© 2007 The McGraw-Hill Companies, Inc. All rights reserved The Internet Chapter 22

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Overview In this chapter, you will learn to –Explain how the Internet works –Connect to the Internet –Use Internet software tools

© 2007 The McGraw-Hill Companies, Inc. All rights reserved How the Internet Works Historical/Conceptual Internet

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Internet Tiers Tier 1 (main tier) –Nine companies –Own long-distance, high-speed fiber optic networks called backbones –Interconnect at network access points (NAPs) in major cities

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Internet Tiers Tier 2 –Smaller regional networks –Larger ISPs that provide Internet access are often Tier 2 providers Tier 3 –Even more regional networks Built-in redundancy –Decentralized –Can easily adapt to failures on network

© 2007 The McGraw-Hill Companies, Inc. All rights reserved TCP/IP: Language of the Internet TCP/IP is the common language of the Internet –Suite of protocols Hypertext Transport Protocol (HTTP) –Most common protocol that provides structure for the World Wide Web An Internet browser uses HTTP –Internet Explorer –Mozilla Firefox

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Internet Service Providers Internet service providers (ISPs) gain access to Internet through backbone –Leased from Tier 1 and Tier2 providers Users gain access to the Internet thru ISPs

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Connecting to an ISP requires –Hardware for connectivity Modem and working phone line DSL or cable modem –Software (protocols) Governs the connection and data flow Connection Concepts

© 2007 The McGraw-Hill Companies, Inc. All rights reserved CompTIA A+ Essentials Essentials Getting the Right Sound Card Connecting to the Internet

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Ways of Connecting Dial-up –Analog –ISDN Dedicated –DSL –Cable –LAN Wireless Satellite

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Dial-up Requires a Modem The term modem is an abbreviation for modulator/demodulator –Enables computers to communicate with each other via standard telephone lines –Converts analog signals into digital signals –Converts digital signals into analog signals

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Modems A modem uses serial communication –Transmits data as a series of individual 1s and 0s Universal asynchronous receiver/transmitter (UART) –Converts serial into 8-bit parallel data

© 2007 The McGraw-Hill Companies, Inc. All rights reserved UARTS on Modems

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Baud rate is the basic cycle of time that a modem uses as its carrier frequency –Maximum baud rate of a phone line is 2400 baud The modem speed is measured in bits per second (bps) –Modems can pack multiple bits into a single baud –14 bits × 2400 baud = speed of 33.6 Kbps Baud Rate

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Modern modem standards are referred to as V standards –Set by the International Telecommunication Union—Telecommunications Standardization Sector (ITU-T) –Both standards offer download speeds of just under 56 Kbps V.90 upload speeds of up 33.6 Kbps V.92 upload speeds of up to 48 Kbps Rarely get throughput greater than 48 Kbps Communication Standards

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Flow Control (Handshaking) Hardware flow control uses extra wires called ready to send (RTS) and clear to send (CTS) –Called RTS/CTS –When in doubt, use hardware flow control PCs handle local flow control using hardware or software Software flow control uses special characters to signal the beginning and end of data transmission –Called XON/XOFF –Slower than hardware flow control and rarely used today

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Modem Connections Modems connect to the PC in one of two ways –Internal modems connect to a PCI or PCI Express expansion slot –External modems connect through a serial port or USB port

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Dial-up Networking Dial-up networking –Uses information from your ISP The dial-up phone number, username, password, and other special configuration parameters –Configured in Network and Internet Connections applet Select Set up or change your Internet connection and use the wizard

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Dial-up Networking Completing the setup of a dial-up Internet connection

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Dial-up Networking Uses PPP protocol –Point-to-Point protocol (PPP) –Streaming protocol developed especially for dial-up Internet access Most dial-up errors are user errors –Turn the volume up and verify the connection –Listen for a dial tone –Listen for “modem talk” instead of a person answering the phone

© 2007 The McGraw-Hill Companies, Inc. All rights reserved ISDN Integrated Services Digital Network (ISDN) –Phone companies have upgraded their network infrastructures to all digital lines (except for the line from your phone to the central office) –ISDN uses channels B (Bearer) used for data and voice at 64 Kbps D (Delta) used for setup and configuration information at 16 Kbps Basic Rate Interface (BRI) –Most common setup –Two B (total of 128 Kbps) and one D channel

© 2007 The McGraw-Hill Companies, Inc. All rights reserved DSL Digital subscriber line (DSL) –Uses a regular phone line but special equipment at both ends –Much faster than dial-up: Upload: 384 Kbps Download: 2 Mbps or greater –Installation requires a NIC and DSL receiver (often called a DSL modem) –Must be within 18,0000 feet from the closest main phone service switching center

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Cable –Uses cable TV connections Connect the RG-6 or RG-59 coaxial cable to a cable modem Connect modem to a NIC in the PC with UTP cable –Very fast speeds—as fast as DSL or faster –Bandwidth is shared with other users, which can affect performance

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Other Internet Connections LANs –Most companies connect their network to the Internet through an ISP –Users connect through the LAN Wireless –Wireless connections require access via wired network –If wired network has access, wireless devices can use this wired network via a WAP Satellite –Uploads previously done through modem –Initial connections still must be made through a modem

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Internet Connection Sharing Internet connection sharing (ICS) –Allows one computer to share single Internet connection with multiple devices –Available since Windows 98 SE –Requires a LAN between the devices first

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Windows XP Firewall Built into Windows XP –Originally named Internet Connection Firewall (ICF) –Changed to Windows Firewall in SP2

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Internet Software Tools

© 2007 The McGraw-Hill Companies, Inc. All rights reserved World Wide Web The World Wide Web (WWW) provides a graphical face for the Internet –Web servers house Web sites –Web browsers access the files on Web servers Web browsers are highly configurable –A proxy server enables multiple connections to the Internet to go through one protected PC Similar to ICS, but more sophisticated

© 2007 The McGraw-Hill Companies, Inc. All rights reserved World Wide Web Security and scripts –Active programs and scripts such as Java and Active Server Pages Can be useful and powerful Can be malicious –Internet Explorer has configurable options Tools | Internet Options | Security tab lets you set security levels

© 2007 The McGraw-Hill Companies, Inc. All rights reserved HTTP vs. HTTPS HTTP provides no encryption HTTP over Secure Sockets Layer (HTTPS) –Provides encryption –Use when submitting personal information such as credit card numbers, phone numbers, etc. –Verify HTTPS is being used two ways Lock icon HTTPS appears in address bar

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Two most popular programs –Microsoft Outlook Express –Mozilla Thunderbird protocols –Post Office Protocol version 3 (POP3) Used for receiving –Internet Message Access Protocol (IMAP) Used for receiving mail, but with more features than POP3 –Simple Mail Transfer Protocol (SMTP) Used for sending

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Configuring –Can use name or IP

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Newsgroups Use a newsreader program to access newsgroups –Outlook Express most common newsreader (free) –News servers run Network News Transfer Protocol (NNTP)

© 2007 The McGraw-Hill Companies, Inc. All rights reserved File Transfer Protocol File Transfer Protocol (FTP) –Used to share files –Requires an FTP server on one end and an FTP client on the other WS_FTP is a popular client Internet Explorer and other Web browsers also support FTP –Public FTP servers allow anonymous login User Name: Anonymous Password: address

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Voice over IP Voice over IP (VoIP) –Enables voice calls over the network –Works with any type of high-speed connection DSL, cable, satellite, etc. –VoIP is a collection of protocols Not a single protocol –Vendors Skype Vonage

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Terminal Emulation Allows access to other computers as if you were there University of Cambridge’s VNC –Free and totally cross-platform –Can run and control Windows from a Macintosh system

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Terminal Emulation Remote Desktop –Microsoft’s implementation –Free and built into system Remote Assistance –End user requests help –Helper can take control of desktop If permission granted

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Beyond A+ Online gaming –World of Warcraft (WOW) Chat –Internet Relay Chat (IRC)

© 2007 The McGraw-Hill Companies, Inc. All rights reserved Beyond A+ File sharing –Allows users to share files with other users Users can access any shared files (such as MP3s) on any computer anywhere on the Internet Napster and Kazaa are file sharing programs –Music industry trying to stop file sharing –BitTorrent protocol to counter music industry Also used for Linux distributions µTorrent is one program using BitTorrent protocol

© 2007 The McGraw-Hill Companies, Inc. All rights reserved