This chapter covers the following subjects:
Wireless LAN Concepts: This section explains the basic theory behind transmitting data with radio waves using wireless LAN standards.
Deploying WLANs: This section lists a set of generic steps for installing small WLANs, with no product-specific details.
Wireless LAN Security: This section explains the various WLAN security options that have progressed through the years.
So far, this book has dedicated a lot of attention to (wired) Ethernet LANs. Although they are vitally important, another style of LAN, wireless LANs (WLAN), fills a particularly important role in providing network access to end users. In particular, WLANs allow the user to communicate over the network without requiring any cables, enabling mobile devices while removing the expense and effort involved in running cables. This chapter examines the basic concepts, standards, installation, and security options for some of the most common WLAN technologies today.
As a reminder if you're following the optional reading plan listed in the Introduction to this book, you will be moving on to Chapter 1 of the CCNA ICND2 Official Exam Certification Guide following this chapter.
"Do I Know This Already?" Quiz
The "Do I Know This Already?" quiz allows you to assess whether you should read the entire chapter. If you miss no more than one of these nine self-assessment questions, you might want to move ahead to the "Exam Preparation Tasks" section. Table 11-1 lists the major headings in this chapter and the "Do I Know This Already?" quiz questions covering the material in those sections. This helps you assess your knowledge of these specific areas. The answers to the "Do I Know This Already?" quiz appear in Appendix A.
Table 11-1. "Do I Know This Already?" Foundation Topics Section-to-Question Mapping
Foundation Topics Section
Wireless LAN Concepts
Wireless LAN Security
Which of the following IEEE wireless LAN standards uses only the U-NII band of frequencies (around 5.4 GHz)?
Which of the following answers is the correct maximum speed at which two IEEE WLAN devices can send data with a particular standard?
- 802.11b, using OFDM, at 54 Mbps
- 802.11g, using OFDM, at 54 Mbps
- 802.11a, using DSSS, at 54 Mbps
- 802.11a, using DSSS, at 11 Mbps
Which of the following lists the nonoverlapping channels when using 802.1b DSSS in the U.S.?
- 1, 2, 3
- 1, 5, 9
- 1, 6, 11
- a, b, g
- 22, 33, 44
Which of the following terms refers to a WLAN mode that allows a laptop to roam between different access points?
- None of the other answers are correct.
When configuring a wireless access point, which of the following are typical configuration choices?
- The speed to use
- The wireless standard to use
- The size of the desired coverage area
Which of the following is true about an ESS's connections to the wired Ethernet LAN?
- The AP connects to the Ethernet switch using a crossover cable.
- The various APs in the same WLAN need to be assigned to the same VLAN by the Ethernet switches.
- The APs must have an IP address configured to forward traffic.
- The APs using mixed 802.11g mode must connect via a Fast Ethernet or faster connection to an Ethernet switch.
Which of the following are not common reasons why a newly installed WLAN does not allow a client to connect through the WLAN into the wired infrastructure?
- The AP is installed on top of a metal filing cabinet.
- The client is near a fast-food restaurant's microwave oven.
- The client is sitting on top of a big bundle of currently used Cat5 Ethernet cables.
- The AP was configured to use DSSS channel 1 instead of the default channel 6, and no one configured the client to use channel 6.
Which of the following WLAN security standards refer to the IEEE standard?
Which of the following security features were not in the original WEP security standard but are now in the WPA2 security standard?
- Dynamic key exchange
- Preshared Keys (PSK)
- 802.1x authentication
- AES encryption