Internet –Terminology and Summary Miss O’Grady YR 10 IST

What is the Internet? An interconnected network of thousands of networks Links academic, research, government, and commercial institutions Connects computers to about every country in the world. Growing too fast to measure its growth Too decentralized to quantify A network with no hard boundaries

WWW Chat Email File Sharing Games Music Downloading Files E- Commerce News Groups Research

ARPANET Pioneers Build an Unreliable Network ... on Purpose The Advanced Research Projects Agency NETwork (ARPANET) is the predecessor to the Internet: Developed at the request of the Department of Defence by a team of visionary computer scientists Launched in 1969 Its peer-to-peer networking philosophy and protocols were copied in other networks in the 1980s Disbanded in 1990, having fulfilled its research mission, but its technology spawned the Internet

Intranets and Extranets Intranets: A private network or group of networks that are permanently connected and use the protocols of the internet and WWW. Extranets: Private TCP/IP networks designed for outside use by customers, clients, and business partners of the organization which owns the extranet. ( An intranet that is accessible from locations outside of the physical intranet)

Internet Protocols Protocols are agreed sets of rules that enable and control transfer between computers. TCP/IP-Transmission Control Protocol/Internet Protocol- allows cross-network communication FTP- File Transfer Protocol -allows users to transfer files SMTP – Simple Mail Transfer Protocol HHTP – Hypertext Transfer Protocol POP – Post Office Protocol

Packet Switching A message is divided into separate packets to send over the internet, and is rejoined at the receiving end. Router- A device that connects two or more networks together. It looks data packets coming in, and determines which network to send them out to.

Packet Switching

TCP breaks messages into packets Each packet has all the information needed to travel from network to network Host systems called routers determine how to route transmissions IP is the address for the packets Each Internet host computer has a unique IP address Each address is comprised of four sets of numbers separated by periods, such as 123.23.168.22

Internet Access Options Dialup Connection Limited connection using a modem Full access dialup uses SLIP or PPP via modem Direct (Dedicated) Connection Computer has its own IP address and is attached to a LAN No need to dial up Broadband Connections DSL Service Newer, faster, and cheaper than ISDN Can share phone line with voice traffic Cable Modem Connection Allows Internet connections using shared TV cables Can exceed DSL speeds Carries increased privacy and security risks

Internet Access Options Satellite Connection Provides connection using DirecTV satellite dishes Wireless Broadband Connection Allows multiple computers to connect to a base station using short-range radio waves. Internet Service Providers (ISPs) Local ISPs provide connections through local telephone lines National ISPs offer connections on a nationwide scale We recommend viewing “Internet Service Providers (ISPs)" (PH_04_23.swf) here. You can find this media asset on the Instructor Resource Center CD-ROM or online at www.computerconfluence.com.

Internet Servers E-mail server acts like a local post office for a particular Internet host—a business, an organization, or an ISP File servers are common within LANs Also used to share programs, media files, and other data across the Internet Application server stores applications—PC office applications, databases, or other applications Makes them available to client programs that request them Might be housed at an application service provider (ASP), a company that manages and delivers application services on a contract basis Web server stores Web pages and sends pages to client Web browsers

Controlling Access to information on the Web Firewall -something that monitors all data communications and filters any data that it determines dangerous. Firewalls can be physical devices that are typically located between a router and a network switch (e.g.. corporate networks), or they can be software that runs on a computer (e.g.. home users). Cookie – small pieces of code that allow web authors to interrogate an end user’s computer (e.g. a cookie may keep track of how often a user visits a website. It allows personalized content to be sent to the end user. Proxy Server – can serve many purposes Act as an intermediary between a company’s network and the Internet (hides true address of workstations within company) Cache frequently visited web pages locally. This works well with static pages, but not dynamic pages like search engines

Internet Security Internet Threats Virus a small program created to cause problems on network or PC Hackers – people who try to hack into other’s computers Viruses, Worms and Trojan Horses Spy ware software gathers information about you and your family from your computer habits, and allows spamming companies to target emails and adware to you that better suit your shopping needs. Adware Illegal or Inappropriate content Delivery Suggestions: Student Handout: InternetSecurity_001.pdf; InternetSecurity_002.pdf The internet is open, accessible and everywhere. At the same time, there are no governing standards or entities to control content or security on the internet. This has resulted in poor security and many thousands of viruses proliferating the world wide web (some estimates indicate over 60,000 viruses are active on the web). For users to safely navigate the web without their computer becoming infected anti-viruses software is mandatory, and firewalls are strongly recommended. Follow the instructions under the Internet Security: Information Protection and Virus Protection topics in the Teacher’s Resource Guide. Have the students brainstorm the types of information that needs to be protected from hackers. The following points provide some guidelines: Home Users Bank account details Credit card details (especially in relation to online purchases) Online banking passwords Telephone and address (to protect against stalkers) Calendar with holidays scheduled in (vacant house for burglars) Car registration and vehicle identification (for false sale purposes) Birthdays and nicknames (to guess passwords) Email account (to prevent targeting by spam and adware) Businesses Bank account details, etc. Intellectual property such as patents (especially those that have not yet been filed) Copyright protected property Customer databases (to prevent competitors targeting them) Cost information Financial status (related to disclosure laws for publicly traded companies) Software controls for equipment (see NASA case study)

Internet Software Browser Software- web browsers provide a graphical user interface to the resources available on the Internet. Authoring Software Simple – plain text editor using HTML ( need knowledge of HTML) WYSIWYG – e.g. Macromedia Front page or Dreamweaver HTML – Hypertext Markup Language

Internet2 and the Next Generation Internet The Evolving Internet Internet2 and the Next Generation Internet Internet2 was launched by the government and various corporations in 1998 to provide faster network communications for universities and research institutions. Next Generation Internet (NGI) will consist of a nationwide web of optical fiber integrated with intelligent management software to maintain high-speed connections.

Internet Issues: Ethical and Political Dilemmas Filtering software to combat inappropriate content Digital cash to make online transactions easier and safer Encryption software to prevent credit card theft Digital signatures to prevent e-mail forgery Access and Censorship The Digital Divide

Lesson Summary The Internet is a network of networks that connects all kinds of computers around the globe and uses standard protocols to allow Internet communication to occur No single organization owns or controls the Internet You can connect to the Internet in several ways that provide different degrees of access to Internet services The Web uses a set of protocols to make a variety of Internet services and multimedia documents available to users through a simple point-and-click interface