INTERNET COMMUNICATION
Concept and terminology
Terms
Internet
Description
The internet is a collection of thousands of individual networks and
organizations, each of which is run and paid for on its own. Each
network cooperates with other networks to direct Internet traffic so that
information can pass among them.
Internet procedures and standards for protocols are laid out in RFCs
(Request for Comments) agreed upon by Internet users and
organizations.
Internet Societies (e.g. World Wide Web Consortium) makes
technological and architectural reommendations that pertain tol the
Internet. ISPs sells people monthly connection to the internet. Internet
Registrars are responsible for registering internet domains.
Internet Resources
World wide web, gopher, email, telnet, usenet newsgroups, bulletin
board, internet chats, video conference, FTP (file transfer protocol)
Clients and Servers
The Internet works on the client/server model of information delivery.
In this model, a client computer connects to a server computer on which
information resides; the client depends on the server to deliver
information and service.
Typically, the client is a software housed in a local personal computer
and the server is another software which houses in a usually more
powerful computer. The connection between the client and server is
maintained only during the actual exchange of information.
WWW萬維網萬維
網
(World Wide Web,WWW/3W) is a large system with a great number of
web servers scattered all around the Internet. These web servers can
respond to requests for information.
FTP檔案傳送
File Transfer Protocal, it is a protocal for downloading and uploading
files, software, games,...
Browser瀏覽器
Browser is a client program for viewing web pages. Examples: Mosaic ,
MicroSoft's Internet Explorer and NetScape's Netscape Communicator
HomePage首頁
The first web page of a web site.
WebPage 網頁
Every page in the web site.
Internet Address of
an email
The Internet Address of an email is made up of two major parts
separated by an @ sign. To the left of @ refers to the person who holds
the internet account. To the right of @ refers to the host name and
domain name of the address.
cklau@jcctm.edu.hk
peter@biz.zd.com
Search Indexes and
Search Engines
They are solutions to search for information on the internet.
Indexes present a highly structured way to find information. They
enable people to browse through information by categories.
Search engines are essentially massive databases. They are composed
of three parts: a spider which crawls across the Internet to gather
information; a database which contains all the information the spiders
gather; a search tool which allows people to use and search through the
database
Web Uniform
Resource Locator
URL
A Web URL is made up of four parts:
http://www.jcctm.edu.hk/~cklau/index.htm
http://www.sample.com/sales/tools/electric/drills.htm
The first part indicates what type of transfer protocol will be used to
retrieve the specified document.
The second part is the specific host computer on which the document
resides. This part is also called the domain.
The third part is the directory on the host computer that contains a
specific web site.
The last part is the filename of the specific web page you are requesting
Domain Name
System DNS
The DNS translates the plain English address into numbers that Internet
computers can understand. Domains are organized in a hierarchical
manner, so that beneath major domains are many minor domains. (e.g.
jcctm.edu.hk) Computers called name servers are responsible for
keeping track of the domain names of computers.
HTML
HTML(Hypertext Markup Language) is a special kind of markup
language for creating hypertext documents. A hypertext document
enables you to format information in a friendly, interactive way.
Hyperlink超連結
The linking between web pages.
TCP/IP (Transmission Control Protocol /Internet Protocol) is a set of
rules governing how pieces of messages are transmitted in a packetswitch network especially the Internet.
TCP/IP 通訊協定
The transmission control protocol is responsible for breaking down
information into packets and recombining them on the computer that
receives them.
The internet protocol is responsible for routing the packets. Each
computer will be assigned an IP address when it connects to the
internet. IP is a 32 bits code, which represents the country/district and
other information.
e.g. hknet
Terms
202.67.240.2
hkcampus
Description
202.45.176.1
Since the IP address is quite difficult to remember, domain name
represented by text overcomes this problem. Some types of domain
name are shown below:
.com -- commercial ; .edu --- education ; .gov ---government ;
.hk --- Hong Kong ; .cn --- China ; .tw --- Taiwan
Domain name/DNS
e.g. www.pchome.com.hk --- The server serves WWW, the name of
the commercial company is pchome, which locates in Hong Kong.
Domain Name System -- It is a database system which stores the IP
addresses of Domain Name.
e.g. www.hku.hk
147.8.145.30 ;
www.polyu.edu.hk 158.132.18.1
http
(HyperText Transfer Protocol) is a protocol of WWW , WWW Server
responds to the WWW Client's requests. Then the browser displays the
effects of the information according to the rules.
Hubs, Bridges,
Gateways, Routers
Hubs link computers in a LAN. Bridges and gateways links LAN with
one another. Routers play a key role in the internet traffic.
Internet Service Provider which provide the Internet
services.Comparison table of different ISP:
ISP
http://www.glink.net.hk/~alexque./hkinternet.html
UNIX
It is a family of operating systems that are the most widely used in the
computer world. Since most of the computers in the Internet use UNIX.
many people consider the Internet and the UNIX not separable.
Especially in the uploading and downloading of web pages.
Some UNIX commands are shown as follow:
mkdir newdir -- make directory ; rmdir newdir --- remove directory
Some auxiliary programs to play a sound or animation.
Example : real-audio , real- player, Live 3D, Shockware, Cooltalk
plug-in
Download URL:
http://home.netscape.com/comprod/mirror/navcomponents_download.html
http://www.cuhk.edu.hk/cgi-custom/rthk/newsindex.pl