Click to edit Master subtitle style Chapter 12: Wireless Networkimg Instructor:

Chapter 12 Objectives The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: 3.3 Compare and contrast different wireless standards. – a/b/g/n standards –Distance – Speed – Latency –Frequency – Channels – MIMO – Channel bonding 3.7 Compare and contrast different LAN technologies. – Properties: – CSMA/CA 2

Chapter 12 Objectives (Cont) The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: 2.2 Given a scenario, install and configure a wireless network. WAP placement Antenna types Interference Frequencies Channels Wireless standards SSID (enable/disable) Compatibility ( a/b/g/n) 3

Chapter 12 Objectives (Cont) The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: 5.1 Given a scenario, implement appropriate wireless security measures. Encryption protocols: WEP WPA WPA2 WPA Enterprise MAC address filtering Device placement Signal strength 4

Wireless Technologies 5 Sipping coffee at a café or hanging out in an airport until they finally fix the plane you’re waiting to board no longer requires reading actual papers and magazines to avoid numbing boredom and kill time. Now, you can just connect to the local wireless network and catch up on your s, blog, do a little gaming. The basic wireless LANs (WLANs) most commonly used today are similar to 10BaseT Ethernet with hubs. –Typically run half-duplex communication. –Everyone is sharing the same bandwidth. –Only one user is communicating at a time.

Wireless Agencies and Standards WLANs transmit over radio frequencies, they’re regulated by the same types of laws used to govern things like AM/FM radios. In the United States, it’s the Federal Communications Commission (FCC) that regulates the use of wireless LAN devices Institute of Electrical and Electronics Engineers (IEEE) takes it from there and creates standards based on what frequencies the FCC releases for public use. 6

Frequencies Ranges The FCC has released three unlicensed bands for public use: 900MHz, 2.4GHz, and 5GHz. –The 900MHz and 2.4GHz bands are referred to as the Industrial, Scientific, and Medical (ISM) bands. –The 5GHz band is known as the Unlicensed National Information Infrastructure (UNII) band 7

Wireless LAN History Use of the ISM band started in early The ISM band is deployed today in multiple environments, including outdoor links, mesh networks, office buildings, healthcare, warehousing, and homes. 8

Committees and Subcommittees IEEE was the first, original standardized WLAN at 1 and 2Mbps ratified in

802.11b – 2.4gHz The problem with b lies in how the Data Link layer is dealt with. In order to solve problems in the RF spectrum, a type of Ethernet collision detection was created called Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). 10 CSMA/CA also has an optional implementation called Request to Send, Clear to Send (RTS/CTS) For every packet sent, an RTS/CTS acknowledgment must be received.

802.11g The g standard was ratified in June 2003 and is backward compatible to b g delivers 54Mbps maximum data rate g operates in the 2.4GHz range (the same as b). 11 There are 14 different channels (each 22Mhz wide) 2.4GHz range. Only 11 channels are configurable in the U.S. Channels 1, 6, and 11 are non-overlapping. Three access points can be in the same area without experiencing interference.

802.11a The IEEE ratified the a standard in 1999, but the first a products didn’t begin appearing on the market until late a delivers a maximum data rate of 54Mbps a provides 12 non-overlapping frequency channels a uses the UNII bands. 12

802.11h The FCC added 11 new channels in February 2004 and 2008 we get to begin using these channels based on releases a 5GHz products. This means that we gain access to up to 23 non-overlapping channels. And there are even two new features to the 5GHz radio that are part of the h specification: –Dynamic Frequency Selection (DFS) –Transmit Power Control (TPC) 13

802.11n n builds on previous standards by adding Multiple-Input Multiple-Output (MIMO), which employs multiple transmitters and receiver antennas to increase data throughput n can have up to eight antennas, but most of today’s access points use four n uses smart antennas; if you did have four of them, two would be used for transmitting simultaneously with the other two receiving simultaneously. Smart Antennas allow for much higher data rates than a/b/g, some claim it will provide about 250Mbps. 14

Comparing Standards It’s interesting to see the evolution over the years each standard was ratified, the frequency of each, the number of non-over lapping channels, the physical layer transmission technique and the data rates for each of the IEEE standards in use today. 15

Wireless LAN Modulation Techniques Direct-Sequence Spread-Spectrum (DSSS) –The modulation techniques specified by the original IEEE standard –The standard used for the IEEE b standard. IEEE b uses Differential Binary Phase Shift Keying (DBPSK) for 1Mbps DSSS IEEE b and Differential Quadrature Phase Shift Keying (DQPSK) for 2Mbps DSSS. Frequency-Hopping Spread Spectrum (FHSS) –Original modulation technique specified by the IEEE standard. –Isn’t the technique of choice for vendors of Orthogonal Frequency Division Multiplexing (OFDM) –802.11a/g uses OFDM with a system of 52 carriers (sometimes referred to as subcarriers) –Modulated by BPSK or QPSK. –OFDM’s spread-spectrum technique distributes the data over these 52 carriers 16

Range Comparisons The range comparisons show of each standard and shows these different ranges using an indoor open-office environment as a factor (using default power settings). 17

Wireless Access Points Wireless networks have a component connecting all wireless devices together, the device is known as a wireless access point (WAP), or just AP. Wireless access points have at least one antenna (sometimes two for better reception—called diversity) and a port to connect them to a wired network. 18

Wireless Network Interface Card (Wireless NIC) A wireless NIC does the same job as a traditional NIC; but instead of having a socket to plug some cable into, the wireless NIC has a radio antenna. 19

Wireless Networks In ad-hoc mode, the wireless devices communicate directly without the need for an AP. An example of this is two laptops with wireless NICs installed. If both cards were set up to operate in ad-hoc mode, they could connect and transfer files as long as the other network settings, like protocols, were set up to enable this as well. –This is an independent basic service set (IBSS) 20 Ad-Hoc Mode: Independent Basic Service Set (IBSS)

Wireless Networks The most common use of wireless networking equipment is to give us the wireless equivalent of a wired network wireless equipment has the ability to operate in what’s known as infrastructure mode wireless equipment can operate with one access point providing communication for multiple wireless devices. –This is a basic service set (BSS) 21 Infrastructure Mode: Basic Service Set (BSS)

Wireless Networks Set multiple access points to the same SSI and mobile wireless clients can roam around freely within the same network. This creates an Extended Service Set ( ESS)) and provides more coverage then a single access point. For users to be able to roam throughout the wireless network from AP to AP without losing their connection to the network, all APs must overlap by at least 10% of their signal. 22 Infrastructure Mode: Extended Service Set (ESS)

Installing and Configuring Hardware Installing equipment is actually fairly simple Two main types of components in networks: APs –The AP is fairly simple; take it out of the box, connect the antenna(e) if necessary, connect the power, and then place the AP where it can reach the highest number of clients. –Walls obstruct the signal means putting the AP out in the open—even indoors—works better. –The AP should be placed away from sources of RF interference (putting it next to the microwave or phone system is really bad idea) NICs –Wireless NIC installation is just like installing any other network card; but today, most, laptops have wireless cards preinstalled, and that’s as easy as it gets! Just like connecting an Ethernet card to a LAN switch, you need the wireless network card to connect to an access point. 23

NIC Configuration – Wireless Both Windows XP and Vista (as well as Server 2003/2008) include software to automatically configure a wireless connection, and they do so automatically when you install a wireless NIC. 24 Windows XP wireless configuration screen

NIC Configuration - Encryption In addition to the general configuration, you may have to configure the encryption for the connection (if the wireless connection you are using requires it). To set up how your workstation uses encryption for a particular connection click the SSID of the wireless network you want to configure in the “Wireless Network Connection” dialog box and then click “Configure”. 25 Configuring encryption

NIC Configuration Windows 7 26

AP Configuration There are literally hundreds of different APs out there, and of course, each uses a different method to configure its internal software. The good news is that for the most part, they all follow the same general patterns. 27

Wireless Security War Driving Open Access Service Set Identifiers (SSIDs) Wired Equivalent Privacy (WEP) Media Access Control (MAC) Address Authentication Remote Authentication Dial In User Service (RADIUS) Temporal Key Integrity Protocol (TKIP) Wi-Fi Protected Access (WPA) or WPA 2 Pre-Shared Key 28

Summary 29 Summary Exam Essentials Section Written Labs Review Questions