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Wireless Networks: Implementation, Configuration, and Troubleshooting

Learn about different wireless network implementations, wireless LAN infrastructure setup, network hardening techniques, and common troubleshooting issues. Explore the various wireless standards and technologies used in wireless communication.

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Wireless Networks: Implementation, Configuration, and Troubleshooting

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  1. Click to edit Master subtitle style Chapter 12: Wireless Networkimg

  2. Chapter 12 Objectives The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: 1.7 Differentiate between network infrastructure implementations WLAN o Hotspot PAN o Bluetooth o IR o NFC (near field communication) 2.7 Install and configure wireless LAN infrastructure and implement the appropriate technologies in support of wireless capable devices Small office/home office wireless router Wireless access points o Device density o Roaming o Wireless controllers VLAN pooling LWAPP 2

  3. Chapter 12 Objectives(Cont) The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: Wireless bridge Site surveys o Heat maps Frequencies o 2.4 Ghz o 5.0 Ghz Channels Goodput Connection types o 802.11a-ht o 802.11g-ht Antenna placement Antenna types o Omnidirectional o Unidirectional MIMO/MUMIMO Signal strength o Coverage o Differences between device antennas SSID broadcast Topologies o Adhoc o Mesh o Infrastructure Mobile devices o Cell phones o Laptops o Tablets o Gaming devices o Media devices 3

  4. Chapter 12 Objectives(Cont) The Following CompTIA Network+ Exam Objectives Are Covered in This Chapter: 3.3 Given a scenario, implement network hardening techniques Wireless security o WEP o WPA/WPA2 Enterprise Personal o TKIP/AES o 802.1x o TLS/TTLS o MAC filtering 4.3 Given a scenario, troubleshoot and resolve common wireless issues Open networks Rogue access point MIMO AP placement AP configurations o LWAPP o Thin vs thick 5.3 Given a scenario, deploy the appropriate wireless standard 802.11a 802.11b 802.11g 802.11n 802.11ac 4

  5. Wireless Technologies • 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 emails, 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. 5

  6. 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

  7. 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

  8. Wireless LAN History • Use of the ISM band started in early 1990. • The ISM band is deployed today in multiple environments, including outdoor links, mesh networks, office buildings, healthcare, warehousing, and homes. 8

  9. 802.11 Committees and Subcommittees • IEEE 802.11 was the first, original standardized WLAN at 1 and 2Mbps ratified in 1997. 9

  10. 802.11b – 2.4gHz • The problem with 802.11b 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). • 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. 10

  11. 802.11g • The 802.11g standard was ratified in June 2003 and is backward compatible to 802.11b. • 802.11g delivers 54Mbps maximum data rate • 802.11g operates in the 2.4GHz range (the same as 802.11b). • 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. 11

  12. 802.11a • The IEEE ratified the 802.11a standard in 1999, but the first 802.11a products didn’t begin appearing on the market until late 2001. • 802.11a delivers a maximum data rate of 54Mbps • 802.11a provides 12 non-overlapping frequency channels. • 802.11a uses the UNII bands. 12

  13. 802.11h • The FCC added 11 new channels in February 2004 and 2008 we get to begin using these channels based on releases 802.11a 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 802.11h specification: • Dynamic Frequency Selection (DFS) • Transmit Power Control (TPC) 13

  14. 802.11n • 802.11n builds on previous 802.11 standards by adding Multiple-Input Multiple-Output (MIMO), which employs multiple transmitters and receiver antennas to increase data throughput. • 802.11n can have up to eight antennas, but most of today’s access points use four. • 802.11n 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 802.11a/b/g, some claim it will provide about 250Mbps. 14

  15. Wireless LAN Modulation Techniques • Direct-Sequence Spread-Spectrum (DSSS) • The modulation techniques specified by the original IEEE 802.11 standard • The standard used for the IEEE 802.11b standard. • IEEE 802.11b uses Differential Binary Phase Shift Keying (DBPSK) for 1Mbps DSSS • IEEE 802.11b and Differential Quadrature Phase Shift Keying (DQPSK) for 2Mbps DSSS. • Frequency-Hopping Spread Spectrum (FHSS) • Original modulation technique specified by the IEEE 802.11 standard. • Isn’t the technique of choice for vendors of 802.11 • 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 15

  16. Comparing 802.11 Standards 802.11ac 2013 5Ghz Varies OFDM 1000+ 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. 16

  17. Range Comparisons 11Mbps 5.5Mbps 802.11b 2Mbps 1Mbps 54Mbps 48Mbps 36Mbps 24Mbps 802.11g 18Mbps 12Mbps 9Mbps 6Mbps 54Mbps 48Mbps 36Mbps 802.11a 24Mbps 18Mbps 12Mbps 9Mbps 6Mbps 50 ft. 150 ft. 200 ft. 250 ft. 300 ft. 100 ft. 350 ft. The range comparisons show of each 802.11 standard and shows these different ranges using an indoor open-office environment as a factor (using default power settings). 17

  18. 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

  19. 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

  20. Wireless Networks Ad-Hoc Mode: Independent Basic Service Set (IBSS) • 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

  21. Wireless Networks Infrastructure Mode: Basic Service Set (BSS) DS* Access point Internet Wireless clients *DS=Distribution System 21

  22. Wireless Networks Infrastructure Mode: Extended Service Set (ESS) “Wireless Cell” “Wireless Cell” Channel 6 Channel 1 LAN Backbone Overlapping 20% SSID Sales SSID Sales Wireless clients Wireless clients 22

  23. Standalone and controller based NetworksFigure 12.13

  24. Figure 12:14 LWAPP

  25. Figure 12:15 Mobile Hotspot

  26. Figure 12:16 iPhone Hotspot

  27. Installing and Configuring Hardware Installing 802.11 equipment is actually fairly simple Two main types of components in 802.11 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. 27

  28. NIC Configuration – Wireless Windows includes software to automatically configure a wireless connection, and it does so automatically when you install a wireless NIC. 28

  29. NIC Configuration - Encryption Configuring 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”. 29

  30. NIC Configuration Windows 7 30

  31. 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. 31

  32. 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 32

  33. Figure 12:17 Basic coverage LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP

  34. Figure 12:18 Enterprise design LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP

  35. Figure 12:19 multiple floors LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP LWAPP Channel 1 Channel 11 2nd Floor Channel 6 Channel 1 Channel 6 Channel 1 1st Floor Channel 1 Channel 11

  36. Figure 12:20 heatmap

  37. Chapter 12 RADIUS authentication serverFigure 12.21 802.1x Traffic Only Access point acts as authenticator EAP plug-in goes In RADIUS server Operates on a client

  38. Chapter 12 AP configurationGraphic c12uf007.tif

  39. Summary Summary Exam Essentials Section Written Labs Review Questions 39

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