CCNA – Semester 3

Chapter 7: Basic Wireless

Concepts and Configuration

CCNA Exploration 4.0

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Objectives

• Describe the components and operations of basic

wireless LAN topologies.

• Describe the components and operations of basic

wireless LAN security.

• Configure and verify basic wireless LAN access.

• Configure and troubleshoot wireless client access.

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The Wireless LAN

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Why Use Wireless?

• Business networks today are evolving to support people who

are on the move.

• Mobility environment: where people can take their

connection to the network along with them on the road.

• There are many different infrastructures (wired LAN, service

provider networks) that allow mobility like this to happen, but

in a business environment, the most important is the WLAN.

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

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Wireless Technologies

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Wireless LAN

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Comparing a WLAN to a LAN

• In an 802.3 Ethernet LAN, each client has

a cable that connects the client NIC to a

switch. The switch is the point where the

client gains access to the network.

• In a wireless LAN, each client uses a

wireless adapter to gain access to the

network through a wireless device such as

a wireless router or access point.

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Wireless standards

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Wireless Infrastructure Components

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Configurable Parameters for Wireless

Endpoints

• Wireless mode

• Wireless Network Name: SSID

• Wireless Channel:

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802.11 Topologies: Ad hoc Network

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802.11 Topologies: Basic Service Sets

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802.11 Topologies: Extended Service

Sets

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Client and Access Point Association

• Beacon

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Client and Access Point Association

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Client and Access Point Association

Step 3 - 802.11 Association

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Planning the Wireless LAN

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Planning the Wireless LAN

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Planning the Wireless LAN

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Planning the Wireless LAN

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Wireless LAN Security

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Wireless LAN Security Threats

Unauthorized Access

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Wireless LAN Security Threats

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Wireless LAN Security Threats

Denial of Service

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Wireless Security Protocols

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Wireless Security Protocols

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Wireless Security Protocols

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Wireless Security Protocols

• Encryption

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Securing a Wireless LAN

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Configure Wireless LAN Access

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Configuring the Wireless Access Point

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Setup: Basic Setup

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Administration: Management

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Configuring Basic Wireless Settings

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Security Mode

• Select the mode you want to use: PSK-Personal, PSK2-

Personal, PSK-Enterprise, PSK2-Enterprise, RADIUS, or

WEP.

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Mode Parameters

• Enterprise modes are not configured in this chapter

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Configure Encryption and Key

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Configure a wireless NIC: Scan SSID

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Configure a wireless NIC: Scan SSID

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Select the Wireless Security Protocol

• Practice: 7.3.2.4

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Troubleshooting

Simple WLAN Problems

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Systematic Approach to WLAN

Troubleshooting

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

problem.

• Step 2 - Confirm the physical status of WLAN devices.

• Step 3 - Inspect wired links.

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Updating the Access Point Firmware

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Incorrect Channel Settings

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Incorrect Channel Settings: Solution

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Solving RF Interference

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Solving RF Interference

• Site Surveys

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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. A

site evaluation involves inspecting the area with the goal of

identifying potential issues that could impact the network.

Specifically, look for the presence of multiple WLANs,

unique building structures, such as open floors and

atriums, and high client usage variances, such as those

caused by differences in day or night shift staffing levels.

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

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Access Point Misplacement

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Access Point Misplacement: Solution

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Access Point Misplacement: Solution

• Ensure that access points are not mounted closer than 7.9 inches (20

cm) from the body of all persons.

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

obstructions.

• Install the access point away from microwave ovens. Microwave ovens

operate on the same frequency as the access point and can cause

signal interference.

• Always mount the access point vertically (standing up or hanging

down).

• 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. The

access point internal antennas are not omnidirectional and cover a

larger area when mounted this way.

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Problems with Authentication and Encrytion

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Problems with Authentication and Encrytion

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Problems with Authentication and Encrytion

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Summary

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