure and verify basic wireless LAN access.• Configure and troubleshoot wireless client access.

The Wireless LAN


Why Use Wireless?

• Business networks today are evolving to support peoplewho are on the move.

• Mobility environment: where people can take theirconnection to the network along with them on the road.

• There are many different infrastructures (wired LAN,service provider networks) that allow mobility like this tohappen, but in a business environment, the most importantis the WLAN.

• People now expect to be connected at any time and place


• Business networks today are evolving to support peoplewho are on the move.

• Mobility environment: where people can take theirconnection to the network along with them on the road.

• There are many different infrastructures (wired LAN,service provider networks) that allow mobility like this tohappen, but in a business environment, the most importantis the WLAN.

• People now expect to be connected at any time and place

Wireless Technologies


PAN(Personal Area

Network)

LAN(Local Area Network)

WAN(Wide Area Network)

MAN(Metropolitan Area Network)

Wireless Will Be Everywhere


PAN(Personal Area

Network)

Wireless LAN


Comparing a WLAN to a LAN


• In an 802.3 Ethernet LAN, each client hasa cable that connects the client NIC to aswitch. The switch is the point where theclient gains access to the network.

• In a wireless LAN, each client uses awireless adapter to gain access to thenetwork through a wireless device such asa wireless router or access point.

What is WLAN RF Technology?


Modulation


802.11b Radio Modulation


802.11b Direct Sequence Modulation


2.4-GHz Channel Sets


802.11b Access Point Coverage


802.11b Scalability


Comparing the Technologies 802.11a Data Rates


802.11a Uses OFDM Modulation


802.11a 5-GHz Frequency Bands


802.11a Access Point Coverage


802.11a Scalability (Indoor UNII-1 and UNII-2)


Wireless standards


Wireless Infrastructure Components


Configurable Parameters for Wireless Endpoints

• Wireless mode• Wireless Network Name: SSID• Wireless Channel:


802.11 Topologies: Ad hoc Network


802.11 Topologies: Basic Service Sets


802.11 Topologies: Extended Service Sets


802.11 Frame Format


802.11 Frames Type

• There are three types of MAC frames, namely:• Control Frame:

– RTS, CTS, ACK• Data Frame• Management Frame:

– Beacon– Probe Req, Probe Resp– Assoc Req, Assoc Resp– Reassoc Req, Reassoc Resp– Disassociation– Authentication– Deauthentication


• There are three types of MAC frames, namely:• Control Frame:

– RTS, CTS, ACK• Data Frame• Management Frame:

– Beacon– Probe Req, Probe Resp– Assoc Req, Assoc Resp– Reassoc Req, Reassoc Resp– Disassociation– Authentication– Deauthentication

802.11 Frames Type (cont)


Client and Access Point Association

• Beacon



Step 3 - 802.11 Association


Planning the Wireless LAN


Wireless LAN Security


Wireless LAN Security Threats

Unauthorized Access



Denial of Service


Wireless Security Protocols


Authentication and Encryption


802.11 Open Authentication


802.11 Shared Key Authentication



• Encryption


Securing a Wireless LAN


Configure Wireless LAN Access


Configuring the Wireless Access Point


Setup: Basic Setup


Administration: Management


Configuring Basic Wireless Settings


Security Mode


• Select the mode you want to use: PSK-Personal, PSK2-Personal, PSK-Enterprise, PSK2-Enterprise, RADIUS, orWEP.

Mode Parameters


• Enterprise modes are not configured in this chapter

Configure Encryption and Key


Configure a wireless NIC: Scan SSID


Select the Wireless Security Protocol


• Practice: 7.3.2.4

TroubleshootingSimple WLAN Problems


TroubleshootingSimple WLAN Problems

Systematic Approach to WLAN Troubleshooting


• Step 1 - Eliminate the client device as the source of theproblem.

• Step 2 - Confirm the physical status of WLAN devices.• Step 3 - Inspect wired links.

Updating the Access Point Firmware


Incorrect Channel Settings


Incorrect Channel Settings: Solution


Solving RF Interference


Solving RF Interference

• Site Surveys


Site Survey

• Two categories: Manual and utility assisted.• Manual site surveys can include a site evaluation to be

followed by a more thorough utility-assisted site survey. Asite evaluation involves inspecting the area with the goal ofidentifying potential issues that could impact the network.Specifically, look for the presence of multiple WLANs,unique building structures, such as open floors andatriums, and high client usage variances, such as thosecaused by differences in day or night shift staffing levels.

• Note: you do not conduct site surveys as part of this course


• Two categories: Manual and utility assisted.• Manual site surveys can include a site evaluation to be

followed by a more thorough utility-assisted site survey. Asite evaluation involves inspecting the area with the goal ofidentifying potential issues that could impact the network.Specifically, look for the presence of multiple WLANs,unique building structures, such as open floors andatriums, and high client usage variances, such as thosecaused by differences in day or night shift staffing levels.

• Note: you do not conduct site surveys as part of this course

Access Point Misplacement


Access Point Misplacement: Solution


Access Point Misplacement: Solution

• Ensure that access points are not mounted closer than 7.9 inches (20cm) from the body of all persons.

• Do not mount the access point within 3 feet (91.4 cm) of metalobstructions.

• Install the access point away from microwave ovens. Microwave ovensoperate on the same frequency as the access point and can causesignal interference.

• Always mount the access point vertically (standing up or hangingdown).

• Do not mount the access point outside of buildings.• Do not mount the access point on building perimeter walls, unless

outside coverage is desired.• When mounting an access point in the corner of a right-angle hallway

intersection, mount it at a 45-degree angle to the two hallways. Theaccess point internal antennas are not omnidirectional and cover alarger area when mounted this way.


• Ensure that access points are not mounted closer than 7.9 inches (20cm) from the body of all persons.

• Do not mount the access point within 3 feet (91.4 cm) of metalobstructions.

• Install the access point away from microwave ovens. Microwave ovensoperate on the same frequency as the access point and can causesignal interference.

• Always mount the access point vertically (standing up or hangingdown).

• Do not mount the access point outside of buildings.• Do not mount the access point on building perimeter walls, unless

outside coverage is desired.• When mounting an access point in the corner of a right-angle hallway

intersection, mount it at a 45-degree angle to the two hallways. Theaccess point internal antennas are not omnidirectional and cover alarger area when mounted this way.

Problems with Authentication and Encrytion


Summary


Chapter 7: Basic Wireless Concepts and Configuration

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Transcript of Chapter 7: Basic Wireless Concepts and Configuration