18 Wireless LAN fundamentals

 

This chapter covers

  • The challenges of using air as a communication medium
  • The characteristics of radio frequency
  • Wireless LAN standards as defined by IEEE 802.11
  • Connecting wireless devices using different kinds of service sets

It’s time to break our communications out of their wired constraints and explore a new medium for communication: air. Just as copper twisted-pair and glass fiber-optic cables provide a medium to transmit encoded messages using electricity and light, the air all around us (or, more precisely, the space around us that happens to be filled with air) provides an alternative medium to transmit messages using electromagnetic waves.

In this chapter and the three that follow it, we will cover various aspects of wireless LANs as defined by IEEE 802.11—better known as Wi-Fi. This chapter starts by covering the foundational concepts of wireless LANs and how devices communicate with radio frequency waves. We will cover the following CCNA exam topics:

  • 1.1 Explain the role and function of network components
    • 1.1.d Access points
  • 1.11 Describe wireless principles

18.1 Wireless communications

18.1.1 The challenges of wireless communications

18.1.2 Wave behaviors

18.2 Radio frequency

18.2.1 Amplitude and frequency

18.2.2 RF bands and channels

18.2.3 IEEE 802.11 standards

18.3 Service sets

18.3.1 Independent basic service set

18.3.2 Basic service set

18.3.3 Extended service set

18.3.4 Mesh basic service set

18.4 Additional AP operational modes

18.4.1 Repeater

18.4.2 Workgroup bridge

18.4.3 Outdoor bridge

Summary