CCNA Wireless Official Exam Certification Guide part 6 ppt

22 CCNA Wireless Official Exam Certification Guide 2. True or false: The U.S. complies with ETSI standards of EIRP. a. True b. False 3. What is the maximum EIRP for point-to-multipoint in Europe? (Choose all that apply.) a. 20 dBm b. 17 dBi c. 17 dBm d. 36 dBm 4. The FCC regulates EIRP in the U.S. to a maximum of _____ for point-to-point and _____ for point-to-multipoint. a. 36 dBm, 36 dBm b. 30 dBm, 17 dBm c. 17 dBm, 36, dBm d. 36 dBm, 17 dBm 5. The IEEE committees work on which of the following wireless standards? (Choose all that apply.) a. 802.11a b. 802.11g c. 802.11x d. 802.1q e. 802.11b 6. True or false: The IEEE is a regulatory body in the U.S. that controls the usage of wireless frequencies. a. True b. False 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 22 Chapter 2: Standards Bodies 23 7. In Europe, can a professional installer increase the gain on wireless antennas? a. Yes, provided that he or she decreases the transmit power using a 1:1 ratio. b. No; this is illegal. c. Only with a wavier. d. Antennas don’t have anything to do with gain. 8. The FCC regulates that professional installers maintain what ratio of gain to transmit power when increasing the gain of an antenna? a. 3:1 b. 1:1 c. 6:1 d. 1:3 9. Which organization certifies interoperability for wireless equipment? a. Wi-Max Alliance b. IEEE c. Wi-Fi Alliance d. FRF.12 10. Certification of wireless equipment includes which protocols and standards for inter- operability? (Choose two.) a. 802.11a/b/g b. IPsec c. WPA/WPA2 d. Zigbee 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 23 24 CCNA Wireless Official Exam Certification Guide Foundation Topics Wireless Standards and Regulatory Committees Many people benefit from the availability of wireless Internet access as they travel to vari- ous parts of the world. Without regulatory committees and organizations to ensure the proper use and interoperability of equipment, it’s likely that people could not connect from place to place. To ensure that certain rules governing the use of wireless RF are ad- hered to, numerous country-specific organizations and global committees monitor stan- dards and usage. This chapter discusses some of them. FCC The Federal Communications Commission (FCC) is an independent agency in the United States that regulates communication methods. It is held directly responsible by Congress. It is the FCC in the United States that governs the frequency ranges that can be used with- out a license, the transmit power of devices, the types of devices that can be used indoors as well as outdoors, and how the various types of hardware can be used. The FCC exists because of the Communications Act of 1934. Note: The FCC website is http://www.fcc.gov. When it comes to the FCC and Cisco wireless, it’s important to know the requirements de- fined in FCC - Part 15 - Antenna Requirements. This federal requirement states that an- tennas must use a unique nonstandard connector that cannot be acquired easily. The reason for not being acquired easily is to ensure that home users and noncertified in- stallers cannot easily deploy an antenna that goes beyond the regulated values. For this reason, Cisco uses a connector known as the Reverse-Polarity-Threaded Neil-Concelman (RP-TNC) connector, as shown in Figure 2-1. What makes this connector unique is that the center contacts are reversed so that you can’t use a store-bought antenna with a Cisco wireless device. If you did so, you might vi- olate the FCC regulatory requirements. Figure 2-1 RP-TNC Connector 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 24 Chapter 2: Standards Bodies 25 In addition to the antenna rules, the FCC defines power output rules that must be fol- lowed. There are rules for everyday people to follow, and rules for people who are consid- ered professionals in the field. A professional has a little more leeway than someone who buys a wireless device at the local electronics store. To get an idea of these rules, you can look at the 2.4-GHz EIRP Output Rules. Effective Isotropic Radiated Power (EIRP) is a way to measure the amount of energy radiated from an antenna. EIRP is an important con- cept to understand, especially when you’re dealing with regulatory bodies. It’s important that the EIRP not exceed that mandated by the governing bodies. These rules are de- signed for point-to-point scenarios as well as point-to-multipoint. The point-to-point rules are as follows: ■ You can have a maximum of 36-dBm EIRP. ■ You can have a maximum of 30-dBm transmitter power with 6-dBi gain of antenna and cable combined. ■ You are allowed a 1:1 ratio of power to gain. For point-to-multipoint scenarios, you are allowed the same maximum EIRP and the same maximum transmitter power and antenna gain; however, you can exceed the 36-dBm EIRP rule using a 3:1 ratio of power to gain. Table 2-2 compares the FCC maximum requirements for point-to-point to the Cisco maximum. Table 2-3 compares the FCC maximum requirements for point-to-multipoint to the Cisco maximum. ETSI The European Telecommunication Standards Institute (ETSI) is the not-for-profit organiza- tion that standardizes the frequencies and power levels used in Europe as well as many Table 2-2 FCC Antenna Requirements Versus Cisco Standards for Point-to-Point Environments Transmitter Power Maximum Gain EIRP FCC Maximum 30-dBm 6-dBm 36-dBm Cisco Maximum 20-dBm 36-dBm 56-dBm Table 2-3 FCC Antenna Requirements Versus Cisco Standards for Point-to-Multipoint Environments Transmitter Power Maximum Gain EIRP FCC Maximum 30-dBm 6-dBm 36-dBm Cisco Maximum 20-dBm 36-dBm 36-dBm Key Topi c Key Topi c 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 25 26 CCNA Wireless Official Exam Certification Guide other countries. The European Commission (EC) recognizes ETSI as an official European Standards Organization. Many of the mandates for wireless usage come from the EC. Then, ETSI defines various standards based on these mandates. According to the ETSI website, the ETSI has almost 700 members in 60 countries. Similar to the FCC, the ETSI has 2.4-GHz EIRP output rate standards that you should be familiar with. The ETSI’s rules, however, are different from the FCC’s rules. ETSI defines 20-dBm EIRP on point-to-multipoint and on point-to-point with 17-dBm maximum trans- mit power with 3-dBi gain. In a way, this is easier to remember, because these numbers are the same value for both point-to-point and point-to-multipoint connections. Of course, a professional installer can increase the gain as long as he or she lowers the transmit power below 17 dBm at a ratio of 1:1. Therefore, a professional installer could drop the transmit power by 1 dBm and increase the gain by 1 dBm and still stay within the guidelines. Table 2-4 compares the Cisco standards to the ETSI standards for EIRP. The table shows the governing body maximum transmitted power, maximum gain, and EIRP compared to that of the Cisco integated antennas. You can see that the Cisco antenna has a transmit power of 17 dBm and a maximum gain of 2.2 dBi and ends up with an EIRP of 19.2 dBm, which is lower than the 20 dBm allowed by the governing bodies. If you reduced the transmit power to 15 dBm and increased the maximum gain to 5 dBi, the resulting EIRP would be 20 dBm, which is still within the guidelines of the governing body. Likewise, re- ducing the transmit power to 13 dBm and increasing the gain to 7 dBi keeps the EIRP at 20 dBm—within the guidelines. Table 2-4 Cisco Versus ETSI EIRP Standards for Point-to-Point and Point-to-Multipoint Environments Transmitter Power (dBm) Maximum Gain (dBi) EIRP (dBm) Governing Body Maximum 17 3 20 Cisco Integrated Antennas 17 2.2 19.2 Reduced Tx Power 15 5 20 Reduced Tx Power 13 7 20 Reduced Tx Power 7 13 20 Reduced Tx Power 0 20 20 Key Topi c 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 26 Chapter 2: Standards Bodies 27 IEEE The Institute of Electrical and Electronics Engineers (IEEE) is a not-for-profit organization that has more than 370,000 members globally. It has 319 sections in ten geographic areas. It has defined more than 900 standards and has another 400 in development. Note: For a history of the IEEE, see http://ieee.org/web/aboutus/history/index.html. The IEEE’s “Wireless Standards Zone” is dedicated to standards that are related to wireless technology. Here you can find information about the 802 protocols, such as the following: ■ 802.11: The Working Group for Wireless LAN ■ 802.15: The Working Group for Wireless PAN ■ 802.16: The Working Group for Broadband Wireless Access Standards Note: You can find the Wireless Standards Zone at http://standards.ieee.org/wireless/ and an overview of the aforementioned working groups at http://standards.ieee.org/wireless/ overview.html. This book focuses mainly on the 802.11a, 802.11b, 802.11g, and 802.11n protocols. These protocols are for wireless LANs. Wi-Fi Certification Into the arena of interoperability testing enters the Wi-Fi Alliance. The Wi-Fi Alliance is a not-for-profit organization that certifies the interoperability of more than 4200 products. The Wi-Fi Alliance was formed in 1999 and currently has more than 300 members in more than 20 countries. What makes this organization different from the ETSI, FCC, and IEEE is that it gives its seal of approval to devices that plan in interoperability. The next time you’re at the electronics shop, flip over one of the wireless products; you might find it to be Wi-Fi Certified. If so, you will notice that the 802.11a, 802.11b, and 802.11g protocols are certified if the device can use them as well as security protocols such as WPA and WPA2. Usually, the label has a checkmark next to what the device is certified for. Note: The Wi-Fi alliance can be found at http://www.wi-fi.org. 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 27 28 CCNA Wireless Official Exam Certification Guide Table 2-5 Key Topics for Chapter 2 Key Topic Item Description Page Number Table 2-2 FCC antenna requirements versus Cisco stan- dards (point-to-point) 25 Table 2-3 FCC antenna requirements versus Cisco stan- dards (point-to-multipoint) 25 Table 2-4 Cisco versus ETSI EIRP standards (point-to- point and point-to-multipoint) 26 Exam Preparation Tasks Review All the Key Topics Review the most important topics from this chapter, denoted with the Key Topic icon. Table 2-5 lists these key topics and the page number where you can find each one. Complete the Tables and Lists from Memory Print a copy of Appendix B, “Memory Tables,” (found on the CD) or at least the section for this chapter, and complete the tables and lists from memory. Appendix C, “Memory Ta- bles Answer Key,” also on the CD, includes completed tables and lists to check your work. Definition of Key Terms Define the following key terms from this chapter, and check your answers in the glossary: FCC, IEEE, ETSI, W-Fi Alliance, EIRP 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 28 03_1587202115_ch02.qxd 9/29/08 2:46 PM Page 29 This chapter covers the following subjects: Characteristics of Wireless Networks: Provides a review of wireless transmissions. Influences on Wireless Transmissions: Covers the different elements that can affect wireless transmissions. Determining Signal Strength Influences: Describes how to determine your signal strength and what might be influencing your wireless deployment. 04_1587202115_ch03.qxd 9/29/08 2:42 PM Page 30 CHAPTER 3 WLAN RF Principles Table 3-1 “Do I Know This Already?” Section-to-Question Mapping Foundation Topics Section Questions Characteristics of Wireless Networks 1–3 Influences on Wireless Transmissions 4–9 Determining Signal Strength Influences 10–11 In wireless technologies, you need to understand what influences act on wireless transmis- sions. This chapter reviews the characteristics of wireless transmissions and the influences that act on them, sometimes causing problems. Some of the material covered in the first section, “Characteristics of Wireless Networks,” is a review of information you learned in Chapter 1, “Introduction to Wireless Networking Concepts.” If you are comfortable with your knowledge of this information, you can just review the key topics at the end of this chapter. The second section of this chapter covers influences on wireless transmissions. These are usually drawbacks, so you should become familiar with them. The third part of this chap- ter discusses ways to determine signal strength and other influences on wireless signals. You should do the “Do I Know This Already?” quiz first. If you score 80% or higher, you might want to skip to the section “Exam Preparation Tasks.” If you score below 80%, you should spend the time reviewing the entire chapter. Refer to Appendix A, “Answers to the ‘Do I Know This Already?’ Quizzes” to confirm your answers. “Do I Know This Already?” Quiz The “Do I Know This Already?” quiz helps you determine your level of knowledge of this chapter’s topics before you begin. Table 3-1 details the major topics discussed in this chap- ter and their corresponding quiz questions. 04_1587202115_ch03.qxd 9/29/08 2:42 PM Page 31 . Maximum 30-dBm 6- dBm 36- dBm Cisco Maximum 20-dBm 36- dBm 36- dBm Key Topi c Key Topi c 03_1587202115_ch02.qxd 9/29/08 2: 46 PM Page 25 26 CCNA Wireless Official Exam Certification Guide other countries 9/29/08 2: 46 PM Page 23 24 CCNA Wireless Official Exam Certification Guide Foundation Topics Wireless Standards and Regulatory Committees Many people benefit from the availability of wireless Internet. be found at http://www.wi-fi.org. 03_1587202115_ch02.qxd 9/29/08 2: 46 PM Page 27 28 CCNA Wireless Official Exam Certification Guide Table 2-5 Key Topics for Chapter 2 Key Topic Item Description