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cwna certified wireless network administrator official study guide phần 7

Bộ khuếch đại RF phải được kiểm định mỗi năm một lần để đảm bảo độ chính xác và hiệu suất tiếp tục.Bộ khuếch đại RF được sử dụng với mạng LAN không dây được cài đặt trong loạt với các đường dẫn tín hiệu chính như dưới đây trong hình 5,21. | MAC and Physical Layers CHAPTER 8 CWNA Exam Objectives Covered Understand and apply the following concepts surrounding wireless LAN Frames The difference between wireless LAN and Ethernet frames Layer 3 Protocols supported by wireless LANs Specify the modes of operation involved in the movement of data traffic across wireless LANs Distributed Coordination Function DCF Point Coordination Function PCF CSMA CA vs. CSMA CD Interframe spacing RTS CTS Dynamic Rate Selection Modulation and coding In This Chapter How wireless LANs communicate Interframe Spacing RTS CTS Process Modulation CWNA Study Guide Copyright 2002 Planet3 Wireless Inc. Chapter 8 - MAC and Physical Layers 202 We mentioned earlier in this book how most of the technology in any wireless LAN is the same but that manufacturers approach and utilize that technology differently. In this chapter we will discuss some of the MAC and Physical layer characteristics of wireless LANs that are common to all wireless LAN products regardless of manufacturer. We will explain the difference between Ethernet and wireless LAN frames and how wireless LANs avoid collisions. We ll walk through how wireless LAN stations communicate with one another under normal circumstances then how collision handling occurs in a wireless LAN. It is important for you as a wireless LAN administrator to know this level of detail in order to be able to properly configure and administer an access point as well as to be able to diagnose and solve problems that are common to wireless LANs. How Wireless LANs Communicate In order to understand how to configure and manage a wireless LAN the administrator must understand communication parameters that are configurable on the equipment and how to implement those parameters. In order to estimate throughput across wireless LANs one must understand the affects of these parameters and collision handling on system throughput. This section conveys a basic understanding of many configurable parameters and their