Data Communication Computer Network 简明教程

Data Communication & Computer Network

数据通信指的是在两台或多台计算机之间传输这种数字数据，而计算机网络或数据网络是允许计算机交换数据的电信网络。网络化计算机设备之间的物理连接通过有线媒体或无线媒体建立。最著名的计算机网络是 Internet。

Data communications refers to the transmission of this digital data between two or more computers and a computer network or data network is a telecommunications network that allows computers to exchange data. The physical connection between networked computing devices is established using either cable media or wireless media. The best-known computer network is the Internet.

本教程应教授你数据通信和计算机网络 (DCN) 的基础知识，还将带你了解与数据通信和计算机网络相关的各种高级概念。

This tutorial should teach you basics of Data Communication and Computer Network (DCN) and will also take you through various advance concepts related to Data Communication and Computer Network.

Why to Learn Data Communication & Computer Network?

Network Basic Understanding

将计算机与打印机等计算机化外围设备互连的系统称为计算机网络。计算机间的这种互连促进了它们之间的信息共享。计算机可以通过有线或无线媒体互相连接。

A system of interconnected computers and computerized peripherals such as printers is called computer network. This interconnection among computers facilitates information sharing among them. Computers may connect to each other by either wired or wireless media.

Network Engineering

网络工程是一项复杂的任务，涉及软件、固件、芯片级工程、硬件和电子脉冲。为了简化网络工程，整个网络概念被划分为多个层。每层涉及一些特定任务，且独立于所有其他层。但作为一个整体，几乎所有网络任务都依赖于这些层。层之间共享数据，它们彼此依赖才能接收输入并发送输出。

Networking engineering is a complicated task, which involves software, firmware, chip level engineering, hardware, and electric pulses. To ease network engineering, the whole networking concept is divided into multiple layers. Each layer is involved in some particular task and is independent of all other layers. But as a whole, almost all networking tasks depend on all of these layers. Layers share data between them and they depend on each other only to take input and send output.

Internet

网络的网络称为互联网络或简单地称为互联网。它是这个星球上存在的最大的网络。互联网广泛连接所有 WAN, 并可以连接到 LAN 和家庭网络。互联网使用 TCP/IP 协议套件, 并使用 IP 作为其寻址协议。现如今, 互联网广泛使用 IPv4 实现。由于地址空间短缺, 它正逐渐从 IPv4 迁移到 IPv6。

A network of networks is called an internetwork, or simply the internet. It is the largest network in existence on this planet.The internet hugely connects all WANs and it can have connection to LANs and Home networks. Internet uses TCP/IP protocol suite and uses IP as its addressing protocol. Present day, Internet is widely implemented using IPv4. Because of shortage of address spaces, it is gradually migrating from IPv4 to IPv6.

互联网使用户可以共享和访问全球范围内的海量信息。它使用万维网、FTP、电子邮件服务、音频和视频流等。在巨大的层面上，互联网使用客户端-服务端模型。

Internet enables its users to share and access enormous amount of information worldwide. It uses WWW, FTP, email services, audio and video streaming etc. At huge level, internet works on Client-Server model.

互联网采用速度极高的光纤骨干网。为了连接各种洲，将光纤铺设在海中，我们称之为海底通信电缆。

Internet uses very high speed backbone of fiber optics. To inter-connect various continents, fibers are laid under sea known to us as submarine communication cable.

Applications of Communication & Computer Network

计算机系统和外围设备连接起来形成网络。它们提供了许多优点：

Computer systems and peripherals are connected to form a network.They provide numerous advantages:

  1. Resource sharing such as printers and storage devices

  2. Exchange of information by means of e-Mails and FTP

  3. Information sharing by using Web or Internet

  4. Interaction with other users using dynamic web pages

  5. IP phones

  6. Video conferences

  7. Parallel computing

  8. Instant messaging

Audience

本教程是为计算机科学毕业生准备的，以帮助他们理解与数据通信和计算机网络相关的从基本到高级的概念。完成本教程后，你将发现自己在数据通信和计算机网络方面达到中等水平，你可以从此更上一层楼。

This tutorial has been prepared for the computer science graduates to help them understand the basic to advanced concepts related to Data Communication and Computer Networking. After completing this tutorial you will find yourself at a moderate level of expertise in Data Communication and Computer Networking from where you can take yourself to next levels.

Prerequisites

在你开始使用本教程之前，我假设你已经了解了基本的计算机概念，例如键盘、鼠标、显示器、输入、输出、主存和辅助存储器等。如果你不了解这些概念，我建议你阅读我们关于 Computer Fundamentals 的简短教程。

Before you start proceeding with this tutorial, I’m making an assumption that you are already aware about basic computer concepts like what is keyboard, mouse, monitor, input, output, primary memory and secondary memory etc. If you are not well aware of these concepts then I will suggest to go through our short tutorial on Computer Fundamentals.