A tour of a few sites. The underlined portions below are the web addresses of the various sites. These are called URLs. Access to Internet services and resources is specified as a URL or Uniform Resource Locator. There are many examples of URLs throughout this guide. It's the "address" of an internet resource. The most general form of a URL is
service://doman-name-of-site-supplying-service/full-path-name-of-item
In addition to URLs that begin "http://," others begin with "gopher://," "telnet://," or "ftp://" to denote services other than hypertext documents. Some of these other services are described below Be careful that the URLs you type are correct in terms of upper or lower case of letters, spelling, and punctuation.
If you've clicked on a link within the document, you follow that link and the current document is replaced or another window pops up. The color of the link will be different when if you return to your original documant, helping you to keep track of where you've been.
Clicking on text or icons in the border of the window pops up a menu bar and you choose an action from it.
Clicking on an icon or a button in the border, in some cases, causes an action without your having to choose from a menu bar or dialog box.
How the WWW Works
The WWW project was started to give a single means of access to the services and resources on the Internet.
You access the WWW by using a program called a web browser.
You use a broswer to contact or access a site on the WWW. The item you retrieve is called a Web page. The starting point for a particular site or person is called a home page.
Some common Web browsers are
LYNX: Lynx is a text-only browser. No graphic images are displayed and the text display is very plain. Because no time is taken to download graphic images, Lynx may work faster than graphical browsers. You can access Lynx from your CWU VAX account by just typing LYNX at the $ prompt. If you don't have a VAX account, you can access Lynx by logging in as "LIBRARY," which does not require a password. Follow the library links to the University of Washington UWIN system and go to Internet Services.
You can get help running Lynx by typing ? or H after you've started
Lynx running. You can view and print Lynx documents by pointing your browser
to
http://www.cc.ukans.edu/lynx_help/Lynx_users_guide.html
(Note: In the URL above, spaces that appear to be blank are actually
occupied by an underscore
( _ ) character.)
NETSCAPE: Start Netscape now by clicking on the Netscape Icon on
your screen.
You should see the CWU home page screen. Go to the URL for this introductory
guide by entering the following in the "Location" window near the top of
the screen. http://www.cwu.edu/~warren/wwwintro.html
The browsers are fundamentally the same. They give hypertext access to the services and resources on the Internet so that you only need to select a title, phrase, word, or icon. The links to other resources don't have to reside on one computer or network
Then: The program searches a database of resources on the WWW (or other portions of the Internet)
Finally: The results are presented as a list of hyperlinks, ranked in order of relevance.
Three popular sites for searching are
We can apply these same methods of interaction, distributing information and communication to any activity: training, learning, recreation, or business.
The World Wide Web (WWW) is a part of the Internet, but it's not a collection of networks. Rather, it is information that's connected or linked together, like a web. You access services and resources, basically, through one interface or tool called a Web browser.
There are over 30 million users of the WWW and more than half the information that's transferred across the Internet is accessed through the WWW. Through a computer to terminal connected to a network which itself is connected to the Internet, and through the use of a program to browse and retrieve information that's part of the World Wide Web, users have access to a wide variety of services, tools, information, and opportunities.
All this activity is possible because tens of thousands of networks are connected to the Internet and exchange information in the same basic ways.
A Little More About Internet Technology
The Internet is a network of tens of thousands computer networks. These computers and networks communicate with each other by exchanging data according to the same rules or protocols, even though the networks and computer systems individually use different technologies.
How It Works
The Internet is a network connecting thousands of computer networks.
Each network on the Internet has a unique address, and the computer systems making up a network have an address based on the network's address. At a basic level the addresses are numeric, a sequence of four numbers separated by periods. An example is 198.104.67.106. You don't need to memorize numeric addresses, they can also be specified as names such as www.cwu.edu.
The Internet is a packet-switched network. Networks on the Internet agree to communicate by the Internet protocol (IP).
The networks on the Internet use hardware or a device called a router to communicate with other networks.
Information is broken into packets and each packet contains the address of the destination and the address of the sender. The packets are passed from one network to another until they all arrive and are reassembled into a message. As a packet is passed form one network to another network, a device called a router decides whether to accept packet or pass it on to another. Once it's accepted within a networks, it's the network's job to get it to a specific computer system.
Note that a packet is examined by several routers before it gets to its destination. This is a potential security problem. Also, packets can be forged, another problem.
The Internet is designed so the computer systems within one network can exchange information with computers on other networks. The rules that govern this form of communication are called protocols. Using the same protocols allows different types of networks and computer systems to communicate with each other.
This means a computer system or network has to be able to transform information from its own form into the form(s) designated by the protocols, transform information from the protocol's form to its own form, and it has to be able to send and receive information in that form. Two protocols used are Internet Protocol (IP) and Transmission Control Protocol (TCP). You'll often see these mentioned together as TCP/IP when dealing with the software needed to make an Internet connection.
As an example suppose we want to transfer a file or e-mail message from your home site to a computer in Hong Kong. The software at your site takes the file and puts in into packets with the address of the destination as part of the packet. Each packet is transmitted from your network on to another, and that network may pass it on to another, and so on until a packet reaches the destination network. The router at that network accepts the packet and delivers it to the final destination. Not all packets need take the same route and they may not arrive in order. It's up to the Internet software at the destination to make sure all the packets have arrived and to put them in order. The Internet protocol (IP) specifies the rules for moving packets form one site to another and another protocol, Transmission Control Protocol or TCP makes sure the packets have arrived and the message is complete.
Each computer system with a direct connection to the Internet has to have the hardware and/or software to allow it to work with packets. This usually means either a network card with TCP/IP software is in the computer you use or get a direct connection by using PPP (Point to Point Protocol) or SLIP (Serial Line Internet Protocol) software and a modem. If you're using a modem, but not using PPP or SLIP then you probably don't have a direct connection to the Internet, but you're contacting one which does.) It's up to the individual computer systems to take care of sending and receiving packets.
Domain Names and Addresses
Each node on the Internet has a numeric address called its IP address. Additionally most sites also have a name called the fully qualified domain name. These names are usually 3 or 4 strings separated by dots (periods). The names are associated with numerical IP (Internet Protocol) addresses
Domain Name IP Address www.cwu.edu 198.104.67.106 www.cdc.gov 158.111.4.16 www.bigbook.com 204.17.233.3 www.historychannel.com 206.128.187.102 www.loc.gov 140.147.248.7Try pointing your web browser to these sites by using their IP addresses instead of their URL name.
These domain names are part of an e-mail address and also used to access Internet services and resources.
To send electronic mail to someone you need to know their Internet address. For nodes that are directly connected to the Internet this address is usually
login-name@domain-name
To access an Internet service or resource you usually start a program, for example, a Web browser such as Netscape Navigator, and give the address of a remote site or service that will interact with the program you start.
Access to Internet services and resources is specified as a URL or Uniform Resource Locator. There are many examples of URLs throughout this guide. It's the "address" of an internet resource. The most general form of a URL is
service://doman-name-of-site-supplying-service/full-path-name-of-item
In addition to URLs that begin "http://," others begin with "gopher://," "telnet://," or "ftp://" to denote services other than hypertext documents. Some of these other services are described below Be careful that the URLs you type are correct in terms of upper or lower case of letters, spelling, and punctuation.
Client-Server
Many of the services and resources available on the Internet operate according to a client-server model. You run a program on your computer to access information on a remote system. The program on your computer, such as a Web browser acts as a client, accepting your input and then passing it on to the other system which is running a program that acts as a server. That is, it accepts requests form clients, acts on the request, and then send a response. The response then goes to the client which processes the response and presents it to the user.
When you start a Web browser the browser often presents information in a window. That information may be on your computer or may come from a remote site. The information comes to it in a specific format and the client displays it. You select an item or type in a URL and your program then uses the information in the URL to contact the appropriate server. The server receives the request and passes some information back to he client which then displays it for you in its window. For Web browsers this is done through one of several protocols, the most common one being HyperText Transfer Protocol or HTTP.
HTTP is what's used to allow access to the World Wide Web (WWW). You have a hypertext, hypermedia interface to all the services and resources on the Internet. This is done through a graphical interface where you select items with a mouse, click the mouse button, and access the resource.
Other client-server applications or protocols you're likely to see are
FTP
File Transfer Protocol, allows for transfer of file form one site to another, regardless of the format of the file. A vast number of software programs and documents are available via ftp.
Telnet
A remote login facility. The Telnet protocol allows a user at one computer
to login to another on the Internet, and use resources on the remote system
as if he were hard-wired or directly connected to that system. But, it's
not a direct connection; a virtual terminal session is created.
Remember, everything is passed as packets. You can run a session on the
CWU VAX by pointing your browser to
telnet://cluster.cwu.edu
This means that you can access your VAX account from any computer in
the world that has a world-wide web browser on it.
Gopher
A menu based document delivery system. Users can access various types of information such as files, documents, address books, and images. Also allows access to FTP, Telnet, and searchable data bases.
WAIS
Wide area Information System. A user from one location can search databases dispersed on the Internet.
Several client programs may exist and be used on a one computer and each can contact and interact with server programs throughout the Internet.
Getting Connected
In order to access the Internet you need hardware and software to become connected to a network as an Internet site. This is called an IP connection.
You need the software/hardware to be able to exchange packets with the systems on the Internet. This gives you a connection that allows you to work with the Internet in both a text and graphical mode. This is done in essentially two ways: a direct connection to a network from your computer which has a device installed called a network card with TCP/IP software, or a dial-up connection where your computer has a modem and software for SLIP or PPP. With either of these you've got access to all the services and resources on the Internet.
There are lots of folks who make their presence known, tell something about themselves by creating personal Web pages. These are documents that can be displayed on the world wide web and tell about the individual. Some examples may be viewed by going to the CWU home page and following links to the directory of faculty and student web pages, or by entering an individual's name in the search field of an internet search engine, such as Alta Vista.
Discussion Groups
With so many people having access to e-mail it's reasonable that groups are formed to discuss certain topics. There are over 6,000 such groups on all sorts of topics. Individuals exchange information with a group through electronic mail. To find interest groups take a look at
Usenet stands for "User's Network". This was started independent of the Internet. The information is called news, a collection of "articles" arranged into newsgroups. Information is exchanged between computer systems, with individuals selecting the newsgroups and articles to read or post. Very little control on topics or content. Individuals use software called a news reader to read and contribute to the information available through Usenet. TO take advantage of these you need access to a server called a news server. To see the variety of newsgroups available use the URL