Lecture 10

The Internet

Internet and Society

• Medium making fundamental changes in the nature of communications, entertainment, and commerce– business communication between suppliers, co-

workers, and customers– email between friends and family– personal services: banking, shopping, travel

reservations, research

Network of Networks

• A connection of multiple networks

• Networks communication with each other over a suite of standardized protocols– TCP/IP sends data broken up into “envelopes”

or packets over the Internet

• Traffic sent in gigabit speeds over lines connected with routers and switches

Network of Networks

• High-speed lines are the backbone of the Internet

• WWW makes it possible to navigate from resource to resource on the Internet by clicking on highlighted text or graphics

• Multimedia, hypermedia way to view information

Connections to the Internet

• T-1

• T-3

• ISDN

• Cable TV facilities

• Internet Service Providers (ISPs)

• DSL

• Twisted pair

History Internet

• 1969: started by the Department of Defence– ARPANET– to enable scientists at Universities to share

research information from distant locations– originally designed to develop at network

secure enough to withstand a nuclear attack

First Use of Internet

• Based on packet switching

• Packet switching breaks up the data to be transferred so that multiple computers can share the same data line

• Separate data line not necessary for transmitting

• In case of attack, as one computer goes down another can be used

1984

• More sites added to the ARPANET, term Internet started to be used

• ARPANET shut down, Internet left intact

• 500 computers on the Internet– 1987: oversight of the Internet transferred from

the Department of Defense to the National Science Foundation

Expansion of Users

• Computer hobbyist groups rally around Internet– newsgroups formed around special interest

groups such as: cooking, technology and lifestyles

• sexually oriented groups

• religious groups

1990

• Until this time Internet completely text based

• No graphics, pictures, or colors

• All tasks done without point-and-click assistance of a browser, instead had to learn commands like– get mail– “j” for next message, etc.

WWW

• World Wide Web browser developed in 1989

• Is a graphics based vehicle to link users to source of information

• Users click on graphics or text to be transferred to another site

• 1993: Mosaic browser developed at U of Illinois

Bulletin Board Systems

• Used independently from the Internet• Allowed people with modems to read information

and post information on a PC– to post bugs in software

– downloading engineering designs

– information on specifications for requests for proposals

– to chat and exchange ideas on specific topics

– replaced by WWW

Who Runs the Internet?

• Internet Society• Internet Assigned Numbers Authority• Internet Corporation for Assigned Names and

Numbers• Internet Engineering Task Force• Network Solutions Inc.• IOPS.ORG• WWW consortium

Who Owns the Internet?

• No one organization owns the Internet

• World wide arrangement of interconnected networks

• Network service providers: ATT, Cable & Wireless, Sprint, UUNET, GTE, MCIWorldCom carry Internet traffic

Who Owns the Internet?

• Network providers own the high-speed lines

• Tier 1 providers own nationwide networks

• Tier 1 providers lease fiber lines from carriers such as ATT and connect their own switches and routers the leased lines

• transfer data between locations called “peering” sites

Peering

• A way to exchange data between networks

• Also called a network access point

• First funded by the NSF

• Now set up privately by: GTE Internetworking, MCI WorldCom, Sprint, etc

• “Meeting places” to exchange data

Internet Services

• FTP: file transfer protocol– to log onto a computer at another site to retrieve

copies of text files

• SMTP: simple mail transfer protocol

• Archie: developed to simplify FTP by enabling searches

• Gopher: precursor to web browsers, more menu driven than Archie

Telnet

• Service for creating an interactive session with a computer on a different network

• Lets users log onto another computer located on the Internet as if they are a local terminal

• Telnet pilot.msu.edu

Linking and Graphics

• Way to make using and navigating the Internet easier

• Not a separate part of the Internet• Graphical way to use the Internet• Provides links to information using text and

graphic images embedded in documents to move from one site to another

• Commands no longer necessary

WWW

• Created in 1989 by Tim Berners-Lee at CERN

• European Lab for Particle Physics

• Basic concepts:– any type of client should be able to find

information worldwide without needing to know a particular computer language using any type of terminal

HTML

• Hypertext markup language came out in 1991

• tool used to create Web documents

• authoring software that controls the look of a web page

• all commands start and end with <> signs

• now software available to do this for you

XML

• Extensible Markup Language

• Web language used to create standard “labels” or fields within Internet pages

• Allows for exchanges between different computer applications and organizations– search for “part #”, when data base stores it

under “part number”

VXML

• Voice Extensible Markup Language used for speed recognition

• Standard way to access the Web via voice commands

• ATT, Lucent and Motorola– goal to be able to hear for example traffic

updates or stock quotes by dialing up the Internet from a phone

Home Pages

• Default first page that users see when visiting a Web site

• Document created using HTML

• Web pages are connected with hypertext links, which are highlighted pieces of text that transfer surfers to another site or page

Hosting

• The computer or server at which documents or databases for Web pages are located– Corporations

– Internet Service Providers

– Hosting companies

– Universities

• Making documents available on Web is called “publishing” to the Web

Hosting

• Requires:– providing telephone connections to the Internet– security to keep hackers out

• CSP: commerce service provider

• ISP: internet service provider (AOL)– portal sites: Lycos, Yahoo also provide hosting

Browsers

• Graphical interface between users and Web• Provide the graphics capability associated

with the Web• Allows users to go directly to any home page

by typing in the address or bookmark– Mosaic first browser (U of I and CERN)– Netscape Navigator by Netscape– Internet Explorer by Microsoft

E-Mail

• Invented by Ray Tomlinson, engineer at BBN in Cambridge, Massachusetts, 1972

• Based on service that is part of the suite of protocols called TCP/IP– SMTP– specifies addressing conventions

• mail to multiple users, how to carbon copy

• user name and their computer (@)

E-mail

• First used within organizations within buildings

• Progressed to:– LANs– commercial electronic mail services offered

independent of Internet– now widely available from various sources

E-mail Attachments

• ASCII text exchange not sufficient, businesses needed to exchange:– spreadsheets– brochures– Powerpoint and Word documents

• MIME developed as standard for sending attachments

Internet2

• Introduced to develop new networking protocols and technologies

• Fiber optic network connecting 130 universities

• Based on high-speed IP protocols

• Future of it not yet clear, need of it not yet clear

Privacy on the Web

• Loss of privacy while on-line major concern of net users– tracking what sites you may have visited– personal information placed on the web– sites that collect email addresses without a

users knowledge, which are marketed later– email read by non-recipients

Cookies

• Originally designed to benefit users

• Online organizations which require user ID and passwords could store this information in the form of a cookie so that repeat visitors to a site could avoid having to fill out form information on each visit

• http://www.cookiecentral.com/ccstory/index.html

Cookies

• Now used by advertisers and marketing groups to track and target user habits on the web

• Cookies can be matched to the profile of a user's interests and browsing habits

• Also used to keep track of how many times a user has been shown a banner at any web site

Internet Addresses

• Availability is running out and disputes are arising concerning who has the power to give address out

• URL: uniform resource locator– based on TCP/IP protocols, IP address– bit or octets in address– left of @ user name to the right domain name– domain name = computer address

Internet Address

• To the right of the organizational name description of the type of organization using the address, this is a top level domain

• Countries outside US use geographical top-level domain nameS– Netherlands = NE– Belgium = BE– Bolivia = BO

Domain Names

• .com = commercial business

• .org = non-profit organizations

• .net = networks

• .edu = educational institutions

• .gov = governmental bodies

• .mil = the military