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The Internet. Chapter 22. Overview. In this chapter, you will learn to Explain how the Internet works Connect to the Internet Use Internet software tools. Internet. Historical/Conceptual. How the Internet Works. Internet Tiers. Tier 1 (main tier) Nine companies
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The Internet Chapter 22
Overview • In this chapter, you will learn to • Explain how the Internet works • Connect to the Internet • Use Internet software tools
Internet Historical/Conceptual How the Internet Works
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
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
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
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
Connection Concepts • 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
Essentials CompTIA A+Essentials Getting the Right Sound Card Connecting to the Internet
Ways of Connecting • Dial-up • Analog • ISDN • Dedicated • DSL • Cable • LAN • Wireless • Satellite
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 signalsinto analog signals
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 Modems
Baud Rate • 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
Communication Standards • 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
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 Flow Control (Handshaking) • 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
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
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 connectionand use the wizard
Dial-up Networking • Completing the setup of a dial-up Internet connection
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
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
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 feetfrom the closest main phoneservice switching center
Cable • 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
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
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
Windows XP Firewall • Built into Windows XP • Originally named Internet Connection Firewall (ICF) • Changed to Windows Firewall in SP2
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
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
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
E-mail • Two most popular e-mail programs • Microsoft Outlook Express • Mozilla Thunderbird • E-mail protocols • Post Office Protocol version 3 (POP3) • Used for receiving e-mail • Internet Message Access Protocol (IMAP) • Used for receiving mail, but with more features than POP3 • Simple Mail Transfer Protocol (SMTP) • Used for sending e-mail
E-mail • Configuring e-mail • Can use name or IP
Newsgroups • Use a newsreader program to access newsgroups • Outlook Express most common newsreader (free) • News servers run Network News Transfer Protocol (NNTP)
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: e-mail address
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
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
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 Terminal Emulation
Beyond A+ • Online gaming • World of Warcraft (WOW) • Chat • Internet Relay Chat (IRC)
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