1.switch交换机

Router路由器

Component组件

TCP传输控制协议

IP万维网

WWW入侵检测和防御系统

HTTP超文本传输控制协议

E-mail电子邮件

FTP文件传输协议

Firewall防火墙

IDS入侵检测系统

Network Safety网络安全

OSI开放系统互联

2.A LAN is used for communications in a small community in which resources,such as (printers),software,and servers,are shard.Each device connected to a LAN has a unique(address).Two or more LANs of the same type can also be connected to (forward)are additional headers appended for local routing.These new-looking packets are known as (packets)

3.(1)The internet is a global system of interoconnected computer networks that use the standard internet protocol suite (TCP/IP)to serve billions of users worldwide.

因特网是一个由，相互连接的计算机网络组成的全球系统，它使用标准的因特网协议套件(TCP/IP)为全世界数10亿用户提供服务。

(2)As with most application-layer protocols ,SMTP has two sides a client side,which execures on the sender's mail server and a server,and a server side,which executes on the recipient's mail server.

与大多数应用层协议一样，SMTP有两个方面客户端，其中在发件人的邮件服务器上重复服务器端在收件人的邮件ERC上执行包。

(3)In the ster topology,all users are directly connected to a central user through two unidirectional links:one for uplink and the other for downlink.

在星型拓扑中，所有用户通过两条单向链路直接连接到一个。中新用户一条用于上行，另一条用于下行

(4)A compiter network is a group of computers that are connected to each other for the purpose of communication.

计算机网络是一组为了目的或通信而相互连接的计算机。

(5)WANs are used to connect LANs and other types of networks together,so that users and computers in one location can communicate with users and computers in other locations.

广域网用于将局域网和其他类型的网络连接在一起，以便一个未知的用户和计算机可以与其他位置的用户和计算机通信。