计算机英语lesson 13

extensive popularity application layer characteristic architecture receipt legitimacy route logical perspective remote
adj.广大的，广阔的 n.普及，流行 n.应用 n.层, 阶层 n.特征，特性 n.建筑学，结构 n.收到；(pl)收入，证据，处方 n.合法性 n.路由，途径，渠道 adj.逻辑的，合理的 n.景色，观点，看法 adj.透视的 adj.远方的；【计】远程的
Unit 4 THE BRIFE INTRODUCTION TO THE INTERNET
Lesson 13
TCP/ IP
The data transmission on the web is going on according to protocols. The set of regulation used in the Internet is called TCP/IP. This is the abbreviation of first letters, meaning the Transmission Control Protocol and the Internet Protocol. It is a criterion, which defines that how the communication conducts between the computers. Maybe the computers are different and distant from each other. The TCP/IP protocol was born in the mid1970s. At that time, the United States Ministry of Defense wanted to develop a series of criterions for their wide web—APRANET. It seems that the TCP/IP protocol apparently includes only two protocols. In fact, it contains various kinds of protocols. The TCP and the IP protocols are two fundamental ones. The Internet is on the basement of this protocol. The extensive use of Internet results in the popularity of TCP/IP protocol.
Between the application and the network layers, the transport layer is a central piece of the layered network architecture. It provides the logical communications between applications running on different hosts. By logical communication, we mean that although the communicating application processes are not physically connected to each other by the real line, from the application’s perspective, it is as if they were physically connected. The application layer is faced to the common users. It supplies a group of usual applications, including remote access to computers, electronic mail, file transfers, chatting and so on. There are specific protocols for this layer, such as the HTTP, FTP, SMTP, and etc.
Notes
1.It seems that the TCP/IP protocol apparently includes only two protocols. 表面看来，似乎TCP/IP协议只包括两个协议。 （1）apparently：似乎，好像。 （2）注意这里的“It seems that...”句式，意思是“看起来似乎…”。 2.By logical communication, we mean that although the communicating application processes are not physically connected to each other by the real line, from the application’s perspective, it is as if they were physically connected. 逻辑通信的意思是尽管通信的应用程序之 间没有通过实际的线路物理相连，但是从应用程序的角度看， 它们好像已经物理相连了。 （1）from one’s perspective：从…的角度看。 （transmission 转播 regulation criterion define conduct defence apparently basement 基层, 基脚 n.播送, 发射, 传动, 传送, 传输, n.规则, 规章, 调节, 校准 n.标准 vt.定义, 详细说明 n.行为, 操行 n. , v.引导,管理,为人,传导 n. & vt.防御 adv.显然地 n.建筑物的底部底层, 地窖,基岩,
According to this protocol, the network is divided into four layers: the application layer, the transport layer, the network layer and the network access layer. Every layer has its own function and characteristic. The network access layer is the lowest layer of the whole architecture. This layer is responsible for the receipt and the send of data. It is composed of two layers, which are the data link layer and physical layer. The network layer’s main protocol is the IP protocol. This layer’s job is to check the legitimacy of the data, to find the best route for the data and so on.
Computer Terms
ROM：Read Only Memory，只读存储器。 IT：Information Technology，信息技术。 FTP：File Transfer Protocol，文件传送协议。 ISP：Internet Service Provider，因特网服务提供者。 DNS：Domain Name System，域名系统。 IEEE：Institute of Electrical and Electronic Engineers，电机及电 子学工程师联合会。 ASCII：American Standard Code for Information Interchange，美 国信息交换标准代码。