Internet Technologies 简明教程

Internet Connectivity

在本教程中，我们将讨论如何连接到互联网，即互联网服务提供商、软件和硬件要求、配置互联网连接等。

Here in this tutorial, we will discuss how to connect to internet i.e. internet service providers, software and hardware requirements, configuring internet connection etc.

Internet Service Providers (ISP)

@ {s3} 是一家提供互联网接入的公司。他们提供各种服务：

Internet Service Provider (ISP) is a company offering access to internet. They offer various services:

  1. Internet Access

  2. Domain name registration

  3. Dial-up access

  4. Leased line access

ISP Types

ISP 可大致分为六类，如下图所示：

ISPs can broadly be classified into six categories as shown in the following diagram:

internet isp

它们通过电话线、有线 Wi-Fi 或光纤提供互联网接入。

They provide access to internet through telephone lines, cable wi-fi or fiber optics.

此类提供商提供邮箱托管服务。

Such providers offer mailbox hosting services.

托管 ISP 提供电子邮件和其他 Web 托管服务，如虚拟机、云等。

Hosting ISPs offers e-mail, and other web hosting services such as virtual machines, clouds etc.

此类 ISP 通过其他 ISP 服务提供互联网接入。

Such ISPs offer internet access via other ISP services.

免费 ISP 不收取互联网服务费用。

Free ISPs do not charge for internet services.

Connection Types

有几种方法可以连接到互联网。以下是这些可用的连接类型：

There exist several ways to connect to the internet. Following are these connection types available:

Dial-up Connection

Dial-up 连接使用电话线将 PC 连接到互联网。它需要一个调制解调器来设置拨号连接。这个调制解调器充当 PC 和电话线之间的接口。

Dial-up connection uses telephone line to connect PC to the internet. It requires a modem to setup dial-up connection. This modem works as an interface between PC and the telephone line.

还有一个通信程序，指示调制解调器拨打 ISP 提供的特定号码。

There is also a communication program that instructs the modem to make a call to specific number provided by an ISP.

拨号连接使用以下两个协议之一：

Dial-up connection uses either of the following protocols:

下图显示了使用调制解调器访问互联网：

The following diagram shows the accessing internet using modem:

internet internet access using modem

ISDN

ISDN 是 Integrated Services Digital Network. 的缩写。它使用承载数字信号（而非模拟信号）的电话线建立连接。

ISDN is acronym of Integrated Services Digital Network. It establishes the connection using the phone lines which carry digital signals instead of analog signals.

有两种技术可提供 ISDN 服务：

There are two techniques to deliver ISDN services:

Key points:

Key points:

  1. The BRI ISDN consists of three distinct channels on a single ISDN line: t1o 64kbps B (Bearer) channel and one 16kbps D (Delta or Data) channels.

  2. The PRI ISDN consists of 23 B channels and one D channels with both have operating capacity of 64kbps individually making a total transmission rate of 1.54Mbps.

下图显示了使用 ISDN 连接访问互联网：

The following diagram shows accessing internet using ISDN connection:

internet internet access using isdn connection

DSL

DSL 是 Digital Subscriber Line. 的缩写。它是一种宽带连接形式，因为它通过普通电话线提供连接。

DSL is acronym of Digital Subscriber Line. It is a form of broadband connection as it provides connection over ordinary telephone lines.

以下是一些今天可用的 DSL 技术版本：

Following are the several versions of DSL technique available today:

上面提到的所有技术与其上传和下载速度、比特传输速率和服务水平不同。

All of the above mentioned technologies differ in their upload and download speed, bit transfer rate and level of service.

下图显示了我们如何利用 DSL 技术连接到互联网：

The following diagram shows that how we can connect to internet using DSL technology:

internet internet access using dsl modem

Cable TV Internet Connection

有线电视互联网连接是通过有线电视线路提供的。它使用同轴电缆，该电缆能够以比普通电话线快得多的速度传输数据。

Cable TV Internet connection is provided through Cable TV lines. It uses coaxial cable which is capable of transferring data at much higher speed than common telephone line.

Key Points:

Key Points:

  1. A cable modem is used to access this service, provided by the cable operator.

  2. The Cable modem comprises of two connections: one for internet service and other for Cable TV signals.

  3. Since Cable TV internet connections share a set amount of bandwidth with a group of customers, therefore, data transfer rate also depends on number of customers using the internet at the same time.

下图展示了如何使用有线电视连接接入互联网：

The following diagram shows that how internet is accessed using Cable TV connection:

internet internet access using cable tv connection

Satellite Internet Connection

卫星互联网连接提供高速互联网连接。卫星网络连接有两种类型：单向连接或双向连接。

Satellite Internet connection offers high speed connection to the internet. There are two types of satellite internet connection: one way connection or two way connection.

单向连接中，我们只能下载数据，但如果我们想上传，我们就需要通过电话线通过 ISP 拨号连接。

In one way connection, we can only download data but if we want to upload, we need a dialup access through ISP over telephone line.

双向连接中，我们可以下载和上传数据，由卫星提供。它不需要任何拨号连接。

In two way connection, we can download and upload the data by the satellite. It does not require any dialup connection.

下图展示了如何使用卫星互联网连接接入互联网：

The following diagram shows how internet is accessed using satellite internet connection:

internet internet access using satellite connection

Wireless Internet Connection

无线互联网连接利用无线电频段连接互联网，并提供非常高的速度。无线互联网连接可以通过 WiFi 或蓝牙获得。

Wireless Internet Connection makes use of radio frequency bands to connect to the internet and offers a very high speed. The wireless internet connection can be obtained by either WiFi or Bluetooth.

Key Points:

Key Points:

  1. Wi Fi wireless technology is based on IEEE 802.11 standards which allow the electronic device to connect to the internet.

  2. Bluetooth wireless technology makes use of short-wavelength radio waves and helps to create personal area network (PAN).