© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Computer Literacy for IC 3 Unit 3: Living Online Chapter 1: Understanding the Internet

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Learning Targets 96.I can describe how to create faster, more reliable communications 97.I can describe networks of computers 98.I can describe the birth of the World Wide Web 99.I can describe how to connect to the Internet 100.I can discuss financing and controlling the Internet 101.I can describe security, privacy and ethics in regard to the Internet

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Traditional Phone Systems Circuit Switching wires leading back to a central office Star Configuration Switchboard Operator

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. System to Survive Major Losses Advanced Research Projects Agency (ARPA) Created by J.C.R. Licklider in 1962 Concept of a “Galactic Network” Advanced Research Projects Agency Network (ARPANET) Network of Networks Keep one path alive Computer provided millions of instructions per second

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. TCP/IP – Transmission Control Protocol/Internet Protocol Data divided into small packets Consisting of bits (b) and bytes (B) Checksum – sum of numbers in packet

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Data Travels – Increased Survival

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. TCP/IP Protocol Groups of rules used to manage data exchange File Transfer Protocol (FTP) Enables users to transfer files between computers Telnet Enables users to logon to remote computer (1972)

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Networks of Computers Local Area Network (LAN) Small geographical connection of PCs to share files and resources (printers, scanners, etc). Each element is a node Connected to a network server Peer-to-Peer network Computers are connected directly to each other without a server

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Servers on a Network File server – storing and retrieving files Print server – coordinating use of a shared printer Web server – storing and providing Web pages Database server – interpreting requests and retrieving data from a database Mail server – managing electronic mail

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Client – Server Relationship Client A computer connected to a server in a client/server network Server A computer that manages a network and all its devices

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Methods of Connections Infrared (IR) Twisted pair Coaxial cable Wireless Fiber optic cable

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Type Cost Distance Security Speed Twisted Pair Lowest<100 meters Good CoaxMedium meters Good Radio (wireless) LowUp to miles PoorFair InfraredLowShort and line of sight Excellent Fiber optic HighMany miles Excellent

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Network Wire Codes 10 BASE- T 10 – indicates speed = 10 MBPS T – indicates twisted pair 10BASE-T 4 4 – indicates 4 twisted pairs 1000 BASE-T 1000 MBPS 10Base-2 (Thin Coax) 10Base-5 (Thickwire Coax) 10Base- F (Fiber)

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Wide Area Networks (WAN) Further apart than a hundred meters Connections Twisted pair for short distances (inside buildings or small offices) Broadband coax, fiber optic, or radio for intermediate distances

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Connections Between Networks Bridge Used to send and receive data when networks are connected and use the same protocols Gateway Used to send and receive data when networks are connected and use different protocols

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Addresses on the Internet http Protocol gov g (TLD) Generic Top Level Domain au cc (TLD) Country Code Top Level Domain australia Domain name World Wide Web

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Role of Domain Name System Host Internet Protocol (IP) address Domain Name System (DNS) Domain Name Server Internet Corporation for Assigned Names and Numbers (ICANN) Registry Internet Service Provider (ISP)

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Internet Backbone

© 2010 Pearson Education, Inc. | Publishing as Prentice Hall. Birth of World Wide Web Browser Mosaic Netscape Microsoft Internet Explorer Mozilla Firefox Apple’s Safari Hypertext Markup Language (HTML) hello - the word hello bolded Hyperlinks –