Implementing Wireless and WLAN Chapter 19 powered by DJ 1

Chapter Objectives  Describe standards associated with wireless media  Identify and describe the purpose of the components in a small wireless network  Identify common issues with implementing wireless networks At the end of this Chapter you will be able to: powered by DJ 2

Introduction to Wireless Technology  Transmitting a signal using the typical specifications works a lot like it does with a basic Ethernet hub: They’re both two-way forms of communication, and they both use the same frequency to both transmit and receive, often referred to as half-duplex. Wireless LANs (WLANs) use radio frequencies (RFs) that are radiated into the air from an antenna that creates radio waves powered by DJ 3

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The Standards Committee Purpose IEEE a 54Mbps, 5GHz standard IEEE b Enhancements to to support 5.5 and 11Mbps IEEE c Bridge operation procedures; included in the IEEE 802.1D standard IEEE d International roaming extensions IEEE e Quality of service IEEE F Inter-Access Point Protocol IEEE g 54Mbps, 2.4GHz standard (backward compatible with b) IEEE h Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) at 5Ghz IEEE i Enhanced security IEEE j Extensions for Japan and U.S. public safety IEEE k Radio resource measurement enhancements powered by DJ 5

Conti... IEEE mMaintenance of the standard; odds and ends IEEE n Higher throughput improvements using MIMO (multiple input, multiple output antennas) IEEE p Wireless Access for the Vehicular Environment (WAVE) IEEE r Fast roaming IEEE s Extended Service Set (ESS) Mesh Networking IEEE T Wireless Performance Prediction (WPP) IEEE u Internetworking with non-802 networks (cellular, for example) IEEE v Wireless network management IEEE w Protected management frames IEEE y 3650–3700 operation in the U.S powered by DJ 6

Comparing powered by DJ 7

Wireless Topologies  Wireless topologies are:  Ad-hoc Topology  Infrastructure Topology powered by DJ 8

Ad-hoc Topology  Ad hoc wireless networks technically use an Independent Basic Service Set (IBSS) topology.  This means that each wireless device independently manages the wireless network. This type of wireless network originates from and includes the wireless device, as shown in Figure. powered by DJ 9

Infrastructure Topology  involves using a dedicated piece of equipment (typically a wireless access point) to initiate and manage the wireless network.  Wireless access points can be configured to use one of two infrastructure modes: Basic Service Set (BSS) or Extended Service Set (ESS). The BSS is the simplest form of wireless network. It includes a single wireless access point managing a group of clients, as shown in Figure. powered by DJ 10

Single basic service set design powered by DJ 11

An extended service set design powered by DJ 12

Wireless Security  Wireless Security – A Brief Overview Points:- SSIDs, WEP, and MAC Address Authentication  SSID is a common network name for the devices in a WLAN system that creates the wireless LAN. An SSID prevents access by any client device that doesn’t have the SSID.  Two types of authentication were specified by the IEEE committee: open and shared-key authentication. Open authentication involves little more than supplying the correct SSID—but it’s the most common method in use today. powered by DJ 13

Conti..  With shared-key authentication, the access point sends the client device a challenge-text packet that the client must then encrypt with the correct Wired Equivalency Protocol (WEP) key and return to the access point. Without the correct key, authentication will fail and the client won’t be allowed to associate with the access point  MAC addresses can be statically typed into each access point, and any of them that show up without that MAC addresses in the filter table would be denied access. powered by DJ 14

WPA or WPA 2 Pre-Shared Key  WPA or WPA2 Pre-Shared Key (PSK) is a better form of wireless security than any other basic wireless security method mentioned so far.  Wi-Fi Protected Access (WPA) is a standard developed in 2003 by the Wi-Fi Alliance, formerly known as WECA. WPA provides a standard for authentication and encryption of WLANs that’s intended to solve known security problems existing up to and including the year powered by DJ 15

Configuring Our Wireless Internetwork Interface and Connections powered by DJ 16

Conti.. Edit Interface Connection powered by DJ 17

Conti.. Wireless Express Setup powered by DJ 18

Conti.. SSID Configuration powered by DJ 19

Conti.. Network Interface Radio Settings powered by DJ 20

Conti.. Wireless Setting Configuration powered by DJ 21

Conti.. Security Summary powered by DJ 22

Conti.. Express Setup Screen powered by DJ 23

Wireless Troubleshooting Client Troubleshooting Most wireless issues are related to the client:  Verify that the wireless card is enabled: Most new laptops have a button or switch that disables the wireless card to save battery life.  Move to a “known good” region of the building: Do your testing in an area known to have a strong wireless signal. This may require using multiple wireless devices.  Verify that the client can identify the wireless network using the installed wireless utility: If you are unable to identify wireless SSID(s) in your vicinity, the client’s wireless card may be disabled, or the wireless access point may not be working. powered by DJ 24

Conti..  Ensure that the wireless client has the correct wireless security information and supports your security standards: You may need to re- enter the pre shared key to ensure that you entered it correctly. Likewise, the wireless card may not support the wireless security on your network. Try connecting to an SSID that does not use security from the wireless device. powered by DJ 25

Wireless Access Point Troubleshooting Most troubleshooting that deals with the wireless access point focuses on physical considerations:  Verify that the wireless access point is running the latest firmware version: Nothing is worse than spending hours on a problem that is related to a bug in the wireless firmware.  Test the wireless reception radius at different times of the day: Because of the varying degrees of interference that may occur over time, it is best to run multiple tests on your signal strength. You can do this simply and inexpensively by carrying around a laptop and observing the reception at differing locations. powered by DJ 26

Conti..  Verify your wireless channel configuration: If you have multiple wireless access points or are in an area where other access points may interfere, verify (using wireless software) the most saturated and unsaturated channels. For b/g, use channels 1, 6, or 11 in the U.S. For a, many more channels are available, and you should test for the cleanest frequency.  Consider the materials around and close to the access point: Try to avoid installing the access point near metal objects, which reflect the signal. Realize that a concrete block wall will absorb much more signal than a drywall barrier. powered by DJ 27

THANK YOU powered by DJ 28