Transcript Internet Basics Section 8a This lesson includes the following sections

Section 8a
Internet Basics
This lesson includes the following sections:
• How the Internet Works
• Major Features of the Internet
• Online Services
• Internet Features in Application Programs
How the Internet Works
•
TCP/IP: The Universal Language of the Internet
•
Routing Traffic Across the Internet
•
Addressing Schemes
•
Domains and Subdomains
How the Internet Works - TCP/IP
•
Every computer and network on the Internet uses
the same protocols (rules and procedures) to control
timing and data format.
•
The protocol used by the Internet is the
Transmission Control Protocol/Internet Protocol, or
TCP/IP.
•
No matter what type of computer system you
connect to the Internet, if it uses TCP/IP, it can
exchange data with any other type of computer.
How the Internet Works Routing Traffic Across the Internet
•
Most computers don't connect directly to the Internet.
Instead, they connect to a smaller network that is
connected to the Internet backbone.
•
The Internet includes thousands of host computers
(servers), which provide data and services as
requested by client systems.
•
When you use the Internet, your PC (a client)
requests data from a host system. The request and
data are broken into packets and travel across
multiple networks before being reassembled at their
destination.
How the Internet Works Routing Traffic Across the Internet (Cont.)
•
Suppose that you request data from a server
•Your request must be broken into packets
•The packets are routed through your local network,
and possibly through one or more subsequent
networks, to the internet backbone
•After leaving the backbone, the packets are then
routed through one or more networks until they reach
the appropriate server and are reassembled into the
complete request
•Once the destination server receives your request, it
begins sending you the requested data.
How the Internet Works Addressing Schemes
•
In order to communicate across the Internet, a
computer must have a unique address.
•
Every computer on the Internet has a unique
numeric identifier, called an Internet Protocol (IP)
address.
•
Each IP address has four parts – each part a number
between 0 and 255. An IP address might look like
this: 205.46.117.104.
How the Internet Works Domains and Subdomains
•
In addition to an IP address, most Internet hosts or
servers have a Domain Name System (DNS) address,
which uses words.
• A domain name identifies the type of institution that
owns the computer. An Internet server owned by IBM
might have the domain name ibm.com.
•
Some enterprises have multiple servers, and identify
them with subdomains, such as products.ibm.com.
• Outside the United States, domains usually identify the
country in which the system is located, such as .ca
(Canada), .fr (France)
網際網路領域
新的頂層領域名稱
正在考慮中頂層領域名稱
Major Features of the Internet
•
The World Wide Web
•
E-Mail
•
News
•
Telnet
•
File Transfer Protocol (FTP)
•
Internet Relay Chat (IRC)
Major Features of the Internet The World Wide Web
•
Internet Service Provider: Hinet, Seednet…
•
World Wide Web (the Web or WWW) was created in
1989 in Switzerland as a method to create hypertext
document.
•
A hypertext document is a specially encoded file that
uses the hypertext markup language (HTML).
•
This language allow users to embed hypertext links
(hyperlinks or links) in the document.
•
A collection of related Web pages is called Web site,
which are housed on Web servers.
Major Features of the Internet Web Browsers and HTML Tags
•
Copying a page onto a server is called posting
(publishing or uploading) the page.
•
The Web is not popular until 1993, when Mosaic, a
point-and-click Web browser (or browser), was
developed.
•
To format a document, a designer places HTML tags (<>)
throughout the document.
•<H1> This is a test </H1>
•A slash (/) indicates an ending tag
Major Features of the Internet HTTP and URLs
•
The transfer of Web pages is based on Hypertext
transfer protocol (HTTP).
•
Every Web page has an address, a Uniform Resource
Locator (URL).
•type://address/path/
•http://www.ncue.edu.tw/cc2002
•ftp://sunsite.unc.edu/pub/micro/pc-stuff
This address is for an
Internet server that uses
The hypertext transfer protocol.
This site is on the part
of the Internet known
as the World Wide Web.
This site belongs to a
company named Glencoe.
To find the specific Web pages
that accompany this book, your
browser follows the URL’s path
to a folder named “norton,” then
to a subfolder named “online.”
每一個網頁有它自己的唯一URL，它會指引您的瀏
覽器到文件的所在位置。
Major Features of the Internet Helper Applications and Search Engine
•
Helper application (or plug-in applications)
•Streaming audio and streaming video
•Use buffer-and-play technique to play a large file
without waiting for the entire file to download
•Virtual Reality Modeling Language (VRML)
•
Search Engine
•Use powerful data-searching techniques to discover
the type of content available on the Web.
Major Features of the Internet - E-Mail
•
Electronic mail (e-mail) is the most popular reason
people use the Internet.
•
To create, send, and receive e-mail messages, you need
an e-mail program and an account on an Internet mail
server with a domain name.
•
To use e-mail, a user must have an e-mail address,
which you create by adding your user name to the
e-mail server's domain name, as in [email protected].
Major Features of the Internet - News
•
One Internet-based service, called news, includes
tens of thousands of newsgroups.
•
Each newsgroup hosts discussions on a specific topic.
A newsgroup's name indicates its users' special topic
of interest, such as alt.food.cake.
•
To participate in a newsgroup, you need a
newsreader program that lets you read articles that
have been posted on a news server. You can post
articles for others to read and respond to.
•
Thread of articles: a list of related articles
Major Features of the Internet - Telnet
•
Telnet is a specialized service that lets you use one
computer to access the contents of another computer –
a Telnet host.
•
A Telnet program creates a "window" into the host so
you can access files, issue commands, and exchange
data.
Major Features of the Internet File Transfer Protocol (FTP)
•
File transfer protocol (FTP) is the Internet tool used to
copy files from one computer to another.
•
Using a special FTP program or a Web browser, you
can log into an FTP host computer over the Internet
and copy files onto your computer.
•
FTP is handy for finding and copying software files,
articles, and other types of data. Universities and
software companies use FTP servers to provide visitors
with access to data.
•
Archie: the searchable index of FTP files
Major Features of the Internet –
Internet Relay Chat (IRC)
•
Internet Relay Chat (IRC) is a service that allows
users to communicate in real time by typing text in a
special window.
•
Like news, there are hundreds of IRC "channels,"
each devoted to a subject or user group.
•
You can use a special IRC program to participate in
chatroom discussions, but many chatrooms are set up
in Web sites, enabling visitors to chat directly in their
browser window.
Major Features of the Internet –
Internet Relay Chat (IRC)
•
Another twist on chat is instant messenger software
•MSN Messenger Serivce, ICQ
•http://www.geocities.com/Tokyo/4097/icq/
•http://messenger.msn.com.hk/Default.asp?MSID=27
17b66146274db48de0f0d27d5b7a13
Services Related to the Internet
• Online Services.
• Peer-to-Peer Services
Online Services
• An online service is a company that provides access to
e-mail, discussion groups, databases on various
subjects, and the Internet.
• America Online, CompuServe, and Prodigy are
examples of popular online services.
Peer-to-Peer Services
• Peer-to-Peer (P2P) services are distributed networks
that do not require a central server to manage the files.
•Allow an individual’s computer to communicate
directly with another individual’s computer and even
access files on that computer.
立即傳訊軟體讓使用者在網際網路上以點對點(peer-to-peer)
的連接方式進行聊天
Internet-Related Features in Application
Programs
•
Popular application programs, such as word processors
and spreadsheets, feature Internet-related capabilities.
•
Using these special features, you may be able to create
content for publication on the Internet or view content
directly from the Internet.
Internet-Related Features in Application
Programs
•
Retrieving Content:
•
Creating Content: three methods exist
•Save as HTML Command: e.g. Save As HTML in Word
•Web Templates: predesigned web page
•Wizards: A wizard appears as a series of dialog boxes
that ask questions and prompt you to make choices.
Sectiion 8a review
•
Name the two organizations that created the network
now called the Internet.
•
Explain the importance of TCP/IP to the Internet.
•
Describe the basic structure of the Internet.
•
List the major services the Internet provides to its users.
•
Identify two key Internet-related features found in
many software applications.