Chapter 1 Introduction_homework1

Chapter 1 Introduction 第一章概述作业

Page 22-25

Question 1

Identify the five components of a data communication system. 给出一个数据通信系统的五个组成部分

ANSWER:

Five components of data communication:

Message, Sender, Receiver, Medium, Protocol

Question 18 Single Choice

Which topology requires a central controller or hub? 下列哪种拓扑结构需要一个中心控制器或集线器？

A. Mesh网状网 B. Star星型 C. Bus总线型 D. Ring环型

ANSWER:

B, 需要一个集线器

Question 28 Exercises

Assume six devices are arranged in a mesh topology. How many cables are needed? How many ports are needed for each device? 假设有六台设备按网状网拓扑连接在一起。问需要多少根连接电缆？每台设备需要多少个端口？

ANSWER:

N = 6 (number of devices)

number of cables = $\frac{N(N-1)}{2}=\frac{6\ast 5}{2}=15$

number of ports (for each device) = $N-1$ =5