Definition of Internet

Internet

DEFINITION OF INTERNET

As ISOC (Internet Society) states:[1]

The Internet is a global network of networks enabling computers of all kinds to directly and transparently communicate and share services throughout much of the world. Because the Internet is an enormously valuable, enabling capability for so many people and organisations, it also constitutes a shared global resource of information, knowledge, and means of collaboration, and cooperation among countless diverse communities.

Also another definition from Berkeley is:[2]

The Internet is a network of networks, linking computers to computers sharing the TCP/IP protocol. Each runs software to provide or "serve" information and/or to access and view information. The Internet is the transport vehicle for the information stored in files or documents on another computer. It can be compared to an international communications utility servicing computers. It is sometimes compared to a giant international plumbing system. The Internet itself does not contain information. It is a slight misstatement to say a "document was found on the Internet." It would be more correct to say it was found through or using the Internet. What it was found on is one of the computers linked to the Internet.

In addition, this definition extends with the available Internet services:

Electronic mail (e-mail): Permits you to send and receive mail. Provides access to discussion groups often called Listservs® after the software they operate under.

Telnet or remote login: Permits your computer to log onto another computer and use it as if you were there.

FTP or File Transfer Protocol: Allows your computer to rapidly retrieve complex files intact from a remote computer and view or save them on your computer.

Gopher: An early, text-only method for accessing Internet documents. Gopher has been almost entirely subsumed in the World Wide Web, but you may still find gopher documents linked to in Web pages.

The World Wide Web (WWW or "the Web"): The largest, fastest growing activity on the Internet.

HISTORY OF INTERNET

As Internet Society states first social aspects of Internet has been mentioned by J.C.R. Licklider of MIT in 1962 as a series of memos. This idea of “Galactic Network”, imagined as every computer connected each other and make available to reach and share data, applications and so on. This “Galactic Network” likes today’s Internet. Licklider was also the first head of the computer research program at DARPA (Defense Advance Research Projects Agency)[3]. Then in 1965 two computers, one from Massachusetts other from California connected with low speed dialup connection. After this achievement DARPA developed concept of Network and developed a plan called “ARPANET”, in late 1966. First ARPANET node was established UCLA campus and then wide spread of ARPANET was began, first used network protocol was Network Control Protocol which is completely absolute today. Then DARPA researchers implement first e-mail program for overcoming coordination problems and this tool become very popular since then.

In 1972, ARPANET advanced with the packet radio program that allows send and receive data with radio waves and this made ARPANET more rapidly and cheaply spread. However, this advancement lead some problems. NCP protocol was not support machine addressing and was not allowing data loss, if this is the case machine that runs remote program halts and communication was lost. To overcome this problem, R. E. Kahn developed a new protocol that allows lossy communication that called TCP/IP, and this become the communications protocol and NCP became as device driver that TCP/IP used over.

After 1973, International Networking Working Group established for detailed work on TCP/IP protocol to enhance. These efforts resulted in global machine addressing and more reliable data transfer. Also an alternative protocol of TCP, namely UDP was developed. These two protocols handle data recovery and run of services. During these years, FTP, Telnet, worms (namely viruses) was also introduced to the life of ARPANET and network and data security introduced.

With the wide spread of Personal Computers (PCs), ARPANET grew very rapidly and network class concept have been introduced. A class of networks is assigned to Nations, B class for regions and C class for local area networks. Also due to the increase of network nodes, it became nearly impossible to remember all hosts’ addresses, and Paul Mockapetris of USC/ISI invented Domain Name System (DNS). This enabled hierarchical resolution of host addresses. Furthermore, this increase challenged the structure of routers and gateways and pushed them to make advancement both in working algorithms and structures.

After completely giving up use of NCP protocol and started to use TCP/IP as the unique protocol of ARPANET, military network was pushed to disintegrate from ARPANET because TCP/IP enabled a network to be separated from one another, in 1983 MILNET established.

In 80’s there were many networks like Department of Energy’s MFENet for working on magnetic fusion energy, HEPNet for high-energy physicists. Moreover, NASA space physicists’ SPAN, and Computer Science Community’s CSNET, National Science Foundation’s NSFNet was already operating. In addition, USENET, and BITNET networks was also used. All of these networks became a part of Internet and they started to use TCP/IP as a main protocol. One of the first, NSF, accepted current Internet organization infrastructure and after that this structure named as Internet Activities Board (IAB).

In 1992, IAB re-organized and changed name in to Internet Architecture Board. Then IAB started work under Internet Society.

In 1987 there became visible another problem that, TCP/IP protocol was not enough for operation of routers, because of the huge amount of computers connected to Internet. Many protocols had been introduced but SNMP (Simple Network Management Protocol) was chose and widely spread between routers.

In recent years World Wide Web gained commercial and public interest and grew rapidly. In order to ensure the standard that used on WWW, W3 consortium have been established and have been developing WWW standards such as HTML, DOM, DHTML, CSS, XML, XSL…

Currently Internet architecture maintained by IAB, naming and IP assignments are held by InterNIC.

INTERNET SERVICES

File Transfer Protocol

Handles Data transfer among computer that connected to Internet.

Telnet

This protocol (application that uses this protocol also named as Telnet) deals with remote access to servers and use of those servers’ resources

SMTP

This protocol handles to send e-mails.

POP3 and IMAP

These protocols are used for both sending and receiving mails.

WWW

This service uses HTTP protocol for sharing multimedia resources over computers.

HOW INTERNET WORKS

Internet, being a network of networks, runs with computer protocols plus necessary hardware. The protocols look like a language that people speak with each other. In this manner, protocols enable two or more computer to communicate each other. In order to ensure communication, these protocols have strong definitions, like a language have. If this is not the case, like accents in languages, it became very hard to communicate with one difference, human can understand variations of a language but computers cannot.

Imagine that, you are in crowded room and every one wants to speak with each other, than think about it, you have two ears and one mouth, in one moment you cannot speak with others so you must find a way that connects you to everyone in that room. If this is the case, easiest way to speak with one another in the other corner of the room, to whisper someone nearest to you and say her/him to destination and wait for the response. In network environment, this is not too much different, since connecting each computer with others is expensive and nearly impossible, computers with one networking device must send and receive data to/from one computer at a moment. Also they use whisper method and they use protocols that enables them to show destination and source (who send data) addresses.

In Internet environment, there is one main and only protocol used while communicating is TCP/IP. This protocol includes sender address and receiver address, so that it is possible to reach every part computer connected to Internet. However, imagine that you are speaking with your friends and in that room there are Germans, how will you understand with each other if no one in the group do not know Deutsche. Then you need a bridge between you and others speak in Deutsche. Well you find a translator but this translator cannot send your message to Germans, since the speaking language of that room is English. In this case you need a Turkish to English translator that bridges your message to whom that routes with in the other people to your destination and another bridge that translates your message to Deutsche.

In computer networks, this not too much different, if you want to send a message to remote computer from your LAN connection then you must have a translator, thus bridge and the routers that direct your message to destination address and if there is another LAN such as Apple computer networks than another bridge that translates your message to Apple Talk. If the correspondent computer is connected to Internet there is no chance to occur other possibilities.

Intranet

Intranet is the corporation/organization’s own network. For example METU Intranet means, METU’s departmental computer labs, administrative and academic units’ computers, computer center’s computers (including CC dormitory labs).

Extranet

Extranet is used for the corporation/organization’s link with suppliers/vendors/partners/customers etc. Extranet’s use TCP/IP and Internet providing link with those. If we think about METU, then METU’s extranet may include some other universities that work on same projects, some hardware/software suppliers, some banks etc.

Server

This type of computers is generally a powerful computer with more powerful processor, RAM, hard disk etc. It stores data of users and have the ability to share data/resources among users. Such as orca, almost every day we connect that computer with telnet and check mails.

Client

Client is the computer that connects to server to use server’s resources and/or sharing data. If we think about our computer labs than there is a computer called EFNT2 named as CEIT domain, every user data (including user names and passwords) stored on a server and when user opens a computer from the lab, this computer (client) connects to server and receives data.

Dummy Clients

This type of clients does not have a processor and memory. They are always connected to server with special cables directly connected to server. Dummy clients may be imagined as a computer with many keyboards and monitors that are connected to a computer, doing different tasks

Intelligent Clients

This type of clients has processor and memory and can perform almost operations without a server except server’s resources such as server’s disk space (H drives of our labs) or printer.

DNS

DNS (Domain Name System) allows the use of logical phrases instead of computer number. They are easy to remember.

URL

URL (Uniform Resource Locator) has three parts:

/ / /index.html
Protocol name / DNS address of server / Path and name of the desired document

This representation of files over Internet makes easy to reach and use resources

URI

URI (Uniform Resource Identifier) is the generic set of all names/addresses that are short strings that refer to resources.

URN

URN (Uniform Resource Name):

1. An URI that has an institutional commitment to persistence, availability, etc. Note that this sort of URI may also be a URL.
2. A particular scheme, which is currently (1991,2,3,4,5,6,7) under development in the IETF, which should provide for the resolution using Internet protocols of names, which have a greater persistence than that currently, associated with Internet host names or organizations. When defined, a URN (2) will be an example of a URI.

URC

Uniform Resource Citation, or Uniform Resource Characteristics. A set of attribute/value pairs describing a resource. Some of the values may be URIs of various kinds. Others may include, for example, authorship, publisher, data type, date, and copyright status and shoe size. Not normally discussed as a short string, but a set of fields and values with some defined free formatting.

WWW TECHNOLOGIES

HTML

HTML (Hyper Text Markup Language) is the standard for building web pages, its development by WWW consortium have been stopped due to its limitations. However it is very easy to implement and can be written with a text editor. This technology allows you to put multimedia components together in a page, for example text, sound, images, and movie. This technology does not allow full user interaction and any dynamic content.

If you want to begin with HTML then it’s nice to start with W3C’s tutorial on wish you luck.

Latest HTML version XHTML 1.0 which is based on HTML 4.01 with XML features, which is also a stage between switching HTML technology to XML.

DHTML (Dynamic HTML)

In fact this is not a version of HTML provided by W3C consortium, but this is related with another event, Document Object Model (DOM). This uses bare HTML and allows giving a name to each HTML element (object) and change it’s contents. DHTML gives more interaction to users, thus more tasteful web surf. It’s a combination of JavaScript and HTML (after HTML v3.2 mostly in v4.xx).

CSS

Cascading Style Sheets gave control of defining each HTML elements outlook and this is vital for DHTML scripting.

XML

XML (eXtensible Markup Language) is a way of putting structured data in to a web page without focusing on whether what type of multimedia component. This newly developed technology will promise more things on WWW pages. This standard will avoid different outlook of same page in different platforms such as UNIX, Windows, Linux and even different programs, Netscape, Internet Explorer etc...

XSL

XML (eXtensible Stylesheet Language) have much advancement over CSS and allows scriptwriters to define even more style properties such as place on page, outlook of style (size, borders, background color), in different operating systems and/or different devices (pamphlets, catalogs, books, etc.).

SMIL

SMIL (Synchronized Multimedia Language) aims to schedule multimedia events via WWW. In order to achieve this goal, it has very structured, XML like language and, scriptwriters basically writes at what time a multimedia event occur. This will be very beneficial for WWW oriented courses that uses multimedia.

HOW TO FIND INFORMATION ON WWW

Think About Topic

This is the key for successful web search, if you do not know what you are searching for; even you search the topic for years you might not get the necessary information. Think about what you want to learn about your topic. Think about alternative keywords, synonyms or acronyms, whether suffixes are necessary or not.

Analyze the Topic

If you do not analyze the topic or you do not have enough information for the topic ask to some experts for general knowledge, then how much in depth information you need and what type of information you need.

Search the Topic

While you are searching look the information you gathered and reanalyze the topic and check whether you had necessary information or not. If you missed a point in previous analysis than include it but be careful, adding too much detail to a research will result in missing your starting point. Good Luck 

References:

Internet Society

Matthew Grey

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[1]

[2]

[3] The Advanced Research Projects Agency (ARPA) changed its name to Defense Advanced Research Projects Agency (DARPA) in 1971, then back to ARPA in 1993, and back to DARPA in 1996.